Data & computing
Generators and converters for identifiers, tokens, structured data and the test fixtures you need at 2am. 43 tools, including Barcode generator, CSV / JSON / YAML converter, Fake data generator and QR Code Generator. All free, with no account and nothing to install.
Barcode generatorGenerate an EAN, UPC, CODE128 or CODE39 barcode and download it as SVG or PNG.CSV / JSON / YAML converterConvert between CSV, TSV, JSON and YAML, and see the rows as a table.Fake data generatorGenerate mock people as JSON, NDJSON, CSV or SQL — columns and countries of your choosing.QR Code GeneratorCreate a QR code from any text or URL — free.ASCII Table ReferenceFull ASCII table (0-127) with a decimal / hex / octal / binary / character converter and a text-to-codes panel.Aspect ratio calculatorFind the aspect ratio of any width and height, like 16:9.Audio file size calculatorEstimate an uncompressed audio file's size from its length, sample rate and bit depth.Bandwidth CalculatorEstimate the internet speed your household needs.Binary to text converterDecode 8-bit binary back into readable text (spaces between bytes are optional).Bitrate CalculatorCompute the bitrate of a media file from its size and duration.Citation Generator (APA / MLA / Chicago)Generate a correctly formatted reference-list entry and in-text citation (or footnote) in APA 7, MLA 9 or Chicago 17 for websites, books, journal articles and newspapers, with one-click copy.Cron expression generatorBuild a cron schedule field by field — minute, hour, day of month, month, weekday — and see the expression and a plain-language description update live. One-click presets cover the common schedules, and the syntax (*, */5, 1-5, 1,15) is explained inline.Crop factor calculatorFind the equivalent full-frame focal length of a lens on a crop sensor.Data usage calculatorEstimate your monthly data usage from hours of activity per day.Depth of Field (DoF) CalculatorHyperfocal distance and the near/far sharp limits for a sensor, focal length, aperture and subject distance.Download time calculatorEstimate how long a download takes from the file size and your connection speed.Exposure Triangle CalculatorChange one of aperture, shutter or ISO and see how the other two compensate in stops to keep the exposure.Exposure value (EV) calculatorCompute the exposure value (EV) from aperture, shutter speed and ISO.Video frame count calculatorCompute how many frames a video contains from its duration and frame rate.Git command generatorA searchable, task-first Git cheat sheet: describe what you want to do — create a branch, undo the last commit, stash your work, squash, rebase, cherry-pick, force-push safely — and get the exact command with editable placeholders. Each is colour-coded by risk so you know which ones rewrite history or delete data.Golden Hour / Blue Hour CalculatorSunrise, sunset and the morning & evening golden and blue hours for any location and date.HTML CompressorMinify HTML by removing comments and collapsing whitespace to reduce page weight.Hyperfocal distance calculatorFind the hyperfocal distance for sharp landscape photos from focal length, aperture and circle of confusion.Is JavaScript enabled?A one-glance check of whether JavaScript is running in your browser — and a small demonstration of how sites detect it. If this page's live status shows enabled, JS is on; the classic trick is a <noscript> tag that only appears when it is off. It also reports whether cookies are enabled and if you are online.MAC Address GeneratorGenerate random MAC addresses with an optional vendor OUI prefix, unicast/multicast and UAA/LAA bits, in any format.Megapixel calculatorCompute the megapixels of an image from its width and height in pixels.Natural Language Unit ConverterType “5 miles in km” or “how many tablespoons in a cup” and get the answer — a deterministic parser, no AI, with the US and imperial gallon and pint kept apart.Online NotepadA clean, auto-saving notepad with word counts and .txt export — autosaved as you type, restored on your next visit.Paper Size Reference (A4, Letter, ISO 216)Every A, B, C and US paper size in mm, cm and inches, pixel dimensions at 72 to 600 dpi, a scale drawing against A4 and Letter, and the √2 rule explained.Photo File Size EstimatorEstimate the pixel dimensions and JPEG, RAW and TIFF file sizes from megapixels, aspect and bit depth.PPI calculatorCompute the pixel density (PPI) of a screen from its resolution and size.Print Cost CalculatorWork out the real cost per page and per job of printing — ink, paper, duplex and printer amortisation — and compare printing at home with a print shop.Print size calculatorFind the maximum print size of an image from its pixel dimensions and DPI.Query String BuilderBuild a URL query string from key/value rows with correct percent-encoding, array syntax options and a UTM preset — or parse an existing URL back into rows.Screen size calculatorCompute a screen's width and height in cm from its diagonal and aspect ratio.Storage Capacity CalculatorFind out how many files fit on a storage device.SVG OptimizerStrips editor metadata, empty groups, default attributes and excess decimals from an SVG, and reports the bytes saved. Parsed with DOMParser rather than regex, scripts and event handlers are always removed, and the preview renders in a sandboxed frame — a pasted SVG is executable XML.Text to binary converterConvert text to binary (8-bit) and decode binary back to text.Unix Permission Calculator (chmod)Convert between octal, symbolic and rwx Unix file permissions, with special bits and a chmod command.Upload Time CalculatorEstimate how long a file takes to upload at a given speed.Uptime / SLA calculatorTurn an uptime percentage into allowed downtime per year, month and day.Video file size calculatorEstimate a video's file size from its duration and bitrate.Web character encoding referenceEvery web form of é, à, €, the guillemets and the rest side by side: code point, HTML entity, numeric entity, UTF-8 bytes, percent-encoding for URLs and the JavaScript escape.