Word & character counter
Count words, Unicode characters, lines, sentences and UTF-8 bytes.
Open tool2541.CN / Tools
All tools
Practical tools for everyday work. Convert, create, calculate, and keep things moving.
280 Results
Case converter
Convert letter case, title case, sentence case, camelCase or snake_case.
Open toolURL slug generator
Create a clean lowercase slug while preserving Unicode letters.
Open toolRemove duplicate lines
Remove duplicate lines and preserve the first occurrence.
Open toolSort lines
Sort text alphabetically, naturally, by length or numerically.
Open toolReverse text
Reverse text by grapheme, word or line.
Open toolFind & replace
Replace literal text without interpreting regular expressions.
Open toolClean whitespace
Trim lines, collapse repeated spaces, and remove empty lines.
Open toolJoin lines
Join multiple lines with a chosen separator.
Open toolSplit text
Split text using a literal separator into separate lines.
Open toolAdd line numbers
Add configurable line numbers to your text.
Open toolPrefix & suffix lines
Add a prefix and suffix to each input line.
Open toolWord frequency
Count words and rank them by frequency.
Open toolCompare text
Compare two documents line by line with an ordered edit summary.
Open toolExtract email addresses
Find and deduplicate common email address patterns in text.
Open toolExtract web URLs
Extract HTTP and HTTPS links from text.
Open toolHTML to plain text
Remove HTML tags and decode standard character references.
Open toolTruncate text
Shorten text by Unicode character count, optionally at a word boundary.
Open toolRepeat text
Repeat a phrase a controlled number of times.
Open toolWrap text
Wrap paragraphs at a chosen width without splitting words.
Open toolPad text lines
Pad lines to a fixed width using a chosen character.
Open toolPalindrome checker
Check whether letters and numbers read the same forwards and backwards.
Open toolAnagram checker
Compare the normalized letter counts of two phrases.
Open toolRemove line numbers
Remove leading numbered-list markers from copied text.
Open toolFilter text lines
Keep or remove lines containing a literal substring.
Open toolText to formatted list
Turn lines into a Markdown, HTML, JSON or SQL string list.
Open toolEnglish readability calculator
Estimate Flesch reading ease and grade level using a syllable heuristic.
Open toolJSON formatter & validator
Validate JSON and format or minify it with configurable indentation.
Open toolJSON to CSV
Convert an array of flat objects into a properly quoted CSV table.
Open toolCSV to JSON
Parse quoted CSV with embedded commas and line breaks into JSON.
Open toolCSV delimiter converter
Parse and rewrite CSV with a different separator.
Open toolCSV to Markdown table
Convert CSV rows into a Markdown table.
Open toolCSV column selector
Select named CSV columns and preserve their chosen order.
Open toolJSON path reader
Read a nested JSON value using dot notation and array indexes.
Open toolFlatten & unflatten JSON
Convert nested objects into dot-path keys, or restore them.
Open toolSort JSON keys
Recursively sort object keys while preserving array order.
Open toolJSON to TypeScript type
Infer a TypeScript type from a JSON sample.
Open toolQuery string ↔ JSON
Convert URL parameters and JSON objects, retaining repeated parameters.
Open toolBase64 encoder & decoder
Encode Unicode text to Base64 or decode valid UTF-8 Base64.
Open toolURL encoder & decoder
Encode or decode URL components using UTF-8 percent encoding.
Open toolHTML entity converter
Encode HTML-sensitive characters and decode named or numeric references.
Open toolUnicode escape converter
Convert text to Unicode escape sequences and back.
Open toolText ↔ binary / hex bytes
Encode text as UTF-8 bytes in binary, octal, decimal or hex.
Open toolCharacter code inspector
Inspect each character’s Unicode code point and UTF-8 bytes.
Open toolQuoted-printable converter
Encode or decode UTF-8 quoted-printable text used in email content.
Open toolJWT payload decoder
Read JWT headers and payloads without verifying their signature.
Open toolJSON string escape / unescape
Escape text as a JSON string or decode a quoted JSON string.
Open toolLine ending converter
Normalize text line endings to LF, CRLF or CR.
