maratoolConverter tools
Transform between data formats, encodings, and units — all running locally in your browser.
Most used in Converter
Convert CSV to JSON
Convert CSV to JSON or JSON to CSV instantly. Auto-detects delimiters — supports comma, semicolon, and tab.
Convert JSON to Markdown Table
Paste a JSON array and instantly get a formatted Markdown table. Perfect for READMEs and documentation.
Convert HTML to Markdown
Paste HTML and get clean Markdown instantly. Handles headings, lists, links, images, tables, and code blocks.
Convert Markdown to HTML Online
Bidirectional Markdown ↔ HTML converter. Paste content and get instant output — headings, lists, links, code blocks, and more.
Base64 Encode / Decode
Encode text to Base64 or decode Base64 back to text. Also supports image to Base64.
Text to Binary
Convert text to binary, hex, and decimal representations instantly.
Convert MNG to APNG Online
Convert MNG (Multiple-image Network Graphics) to APNG in your browser. Preserves frames and timing — no upload, no watermark.
YAML to JSON Converter
Convert YAML to JSON or JSON to YAML instantly in your browser. No upload, no sign-up.
XML to JSON Converter
Convert XML to JSON instantly in your browser. Handles attributes, nested elements, and repeated tags.
Document Converter — DOCX to HTML, EPUB to Markdown & More
Convert DOCX, EPUB, ODT, HTML, Markdown, RTF, CSV, and JSON with Pandoc WASM in your browser. Upload, pick a format, preview, and download.
File Converter — Images, Audio, Video & Documents
Convert 180+ image formats, audio, video, and documents in your browser. ImageMagick, FFmpeg, and Pandoc WASM — all processing runs locally.
Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and vice versa, with timezone support.
PX to REM Converter
Convert pixels to rem and rem to pixels instantly. Configurable base font size with a common conversions reference table.
Unit Converter — Length, Weight, Temperature & More
Convert between units of length, weight, temperature, data, speed, and more. Free, instant, no sign-up.
Line Height Calculator
Calculate the optimal CSS line-height for any font size. Live preview and copy-ready CSS values.
Typography Size Converter — PX, PT, EM, %
Convert between px, pt, em, rem, and percent for CSS typography. Enter any value and see all units instantly.
Shoe Size Converter
Convert shoe, sneaker, and tennis shoe sizes between US, UK, EU, Brazil, Japan, Mexico, Australia, and cm. Men, women, and kids — instant and free.
FPS Converter — Change Video Frame Rate
Change video frame rate (FPS) online — convert between 24, 30, 60 fps and more. Runs entirely in your browser.
Video to GIF Converter — MP4 to GIF Online
Convert MP4, WebM, and MOV videos to animated GIFs in your browser. Trim start/end, set FPS, adjust size — no upload to servers.
Convert Animated WebP to MP4
Convert animated WebP images to MP4 video in your browser. Adjust quality and resolution, batch convert, then download.
Trim Video Online — Cut MP4, WebM, MOV
Trim and cut MP4, WebM, MOV videos online for free. Set start and end times, lossless — runs in your browser, no upload, no watermark.
Convert MP4 to MP3 — Extract Audio from Video
Extract audio from MP4, WebM, or MOV videos and download as MP3. Runs in your browser — no upload, no signup, no watermark.
Video to Text
Convert video to text online for free. Transcribe MP4, WebM, MOV, and audio to text, SRT, or VTT in your browser — no upload, no signup.
Convert MOV to MP4 — Free QuickTime Converter
Convert MOV (QuickTime) files to MP4 directly in your browser. Lossless when possible — no upload, no watermark, no signup.
Convert MP4 to WebM — Online Video Converter
Convert MP4 video files to WebM in your browser. No upload, no watermark, no signup — runs entirely on your device.
Compress Video Online — Reduce MP4 Size
Compress MP4, WebM, and MOV videos to a smaller file size. Choose a quality preset, runs entirely in your browser.
Rotate Video Online — Free Video Rotator
Rotate MP4, WebM, and MOV videos by 90, 180, or 270 degrees. Lossless — runs in your browser, no upload.
Mute Video Online — Remove Sound from Video
Remove audio from MP4, WebM, and MOV videos. Lossless — keeps video quality intact, runs in your browser.
Resize Video Online — Change Video Resolution
Resize videos to 1080p, 720p, 480p, or custom dimensions. Aspect-ratio lock available. Runs in your browser.
Crop Video Online — Free Video Cropper
Crop MP4, WebM, and MOV videos in your browser. Drag a crop box, pick an aspect ratio — no upload, no watermark, no signup.
