Tools

Small tools that do one thing. All of them run entirely in your browser — nothing is uploaded, there is no sign-up, and they keep working offline once the page has loaded.

Calculators

• Percentage calculator Work out a percentage of a number, what percent one number is of another, and percentage change.
• Loan and EMI calculator Monthly payment, total interest and total repaid for any loan amount, rate and term.
• BMI calculator Body mass index from height and weight, in metric or imperial, with what the number does and does not mean.
• Tip calculator Work out a tip and split the bill, with the per-person figure rounded sensibly.
• Age calculator Exact age in years, months and days from a date of birth, plus total days and the next birthday.
• Paint calculator How much paint a room needs, allowing for doors, windows and the number of coats.
• Compound interest calculator Growth of a lump sum plus regular contributions, with the interest shown separately.
• Calorie and BMR calculator Resting metabolic rate and daily calorie needs by activity level.
• Dog age calculator A dog's age in human years, using the research formula rather than multiplying by seven.
• Discount calculator Find the sale price and how much you save, including stacked discounts and tax.
• Days between dates Exact days, weeks, months and working days between two dates.
• Area and volume calculator Area, perimeter, volume and surface area for the common shapes and solids.
• Cat age calculator A cat's age in human years, using the veterinary life-stage mapping.
• Tile calculator How many tiles a floor or wall needs, including cuts and breakage.
• Concrete calculator Concrete volume for a slab, footing or post hole, in cubic metres and bags.
• Electricity cost calculator What an appliance costs to run, per hour, day, month and year.
• Water intake calculator How much water to drink a day, based on the actual reference intakes.
• Quadratic equation solver Solve ax² + bx + c = 0, including complex roots, with the working shown.
• Statistics calculator Mean, median, mode, standard deviation, quartiles and outliers from a list of numbers.
• Triangle solver Solve any triangle from three known values, with area, perimeter and all angles.
• Ohm's law calculator Voltage, current, resistance and power — give any two, get the other two.
• Molar mass calculator Molecular weight from a chemical formula, with the per-element breakdown.
• Flooring calculator How many packs of laminate, vinyl or engineered wood a room needs.
• Profit margin calculator Margin, markup and the price needed to hit a target margin.
• Running pace calculator Pace, time and distance — give any two and get the third, with split times.
• Prime number checker Test whether a number is prime, and get its factors if it is not.
• Permutations and combinations nPr, nCr, factorials, and whether order matters.
• Unit price comparator Compare packs of different sizes and prices to find which is genuinely cheaper.
• Wire gauge and voltage drop AWG to mm², current capacity and voltage drop over a run.
• Brick and block calculator How many bricks or blocks a wall needs, with mortar quantities.
• Inflation calculator What an amount is worth after years of inflation, in both directions.
• Fuel cost calculator Cost of a journey from distance, fuel economy and fuel price.
• TV size and viewing distance How far to sit from a television, or what size fits the distance you have.
• GCD and LCM calculator Greatest common divisor and least common multiple of any set of numbers.
• Speed, acceleration and momentum Velocity, acceleration, momentum, force and the equations of motion.
• Energy and power calculator Kinetic and potential energy, work, power, and what they cost in electricity.
• Pressure and density calculator Pressure from force and area, fluid pressure with depth, density and buoyancy.
• Dilution and concentration calculator C₁V₁ = C₂V₂, plus percentage, molarity and ppm conversions.
• Luggage and backpack weight Track pack weight against airline limits and the carry percentage of your body weight.
• Aspect ratio calculator Scale a width or height while keeping the ratio, and identify the ratio of any size.
• Roof pitch calculator Convert between roof pitch in degrees, ratio and percentage, and get rafter length.
• Pixel density (PPI) calculator Pixels per inch from resolution and screen size, with viewing distance guidance.
• Gear ratio and belt length Gear ratios, output speed and torque, and belt length between two pulleys.
• Aquarium volume and stocking Tank volume from its dimensions, with the real volume after substrate and displacement.
• Meeting cost calculator What a meeting costs in salary time, per hour and per year if it recurs.
• Wallpaper calculator How many rolls of wallpaper a room needs, allowing for pattern repeat.
• Shelf spacing and load calculator Even shelf spacing for a given height, and whether the span will sag.