Open toolUnix permission calculator
Convert octal permissions to symbolic read/write/execute permissions.
Open toolInteger base converter
Convert signed integers between bases 2 through 36 without floating-point loss.
Open toolTwo’s complement converter
Convert signed integers to fixed-width binary and back.
Open toolIEEE 754 inspector
Inspect binary32 or binary64 floating-point representations.
Open toolReverse byte order
Reverse hexadecimal bytes, optionally within fixed-width groups.
Open toolBitwise calculator
Compute AND, OR, XOR, shifts and fixed-width NOT on integers.
Open toolURL inspector
Break a web URL into its protocol, host, path, query and fragment.
Open toolRelative URL resolver
Resolve relative paths against a base URL.
Open toolCampaign URL builder
Add UTM campaign parameters without losing existing query parameters.
Open toolInternational domain encoder
Convert a Unicode domain to its ASCII IDN form using the URL standard.
Open toolIPv4 number converter
Convert dotted IPv4 addresses to integers, binary and hexadecimal.
Open toolIPv4 subnet calculator
Calculate the network, mask, address range and conventional host range.
Open toolSEO meta tag generator
Generate escaped title, description, canonical and Open Graph metadata.
Open toolRobots.txt generator
Create a robots.txt file from allowed and disallowed path lists.
Open toolXML sitemap generator
Generate an XML sitemap from absolute HTTP or HTTPS URLs.
Open toolHTTP status reference
Look up common HTTP status codes and their meanings.
Open toolFile MIME type reference
Find common media types by file extension or type name.
Open toolRegular expression tester
Find JavaScript regular-expression matches with a bounded execution time.
Open toolCron next-run calculator
Preview the next UTC executions of a standard five-field cron expression.
Open toolScientific calculator
Evaluate arithmetic, powers, parentheses and common scientific functions.
Open toolPercentage calculator
Calculate a percentage of a number and the corresponding remainder.
Open toolPercentage change
Calculate absolute and percentage change between two values.
Open toolPart as percentage
Find what percentage one value represents of a total.
Open toolDiscount calculator
Find the sale price, savings and final price after tax.
Open toolTax / VAT calculator
Add tax to a net amount or extract tax from a gross amount.
Open toolTip & bill splitter
Calculate the tip and divide a bill equally.
Open toolUnit price comparison
Compare two packages using their price and quantity in the same unit.
Open toolCompound interest calculator
Project compound growth with optional end-of-month contributions.
Open toolFixed-rate loan calculator
Calculate a level monthly payment and total interest.
Open toolSimple interest calculator
Calculate interest without compounding.
Open toolAnnualized growth calculator
Calculate compound annual growth between positive start and end values.
Open toolReturn on cost calculator
Calculate profit and return relative to an initial cost.
Open toolInflation adjustment
Model future prices or purchasing power at an entered constant inflation rate.
Open toolBreak-even calculator
Find the unit sales needed to cover fixed costs.
Open toolMargin & markup calculator
Compare gross margin and markup from cost and sale price.
Open toolSalary ↔ hourly pay
Convert annual pay and hourly pay with your work schedule.
Open toolTrip fuel cost
Estimate fuel and cost from distance, consumption and unit price.
Open toolElectricity cost calculator
Estimate energy use and cost from appliance power and usage hours.
Open toolExact fraction calculator
Add, subtract, multiply or divide fractions with integer arithmetic.
Open toolDecimal to exact fraction
Turn a finite decimal string into a reduced exact fraction.
Open toolGCD & LCM calculator
Calculate the greatest common divisor and least common multiple of integers.
Open toolPrime number checker
Check whether an unsigned 64-bit integer is prime.
Open toolPrime factorization
Factor a positive integer up to one trillion.
Open toolPrime range generator
List prime numbers inside a bounded interval.
Open toolModular exponentiation
Compute a raised to b modulo m using exact integer arithmetic.
Open toolFactorial calculator
Calculate exact factorials with arbitrary-precision integers.
Open toolCombinations & permutations
Calculate n choose r and ordered selections without repetition.