Online Video Editor — Free Browser Video Tools
Free online video editor — trim, compress, convert, rotate, mute, crop, and resize videos in your browser. No upload, no signup, no watermark.
Instagram Video Downloader — Save Reels & Videos
Download Instagram Reels and videos in MP4 format. Paste the link, click download — free, no login, no watermark.
Paper Sizes Reference
Complete reference for paper sizes — A series, US Letter, Legal, Tabloid, and more. Search and filter by name or dimensions.
Time Zone Converter
Convert date and time between time zones instantly. Compare multiple zones side by side.
CSV Cleaner — Trim & Fix CSV Files
Clean CSV files online. Trim whitespace, remove empty rows, and fix line endings. Runs in your browser.
Remove Duplicate Rows from CSV
Remove duplicate rows from CSV files. Dedupe by entire row or a specific column. Instant, browser-based.
Split CSV File Online
Split a CSV file into multiple files by row count. Download-ready chunks for large datasets.
Merge CSV Files Online
Merge multiple CSV files into one. Combines headers automatically. Paste or type CSV content.
Age Calculator — Exact Age from Birth Date
Calculate exact age in years, months, and days from a birth date. Updates to today or any target date.
ISO 8601 Date Formatter
Parse and format ISO 8601 dates. Convert between ISO strings, local datetime, and Unix timestamps.
ISO Week Number Calculator
Find the ISO week number for any date. See week start, week end, and year-week label.
Convert EPUB to PDF Online
Convert EPUB e-books to PDF, HTML, or plain text. Preview chapters and download — runs in your browser, no upload.
Business Days Calculator
Count the working days between two dates, skipping weekends, so a five day SLA or a 30 day payment term lands on the right calendar day.
Working Hours Calculator
Add up hours worked from start and end times across a week, subtracting breaks, so a timesheet total is arithmetic rather than guesswork.
Countdown to Date Calculator
Pick a target date and see exactly how many days, hours and minutes are left, useful for a launch, a deadline or a contract renewal.
Excel to CSV Converter Online
Upload an .xlsx file or paste a table copied out of a sheet and get plain CSV rows back, with the formatting and formulas left behind.
CSV to Excel Converter Online
Turn CSV rows into a file Excel opens with the columns already split, avoiding the import wizard and the mangled dates it usually produces.
CSV Delimiter Converter
Switch a file between commas, semicolons, tabs and pipes, for when Excel in a European locale refuses to open a comma separated file correctly.
CSV Column Mapper & Renamer
Rename and reorder CSV headers to match the columns an importer expects, so a spreadsheet from one system loads into another without hand editing.
Transpose CSV Online
Flip rows into columns and columns into rows, for when data arrives the wrong way round for the chart or the import you need it for.
Convert GIF to MP4 Online
Turn an animated GIF into an MP4 a fraction of the size, which is the format Twitter, Discord, and most CMS uploads actually prefer.
Video to APNG Converter Online
Pick a clip range, frame rate, and width, then export it as an animated PNG with lossless color and real alpha instead of GIF dithering.
Video to WebP Converter Online
Trim a clip range, set frame rate and output width, and export animated WebP. Sharper than a GIF at a fraction of the bytes for web embeds.
Video to AVIF Converter Online
Export a clip as animated AVIF, the smallest of the modern animation formats. Start, end, frame rate, and width are all set before encoding.
Merge Videos Online — Join Video Clips
Queue MP4, WebM, or MOV clips, arrange the order, and join them end to end into one continuous file you can download in a single click.
Reverse Video Online
Play an MP4, WebM, or MOV clip backwards and export it. Both picture and audio are reversed, so the soundtrack runs with the footage.
Change Video Speed Online
Retime a clip anywhere from 0.25x to 4x and export the result, whether you want a timelapse or slow motion out of a phone recording.
Add Freeze Frame to Video Online
Hold one frame in the middle of a clip. Pick the timestamp and how many seconds it pauses, then export the video with the freeze baked in.
Video Screenshot — Extract Frame as Image
Scrub to a timestamp and save that exact frame as a PNG or JPG, which beats screenshotting the player and cropping the browser chrome off.
Images to Video — Slideshow MP4 Maker
Order a stack of photos, set the frame rate, and render them into an MP4 slideshow you can post anywhere a video file is accepted.
Convert OGG to MP3 — Free Online Converter
Convert OGG (Vorbis or Opus) files to MP3 in your browser. No upload, no signup — files never leave your device.
Convert Opus to MP3 — Free Online Converter
Convert Opus files to MP3 in your browser — including WhatsApp voice messages. No upload, no signup, files never leave your device.
