The whole toolbox at a glance — converters, calculators, colour checkers and generators that run entirely in your browser.
Length, weight, volume, area, speed, temperature, time and digital storage — exact factors, every unit at once, nothing uploaded.
Days between any two dates, add or subtract days, exact age in years-months-days, working days and days to your next birthday.
WCAG contrast ratio between any two colours with AA/AAA verdicts, the nearest accessible colour, and tints & shades palettes.
True random passwords from your browser’s cryptographic generator, with honest entropy maths — the password never touches our server.
Word counter, case converters (camelCase, snake_case, kebab…), URL & Base64 encoders and SHA-256 hashing — all offline, all instant.
BMI with WHO bands, your healthy weight range for height, BMR and daily calorie needs (Mifflin-St Jeor) plus body-fat and waist-to-height estimates.
Shrink a photo or screenshot right in your browser — resize, pick quality, compare before/after and download. Your file never uploads anywhere.
Look up any word’s meaning and translate it across dozens of human languages — plus ancient scripts and playful animal, alien and sound “languages”, with spoken pronunciation.
What is X% of Y, X is what percent of Y, percent change and add-or-subtract a percentage — with the arithmetic printed beside every answer.
Monthly loan payments, total interest, the effect of extra payments, and compound savings growth — the maths printed honestly, no quote requested.
Turn a link, text or Wi-Fi network into a QR code in your own browser, with error-correction controls and a print-ready PNG download.
Your public address, the ISP-level location databases infer from it, and every browser field a website can read — shown openly, nothing stored.
Epoch to date and back, with seconds/millisecond auto-detection, ISO 8601, your local zone and a live ticking clock.
Unbiased integers, d4–d100 dice and a raffle-style list picker — drawn from crypto.getRandomValues with rejection sampling, so nothing is favoured.
Merge, extract, delete, rotate and split PDF pages without uploading the file — the document is opened and re-saved by your own browser.
Format, minify and validate JSON with the exact line and column of a syntax error; large numbers and key order survive because it scans instead of re-parsing.
MD5, SHA-1, SHA-256, SHA-384 and SHA-512 of text or a whole file at once — verify a download against its published checksum privately.
UTF-8-correct Base64 both ways, URL-safe output, and a file turned into a data: URL — with the honest note that encoding is not encryption.
Compare up to eight cities hour by hour and find the call time that works for everyone — real IANA offsets and daylight saving, computed in the browser.
Random v4 and time-ordered v7 identifiers in bulk, plus a decoder that shows the version, variant and any embedded timestamp.
Any five-field cron schedule in plain English with its next ten runs, every field validated — including the day-of-month/day-of-week OR trap.
Test JavaScript regular expressions with live match highlighting, group inspection, and a common-pattern library (email, URL, IPv4, dates).
Paste CSV or TSV and see it as a formatted table instantly. Convert to JSON, copy or download — RFC 4180 compliant, all local.
Compare two blocks of text line-by-line or word-by-word: additions, deletions and unchanged parts highlighted instantly.
Break a URL into protocol, host, port, path, query parameters and fragment. Encode and decode components side-by-side.
Inspect any character: Unicode code point, HTML entity, UTF-8 bytes and UTF-16 unit count — a quick-reference for invisible bugs.
A live on-screen compass from your device’s magnetometer, plus the true-north bearing and great-circle distance to 46 world cities (a qibla pointer, the way home, the next town).
Convert between PNG, JPEG, WebP, BMP and ICO, and rasterise an SVG — resize, pick a quality, keep or replace transparency, download. The file never leaves your browser.
Put photos, scans or screenshots into one PDF — A4, US Letter or a page sized to each image — without uploading. JPEG and PNG files are embedded byte-for-byte, untouched.
Any whole number in base 2, 8, 10, 16 — or any base from 2 to 36 — computed exactly with BigInt, even numbers a desktop calculator overflows.
Text to UTF-8 bytes as 01101001 and back again, in binary, hex, octal or decimal — the honest way to see what a string really is.
Is it prime? A deterministic Miller–Rabin answer for numbers up to 2⁶³, plus the full prime factorisation when it is not.
Fractions that show their working: exact + − × ÷ with lowest terms by the Euclidean algorithm and the mixed-number form.
The full descriptive summary of any list of numbers — mean to quartiles — with the sample-vs-population choice made visible, not hidden.
Hourly to annual and back with your real schedule (hours per week, weeks per year), plus the 1.5× overtime figure — gross maths, no tax claims.
The restaurant napkin maths: tip, total and each person's share, with a round-up option so the payment is exact down to the coin.
Sale price from any percent off, a second coupon applied honestly on the remainder — and the equivalent single discount exposed.
A live seconds-accurate countdown to any date — exams, flights, launches, birthdays — that keeps counting up after it passes.
What you need on the final for the grade you want — or a straight "it is mathematically impossible" with the best achievable score.
Encode text so it survives an HTML parser and decode entity soup back, using the browser's own decoding table — nothing sent anywhere.
Read any JWT's header and claims with expiry dates made human — and an honest refusal to pretend an unsigned token is verified.
Numbers to Roman and back with the real canonical rules — the page tells you IIII is a clock, not a document.
Any number spelled out — including the cheque form banks actually ask for — exact up to 24 digits because it runs on integers, not floats.
A raw span of seconds read the way people say it — 2d 8h 16m 40s — and back, refusing to pretend a month has a fixed length.
Does this card/IBAN/ISBN/barcode pass its own check digit? The published algorithm, the working printed, and the honest limit: validity is not ownership.
The 500 g vs 1 kg decision settled by price per unit, with the percentage gap and what the other pack would cost at the winner’s rate.
The pump-and-odometer maths both traditions ask for — L/100 km and km/L and US MPG — plus what the trip actually cost.
The napkin maths of sleep: count back in 90-minute cycles from your alarm and see which bedtimes wake you mid-cycle-free.
Proper placeholder text — scrambled from the real De Finibus word bank, variable sentence lengths, no “asdfgh” filler.
Turn 1920×1080 into 16:9, check what a crop actually is, and resize to fit any box with the rounding error printed.
px to rem to pt with your real root font size, and an honest note about the one unit (em) that depends on context this page cannot see.
The true 2d6 curve computed as exact counts — 21 of 36 outcomes are 7 or better — with the full distribution as a table.
The two-minute question answered twice: theoretical minimum and the 85%-of-line-rate figure ISPs actually let you have.
Tukuk-OS