Open toolFibonacci sequence
Generate the Fibonacci sequence starting with 0 and 1.
Open toolArithmetic sequence calculator
Calculate terms and the sum of an arithmetic sequence.
Open toolGeometric sequence calculator
Calculate terms and the sum of a geometric sequence.
Open toolDescriptive statistics
Calculate count, sum, mean, median, range and population/sample deviation.
Open toolWeighted average
Calculate an average with nonnegative weights.
Open toolPercentile calculator
Compute a percentile using linear interpolation between sorted observations.
Open toolZ-score calculator
Express a value as standard deviations from a mean.
Open toolLinear regression
Fit y = ax + b and calculate the Pearson correlation for paired data.
Open toolQuadratic equation solver
Solve ax² + bx + c = 0, including complex roots.
Open toolTwo-variable equation solver
Solve a two-equation linear system using determinants.
Open toolMatrix calculator
Add, subtract or multiply two numeric matrices.
Open toolMatrix transpose
Swap matrix rows and columns.
Open toolMatrix determinant
Calculate the determinant of a square matrix with pivoting.
Open toolMatrix inverse
Invert a nonsingular square matrix using Gauss–Jordan elimination.
Open toolPolynomial evaluator
Evaluate polynomial coefficients in descending order using Horner’s method.
Open toolNumber rounding
Round to decimal places or significant figures.
Open toolRatio simplifier
Reduce an integer ratio to its simplest form.
Open toolProportion calculator
Solve a : b = c : x for the missing fourth value.
Open toolRoman numeral converter
Convert canonical Roman numerals and integers from 1 through 3999.
Open toolCircle calculator
Calculate circle area and circumference from its radius.
Open toolTriangle from three sides
Calculate area, perimeter and angles from three valid side lengths.
Open toolRight triangle calculator
Find a hypotenuse or missing leg using the Pythagorean theorem.
Open toolRectangle calculator
Calculate rectangle area, perimeter, diagonal and aspect ratio.
Open toolSphere calculator
Calculate sphere volume and surface area from its radius.
Open toolCylinder calculator
Calculate cylinder volume, curved area and total surface area.
Open toolCone calculator
Calculate a right circular cone’s volume and surface area.
Open toolRectangular prism calculator
Calculate volume, surface area and diagonal of a rectangular prism.
Open toolDistance, midpoint & slope
Calculate the distance, midpoint and slope between two points.
Open toolScreen pixel density
Calculate pixels per inch from resolution and diagonal size.
Open toolAspect ratio & resize calculator
Preserve an aspect ratio when resizing to a new width.
Open toolLength converter
Convert length between clearly labeled units.
Open toolArea converter
Convert area between clearly labeled units.
Open toolVolume converter
Convert volume between clearly labeled units.
Open toolMass converter
Convert mass between clearly labeled units.
Open toolSpeed converter
Convert speed between clearly labeled units.
Open toolDuration converter
Convert duration between clearly labeled units.
Open toolEnergy converter
Convert energy between clearly labeled units.
Open toolPower converter
Convert power between clearly labeled units.
Open toolPressure converter
Convert pressure between clearly labeled units.
Open toolData size converter
Convert data size between clearly labeled units.
Open toolAngle converter
Convert angle between clearly labeled units.
Open toolFrequency converter
Convert frequency between clearly labeled units.
Open toolForce converter
Convert force between clearly labeled units.
Open toolTorque converter
Convert torque between clearly labeled units.
Open toolDensity converter
Convert density between clearly labeled units.
Open toolAcceleration converter
Convert acceleration between clearly labeled units.
Open toolData transfer rate converter
Convert data transfer rate between clearly labeled units.
Open toolTemperature converter
Convert Celsius, Fahrenheit and Kelvin with an absolute-zero check.
Open toolFuel economy converter
Convert liters per 100 km and US/imperial miles per gallon.
Open toolCSS px / rem / em converter
Convert CSS pixels and relative font units with an explicit base size.
Open toolCurrency converter with your rate
Convert amounts using an exchange rate you provide.
Open toolDownload time calculator
Estimate ideal transfer time from file size and network speed.