Audio to Text
Convert audio to text online for free. Transcribe MP3, WAV, M4A, and more to text, SRT, or VTT in your browser — no upload, no signup.
Cut Audio Online — Trim MP3 WAV FLAC
Give a start and end time to keep one section of an MP3, WAV, or FLAC file, then download just that piece as a new track.
Compress Audio Online — Reduce MP3 Size
Pick a target bitrate and re-encode down to it. Taking a spoken-word track from 320 to 96 kbps cuts the file by roughly two thirds.
Merge Audio Files Online
Line up MP3, WAV, or OGG tracks in whatever order you want and stitch them into a single file with no silence dropped in between.
Audio Fade In Out Online
Set fade in and fade out lengths in seconds so a track eases in and ends without a hard cut. Total duration tells it where the tail sits.
Change Audio Speed Online
Speed a track up or slow it down, then download the retimed file. Built for lecture recordings, practice loops, and audiobook pacing.
Boost Audio Volume Online
Amplify a quiet recording by a set number of decibels and download the louder file, so an interview taken at arms length becomes audible.
GIF Frame Interpolation — Smooth Motion
Lift choppy footage to 30, 48, or 60 fps by generating the missing in-between frames with motion interpolation. Takes MP4, WebM, and MOV.
Video to JXL Converter Online
Encode video frames as JPEG XL instead of PNG or JPG, for photo quality stills at a fraction of the file size. Accepts MP4, WebM, and MOV.
Apply Video Filters Online
Push a clip through one of three looks: vivid color, flat grayscale, or full negative. The graded video is re-encoded to MP4 on your own machine.
Video Stabilizer Online
Take the jitter out of handheld footage. Motion is tracked across frames and the clip is re-rendered along a steadier path, no tripod required.
Add Subtitles to Video Online
Burn an SRT or VTT file permanently into the picture so the captions survive re-uploads to platforms that quietly strip subtitle tracks.
Audio Waveform Image Generator
Render any audio track as a 1200 by 200 pixel waveform PNG, the kind of image podcast pages, audiograms, and release posts run above the player.
Remove Audio Noise Online
Strip constant hiss, mains hum, and air conditioner rumble out of a recording, then download the cleaned voice track as an MP3.
Bulk WebP to PNG Converter
Turn a stack of WebP files into PNGs with transparency intact, for the apps and CMSes that still refuse to read WebP.
Bulk AVIF to PNG Converter
AVIF keeps files small but half the editors out there cannot open one. Convert a batch to PNG and get images that paste anywhere.
Bulk AVIF to JPG Converter
Convert a folder of AVIF photos to JPG at the quality you choose, for uploaders and marketplaces that reject the newer format.
Bulk PNG to JPG Converter
Flatten a batch of PNGs to JPG and set the compression level, for when screenshots and exports keep hitting an upload limit.
Bulk JPG to PNG Converter
Convert JPG photos to PNG in one pass, so every later edit and re-save avoids stacking another round of lossy compression.
Add Audio to Video Online
Drop in a silent clip and an audio track, set the volume, trim where the sound starts, and export an MP4 that plays with music.
Video to PNG — Extract Frames
Pull frames out of a video as lossless PNGs. Grab one exact moment, or export a whole sequence at the interval you set.
Video to JPG — Extract Frame
Take a still from a video without screen recording it. Export a single JPG or every frame at a fixed interval.
Area Converter — Square Feet, Square Meters, Acres & Hectares
Convert square feet to square meters, acres to hectares, and every common area unit instantly. Free area converter that runs in your browser.
Volume Converter — Liters, Gallons, Cups & More
Convert liters to gallons, cups to milliliters, and every common volume unit instantly. Free volume converter that runs entirely in your browser.
Pressure Converter — PSI, Bar, kPa & Atm
Convert psi to bar, kPa to psi, atmospheres, torr, and mmHg instantly with NIST conversion factors. Free pressure converter, runs in your browser.
Energy Converter — Joules, Calories, kWh & BTU
Convert joules to calories, kWh to BTU, electronvolts, and foot-pounds instantly with NIST factors. Free energy converter, runs in your browser.
Power Converter — HP to kW, Watts & BTU/h
Convert horsepower to kilowatts, watts to BTU/h, and tons of refrigeration instantly with NIST factors. Free power converter in your browser.
Force Converter — Newtons, Kilograms-Force & Pounds-Force
Convert newtons to pounds-force, kilograms-force, dynes, and poundals instantly with exact NIST factors. Free force converter in your browser.
Torque Converter — Nm to Ft-Lb
Convert newton-meters to foot-pounds, inch-pounds, and kgf·m instantly with exact NIST factors. Free torque unit converter in your browser.
Acceleration Converter — m/s², G-Force & More
Convert m/s² to g-force, ft/s², Gal, and km/h per second instantly with exact NIST factors. Free acceleration unit converter in your browser.
Density Converter — kg/m³, g/cm³ & lb/ft³
Convert kg/m³ to g/cm³, lb/ft³, lb/in³, and kg/L instantly with exact NIST-derived factors. Free density unit converter in your browser.
Angle Converter — Degrees, Radians & Gradians
Convert degrees to radians, gradians, arcminutes, arcseconds, and turns instantly. Free angle unit converter that runs entirely in your browser.
Frequency Converter — Hz, kHz, MHz & RPM
Convert hertz to kilohertz, megahertz, RPM, and radians per second instantly. Free frequency unit converter that runs entirely in your browser.
Bandwidth Converter — Mbps, MB/s & Gbps
Convert Mbps to MB/s, Gbps to Mbps, and MiB/s instantly — decimal and binary prefixes handled correctly. Free bandwidth converter in your browser.
Amount of Substance Converter — Moles & Millimoles
Convert moles to millimoles, micromoles, kilomoles, and pound-moles instantly. Free amount-of-substance converter that runs in your browser.
Molar Mass Converter — g/mol & kg/mol
Convert molar mass between g/mol, kg/mol, kg/kmol, daltons, and lb/lb-mol instantly. Free molar mass unit converter that runs in your browser.
Dynamic Viscosity Converter — Pa·s, Poise & Centipoise
Convert dynamic viscosity between Pa·s, poise, centipoise, and lbf·s/ft² instantly with NIST factors. Free viscosity converter in your browser.
Kinematic Viscosity Converter — m²/s, Stokes & Centistokes
Convert kinematic viscosity between m²/s, stokes, centistokes, and ft²/s instantly with exact NIST factors. Free viscosity converter in your browser.
Mass Flow Rate Converter — kg/s, kg/h & lb/h
Convert mass flow between kg/s, kg/h, tonnes per hour, lb/s, and lb/h instantly with exact NIST factors. Free flow rate converter in your browser.
Flow Rate Converter — L/min, GPM & CFM
Convert volumetric flow between L/min, GPM, CFM, m³/h, and L/s instantly with exact NIST factors. Free flow rate converter in your browser.
Capacitance Converter — Farads, µF, nF & pF
Convert capacitance between farads, microfarads, nanofarads, and picofarads instantly. Free capacitance unit converter that runs in your browser.
Electric Charge Converter — Coulombs, Ah & mAh
Convert electric charge between coulombs, ampere-hours, and milliamp-hours instantly. Free charge unit converter for battery and electronics work.
Electric Current Converter — Amps, Milliamps & Kiloamps
Convert electric current between amps, milliamps, microamps, and kiloamps instantly. Free current unit converter that runs in your browser.
Electric Potential Converter — Volts, Millivolts & Kilovolts
Convert electric potential between volts, millivolts, microvolts, kilovolts, and megavolts instantly. Free voltage unit converter in your browser.
Electrical Conductance Converter — Siemens & Mho
Convert electrical conductance between siemens, millisiemens, microsiemens, and mho instantly. Free conductance unit converter in your browser.
Electrical Resistance Converter — Ohms, kΩ & MΩ
Convert electrical resistance between ohms, kiloohms, megaohms, and gigaohms instantly. Free resistance unit converter that runs in your browser.
Inductance Converter — Henry, mH & µH
Convert inductance between henries, millihenries, microhenries, and nanohenries instantly. Free inductance unit converter that runs in your browser.
Tesla to Gauss Converter — Magnetic Field
Convert magnetic flux density between tesla, gauss, millitesla, and gamma instantly — 1 T = 10,000 G exactly. Free converter in your browser.
Magnetic Field Strength Converter — A/m & Oersted
Convert magnetic field strength H between amperes per meter and oersteds instantly — 1 Oe = 1000/4π A/m. Free converter in your browser.
Magnetic Flux Converter — Weber & Maxwell
Convert magnetic flux between webers, milliwebers, and maxwells instantly — 1 Wb = 10⁸ Mx exactly. Free flux unit converter in your browser.
Magnetomotive Force Converter — Ampere-Turns & Gilberts
Convert magnetomotive force between ampere-turns and gilberts instantly — 1 Gb = 10/4π At exactly. Free MMF unit converter in your browser.