Open toolUnix timestamp converter
Convert Unix seconds or milliseconds and ISO 8601 instants.
Open toolDate difference calculator
Calculate the signed number of days between calendar dates.
Open toolAdd or subtract dates
Add calendar months and days, clamping month-end dates when needed.
Open toolBusiness day counter
Count weekdays between two dates, excluding an optional holiday list.
Open toolAge calculator
Calculate completed years, months and days between two dates.
Open toolLeap year checker
Check a Gregorian year and its February length.
Open toolISO week number
Find the ISO week-year, week number and weekday.
Open toolTime zone converter
Show the same instant in several IANA time zones.
Open toolMonthly calendar
Generate a Monday-first calendar for a Gregorian month.
Open toolAdd time durations
Add hours:minutes:seconds durations, including durations longer than a day.
Open toolTimecode ↔ frames
Convert non-drop-frame timecode and frame counts at integer frame rates.
Open toolLocalized date formatter
Format an ISO instant in a chosen locale and time zone.
Open toolRandom integer generator
Generate uniformly sampled integers within inclusive bounds.
Open toolRandom choice picker
Choose one or more entries from a list without replacement.
Open toolShuffle a list
Shuffle lines with the Fisher–Yates algorithm.
Open toolRandom team generator
Shuffle participants into balanced random teams.
Open toolDice roller
Roll configurable fair dice and calculate the total.
Open toolCoin flip
Flip a fair virtual coin and summarize heads and tails.
Open toolUUID v4 generator
Generate cryptographically random UUID version 4 identifiers.
Open toolRandom date generator
Pick calendar dates uniformly within an inclusive date range.
Open toolRandom string generator
Generate unbiased random strings from your chosen character set.
Open toolColor code converter
Convert HEX or RGB to RGB, HSL, HSV and CMYK coordinates.
Open toolHSL to HEX
Create RGB and HEX colors from hue, saturation and lightness.
Open toolColor contrast checker
Calculate contrast ratio and WCAG AA/AAA text thresholds.
Open toolColor harmony palette
Generate complementary, analogous, triadic or tetradic HSL palettes.
Open toolColor tints & shades
Blend a color with white and black to create tints and shades.
Open toolBlend two colors
Mix two opaque sRGB colors by a chosen percentage.
Open toolCSS gradient generator
Generate a two-color CSS linear or radial gradient.
Open toolCSS box shadow generator
Generate a configurable CSS box-shadow declaration.
Open toolInvert a color
Calculate the RGB complement of an opaque color.
Open toolFullwidth ↔ halfwidth text
Convert fullwidth ASCII forms and spaces to halfwidth, or the reverse.
Open toolChinese number words
Convert integers to standard or financial Chinese number words.
Open toolRMB uppercase amount
Convert a nonnegative amount with up to two decimal places to financial Chinese.
Open toolChinese punctuation converter
Convert common Chinese and ASCII punctuation marks.
Open toolChinese lunar date
Show a Gregorian date in the Chinese lunar calendar using browser calendar data.
Open toolUnicode normalization
Normalize Unicode text to NFC, NFD, NFKC or NFKD.
Open toolInteger to English words
Write signed integers up to 999 trillion in English words.
Open toolImage compressor
Reduce image dimensions and encode a smaller WebP or JPEG, with an exact before-and-after size comparison.
Open toolImage format converter
Convert browser-readable images to PNG, JPEG or WebP and choose a background for JPEG output.
Open toolImage resizer
Resize an image to a chosen width and height, optionally keeping its original proportions.
Open toolImage cropper
Crop a precise rectangle using pixel coordinates measured from the top-left corner.
Open toolRotate image
Rotate an image by any angle while retaining the complete picture on an expanded canvas.
Open toolFlip image
Mirror an image horizontally, vertically or across both axes.
Open toolGrayscale image
Turn an image into grayscale using weighted RGB luminance.
Open toolInvert image colors
Invert RGB colors while preserving the alpha channel.
Open toolSepia photo effect
Apply a warm sepia color transformation to a photo.
Open toolBlack and white threshold
Convert pixels to pure black or white at a selected luminance threshold.