Lux to Foot-Candles Converter — Illuminance
Convert illuminance between lux, foot-candles, and phots instantly — 1 fc = 10.764 lx exactly. Free lighting unit converter in your browser.
Luminance Converter — cd/m² (Nits) & Foot-Lamberts
Convert luminance between cd/m² (nits), foot-lamberts, stilbs, and lamberts instantly with exact NIST factors. Free converter in your browser.
Luminous Energy Converter — Lumen-Seconds & Talbots
Convert luminous energy between lumen-seconds, talbots, lumen-minutes, and lumen-hours instantly. Free photometry unit converter in your browser.
Luminous Flux Converter — Lumens
Convert luminous flux between lumens, kilolumens, millilumens, and candela-steradians instantly. Free photometry unit converter in your browser.
Luminous Intensity Converter — Candela & Candlepower
Convert luminous intensity between candela, millicandela, and candlepower instantly — LED mcd ratings included. Free converter in your browser.
Gray to Rad Converter — Absorbed Radiation Dose
Convert absorbed radiation dose between grays, milligrays, and rads instantly — 1 Gy = 100 rad exactly. Free dose unit converter in your browser.
Sievert to Rem Converter — Equivalent Radiation Dose
Convert equivalent radiation dose between sieverts, millisieverts, and rems instantly — 1 Sv = 100 rem exactly. Free converter in your browser.
Becquerel to Curie Converter — Radioactivity
Convert radioactivity between becquerels, megabecquerels, curies, and millicuries instantly — 1 Ci = 3.7×10¹⁰ Bq. Free converter in your browser.
MPG to L/100km Converter — Fuel Economy
Convert fuel economy between US MPG, UK MPG, L/100km, and km/L instantly. Free fuel consumption converter that runs entirely in your browser.
Wind Speed Converter — Knots, MPH, km/h & Beaufort Scale
Convert wind speed between knots, mph, km/h, and m/s and read the Beaufort scale force with description. Free wind converter in your browser.
Tire Size Calculator — Compare Tire Dimensions
Enter a tire size like 205/55R16 to get diameter, sidewall, and circumference — and compare two sizes with speedometer error. Free, in-browser.
Screen Size Calculator — TV & Monitor Dimensions
Turn a diagonal size and aspect ratio into real width, height, area, and PPI for TVs and monitors — inches and centimeters. Free, in-browser.
Clothing Size Converter — US, EU & UK Dress and Suit Sizes
Convert clothing sizes between US, UK, EU, Italian, and Japanese charts for women’s dresses, men’s suits, and shirts. Free, in your browser.
Hat Size Converter — US, UK & CM
Convert hat sizes between head circumference in cm or inches, US and UK numeric sizes, and S/M/L letters. Free hat size converter in your browser.
Describe Video with AI
Get a text description of every second of your video — an AI model describes each frame locally in your browser. No upload, no signup.
Days Between Dates
Count the days between two dates, with a years-months-days breakdown, weeks, hours, and business days that skip weekends.
About these converter tools
This page collects the conversions that come up over and over when moving data between systems — spreadsheets to APIs, configuration formats to each other, encoded blobs back to text, and timestamps between formats a human can read and ones a database expects. They are the kind of tasks where a fast browser tool beats writing a one-off script.
What is on this page
The tools group around three jobs. Data format converters translate structured data between representations — the CSV to JSON converter reads a spreadsheet export and produces a JSON array suitable for an API or a fixture file, and the YAML to JSON converter moves between the formats most configuration systems alternate between (Kubernetes, GitHub Actions, OpenAPI). Markup converters move between document formats — the HTML to Markdown converter cleans up a copy from a web page or rich text editor and produces Markdown you can paste into a README, a blog post, or a documentation site. Encoding and time converters handle the lower-level transforms — Base64 encoding, URL encoding, and the Unix timestamp converter, which translates between epoch seconds and human-readable dates in your local timezone or UTC.
Which to use when
Use the CSV to JSON converter when migrating data into an application that does not accept spreadsheets directly, or when seeding test fixtures from a finance or marketing export. Use the YAML to JSON converter when debugging a tool that requires one format but you authored configuration in the other — it is also useful for validating that your YAML actually parses. Use the HTML to Markdown converter when capturing content from the web into a writing workflow that uses Markdown. Use the unit converter for the cross-cutting cases — length, weight, temperature, data size — where a quick answer beats opening a calculator.
Privacy
Every converter on this page runs in your browser. Inputs are parsed, transformed, and rendered on your device — they are never uploaded to a server, logged, or stored remotely. That makes the tools safe for proprietary data exports, internal configs, and anything else you would not paste into a third-party service.