Open toolBrightness and contrast
Adjust brightness and contrast with predictable RGB pixel operations.
Open toolImage saturation
Increase color intensity or blend an image toward grayscale.
Open toolBlur image
Apply a Gaussian-style canvas blur to soften an image.
Open toolSharpen image
Enhance edge contrast with a configurable sharpening convolution.
Open toolPixelate image
Create mosaic blocks by downsampling and enlarging with smoothing disabled.
Open toolAdd image border
Add an even colored border around all four edges without covering the original image.
Open toolRound image corners
Round image corners and retain a transparent background in the exported PNG.
Open toolCircular image crop
Make a centered circular avatar with transparent corners.
Open toolText watermark
Place a text watermark at the center or near a corner of your image.
Open toolLogo watermark
Overlay a local logo image with adjustable size and opacity.
Open toolImage contact sheet
Combine multiple images into a labeled grid with consistent thumbnail sizes.
Open toolSplit image into tiles
Cut an image into rows and columns and download each tile or one ZIP archive.
Open toolImage information
Inspect decoded dimensions, aspect ratio, file type and uncompressed RGBA memory size.
Open toolImage to data URL
Encode a local image as a complete Base64 data URL for inline use.
Open toolImage opacity
Reduce the opacity of an image while preserving existing transparency.
Open toolReplace image color
Replace pixels near a selected RGB color using a distance tolerance.
Open toolMake a color transparent
Remove pixels matching a background color, with an adjustable RGB tolerance.
Open toolTrim transparent margins
Find the nontransparent pixel bounds and remove empty margins automatically.
Open toolExtract image palette
Find common quantized colors from a sampled image and generate a downloadable palette.
Open toolDuotone image
Map image luminance between two chosen colors for a duotone effect.
Open toolExtract color channel
Visualize a red, green, blue or alpha channel as a grayscale image.
Open toolImage to ICO favicon
Create a Windows ICO favicon containing a PNG-encoded icon at your selected size.
Open toolSVG to PNG or WebP
Rasterize safe, self-contained SVG source at a chosen size.
Open toolMerge PDF files
Combine pages from multiple PDFs in the order the files are selected.
Open toolExtract PDF pages
Create one new PDF containing a selected list or range of pages.
Open toolSplit PDF into files
Split a PDF into individual pages or groups and download them in one ZIP.
Open toolReorder PDF pages
Build a PDF in an explicit page order, including reversed ranges or repeated pages.
Open toolRemove PDF pages
Delete selected pages and keep all remaining pages in their original order.
Open toolRotate PDF pages
Rotate selected PDF pages clockwise in quarter-turn steps.
Open toolPDF information
Inspect page count, dimensions, rotation and standard document metadata.
Open toolEdit PDF metadata
Replace a PDF title, author, subject and keywords with values you choose.
Open toolAdd PDF page numbers
Add simple page numbers to the top or bottom margin of a PDF.
Open toolWatermark PDF
Add an angled text watermark to each PDF page.
Open toolImages to PDF
Place local images on separate PDF pages, preserving their order and proportions.
Open toolPDF to images
Render selected PDF pages to PNG or JPEG images with a local PDF engine.
Open toolExtract PDF text
Extract an existing PDF text layer into a plain text file, page by page.
Open toolFlatten PDF form fields
Merge existing form field appearances into PDF page content.
Open toolRead PDF form fields
List AcroForm field names, field types and their current values as JSON.
Open toolOptimize PDF structure
Rewrite a PDF with object streams and report whether the resulting file is smaller.
Open toolCreate ZIP archive
Package local files into a standard ZIP archive with selectable compression.
Open toolExtract ZIP files
Extract individual files from a ZIP archive without uploading the archive.
Open toolInspect ZIP contents
Read archive entry names and declared compressed and expanded sizes.
Open toolGzip file compressor
Compress one local file using GZIP format.
Open toolGzip file decompressor
Decompress one local file using GZIP format.
Open toolZlib file compressor
Compress one local file using ZLIB format.
Open toolZlib file decompressor
Decompress one local file using ZLIB format.
Open toolRaw DEFLATE compressor
Compress one local file using raw DEFLATE format.
Open toolRaw DEFLATE decompressor
Decompress one local file using raw DEFLATE format.
Open toolFile to hexadecimal
Read file bytes as hexadecimal, with optional offset and ASCII columns.
Open toolHexadecimal to file
Turn pairs of hexadecimal digits into downloadable binary bytes.
Open toolFile to Base64
Encode arbitrary local file bytes as Base64 text.
Open toolBase64 to file
Decode Base64 text or a data URL into an exact binary file.
Open toolSplit binary file
Split a file into ordered binary chunks and package them in a ZIP archive.
Open toolJoin binary files
Concatenate selected file bytes in filename order or selection order.
Open toolText hash generator
Calculate SHA-256, SHA-384, SHA-512, SHA-1, MD5 or CRC32 over UTF-8 text.
Open toolFile checksum calculator
Calculate cryptographic hashes and CRC32 for a local file and compare a known checksum.
Open toolHMAC generator
Create a keyed HMAC over UTF-8 text using SHA-256, SHA-384 or SHA-512.
Open toolPBKDF2 key derivation
Derive a key from a password using PBKDF2-HMAC-SHA-256 with an explicit salt and iteration count.
Open toolEncrypt text with AES-GCM
Encrypt text with authenticated AES-256-GCM and a password-derived key.
Open toolDecrypt AES-GCM text
Authenticate and decrypt a text envelope created by the AES-GCM encryption tool.
Open toolEncrypt a file
Encrypt file content and its original filename in a password-protected AES-GCM envelope.
Open toolDecrypt a file
Restore file bytes from a password-protected 2541 AES-GCM envelope.
Open toolRSA key pair generator
Generate a fresh RSA public/private key pair and export standard PEM keys.
Open toolRSA-OAEP text encryption
Encrypt a short UTF-8 message with an RSA public key using OAEP and SHA-256.
Open toolRSA-OAEP text decryption
Decrypt a Base64 RSA-OAEP message with its PKCS#8 private key.
Open toolRSA-PSS message signing
Sign UTF-8 text with RSA-PSS, SHA-256 and a 32-byte salt.
Open toolVerify RSA-PSS signature
Verify that a message matches an RSA-PSS signature and public key.
Open toolQR code generator
Create a standards-based QR code for text or a URL, entirely in your browser.
Open toolWi-Fi QR code
Encode a Wi-Fi network name, security type and password in a scannable QR code.
Open toolContact QR code
Create a vCard QR code with a name, phone number, email and organization.
Open toolRead QR code from image
Decode the first readable QR symbol in an uploaded image without following its link.
Open toolBarcode generator
Generate CODE128, CODE39, EAN or UPC barcodes with a local encoder.
Open toolAudio to WAV
Decode a supported audio file and export its samples as 16-bit PCM WAV.
Open toolTrim audio
Extract a precise time range and save it as an uncompressed WAV file.
Open toolReverse audio
Reverse the samples in every audio channel to produce backward playback.
Open toolAdjust audio volume
Apply a volume change in decibels and report samples that would clip.
Open toolNormalize audio peak
Scale every channel together so the highest sample reaches a chosen peak level.
Open toolAudio fade in and out
Apply linear fade-in and fade-out envelopes to the ends of an audio file.
Open toolMono and stereo converter
Average channels into mono or duplicate mono samples into stereo.
Open toolAudio speed and pitch
Change playback speed by resampling; the pitch changes together with the speed.
Open toolJoin audio files
Join supported audio files in selection order and export one WAV file.
Open toolAudio information
Inspect decoded duration, channel count, sample rate and peak levels.
Open toolAudio waveform image
Render a waveform overview with min/max sample peaks and a time scale.
Open toolCapture video frame
Save a still PNG or WebP image from a chosen point in a local video.
Open toolVideo information
Inspect decoded video dimensions, duration, aspect ratio and file size.
Open toolImage text recognition (OCR)
Recognize printed English, Simplified Chinese, Traditional Chinese or Japanese text using local OCR models.
Open toolNo matching tools. Try a shorter keyword.