Text tools

• Word and character counter Words, characters, sentences, paragraphs and reading time, counted as you type.
• Typing speed test Measure words per minute and accuracy on a one, two or five minute test.
• Remove duplicate lines Strip repeated lines from a list, keeping the first occurrence of each.
• Sort lines alphabetically Sort a list of lines A–Z, Z–A, by length, or numerically.
• JSON formatter and validator Pretty-print, minify and validate JSON, with the exact position of any error.
• Text compare Compare two blocks of text and see which lines were added, removed or changed.
• Regex tester Test a regular expression against sample text, with matches and capture groups shown.
• Case converter Convert text between upper, lower, title, sentence, camel, snake, kebab and other cases.
• Remove empty lines Delete blank lines from a block of text, optionally collapsing runs to one.
• Find and replace Replace every occurrence of a string in pasted text, with optional regex.
• Readability checker Flesch Reading Ease and grade level, with sentence length and passive voice flagged.
• Text cleaner Strip emojis, numbers, punctuation, extra spaces or line breaks from pasted text.
• XML, YAML, SQL and CSS formatter Pretty-print and minify XML, YAML, SQL, CSS and HTML.
• EXIF viewer and metadata remover See what metadata a photo carries, including GPS, and strip it out.
• Base64 encoder and decoder Encode text to Base64 or decode it back, entirely in your browser.
• URL encoder and decoder Percent-encode text for use in a URL, or decode it back.
• JWT decoder Decode a JSON Web Token to read its header, payload and expiry.
• Shuffle lines Randomly reorder a list of lines, using a proper unbiased shuffle.
• Reverse text Reverse text by character, by word, or reverse the order of lines.
• ROT13, Caesar and Morse Encode and decode ROT13, Caesar shifts, Morse code and Atbash.
• Markdown table generator Turn CSV or tab-separated data into a formatted Markdown table.
• Upside-down and mirror text Flip text upside down, mirror it, or convert it to other Unicode letterforms.
• Text splitter and list formatter Split into sentences or paragraphs, number lines, and convert between bullet styles.
• SVG optimiser and minifier Strip editor metadata, shorten numbers and minify an SVG.
• URL slug generator Turn a title into a clean, lowercase, hyphenated URL slug.
• Typographic scale and line height Build a modular type scale, and get sensible line height and measure.
• HTML escape and unescape Convert characters to HTML entities so markup displays as text, or convert back.
• Keyword density checker Count word and phrase frequency in text, with density as a percentage.

Generators

• Password generator Generate strong random passwords in your browser, with the entropy shown.
• Merge PDF files Combine several PDFs into one, in the order you choose.
• QR code generator Make a QR code for a link, text, WiFi network or contact details, and download it as SVG.
• Image resizer Resize an image to exact dimensions or a percentage, in your browser.
• Split and extract PDF pages Pull out a page range, split into single pages, or delete pages.
• Random number generator Random numbers in any range, plus dice, coin flips and a shuffled pick from a list.
• Random picker and team generator Pick a winner from a list, split into teams, or generate a random order.
• Image crop, rotate and flip Crop to an aspect ratio, rotate in 90° steps, or mirror an image.
• Lorem ipsum generator Generate placeholder text by paragraphs, sentences or words.
• Meta tag generator Generate title, description, canonical, Open Graph and Twitter Card tags.
• Printable graph paper Generate and print squared, dotted, isometric, hexagonal or lined paper.
• Dice roller Roll any dice notation — 2d6, 4d6 drop lowest, d20 with advantage.
• Pixelate or blur part of an image Cover faces, names or numbers by pixelating or blacking out a region.
• Rotate and reorder PDF pages Rotate individual pages or the whole document, and reorder pages.
• Hash generator SHA-1, SHA-256, SHA-384 and SHA-512 hashes of any text, computed in your browser.
• Make square and add padding Make an image square without cropping, add a border, or add a print safe margin.
• UUID generator Generate random version 4 UUIDs in your browser.
• robots.txt generator Build a robots.txt with crawler rules, AI bot access and a sitemap line.
• Schema markup generator Generate JSON-LD structured data for an organisation, article, FAQ, product or local business.
• Username and name generator Generate usernames, project names or pronounceable fake words.
• Decision maker Yes or no, or a weighted decision matrix scoring options against criteria.
• Add page numbers to a PDF Stamp page numbers onto an existing PDF, with position and start value.
• Printable ruler and scale check Print an accurate ruler in centimetres or inches, with a calibration check.

Colour

• Colour converter Convert a colour between HEX, RGB, HSL and CMYK, with a contrast check against black and white.
• Random colour and palette generator Generate random colours or a harmonious palette, with contrast checked.
• Colour shades and gradient generator Build a tint and shade scale from one colour, or a gradient between two.
• Extract colours from an image Pull the dominant colours out of an image as a palette.

Time

• Reaction time test Measure visual reaction time over five attempts, with the median reported.
• Time zone converter and meeting planner Convert a time between zones and find the overlap for a meeting.
• Stopwatch and countdown timer A stopwatch with laps and a countdown timer, running in your browser tab.
• Click speed test Clicks per second over a timed burst of 1, 5, 10 or 60 seconds.
• Countdown to a date Days, hours and minutes until any date, with the working days counted separately.
• Leap year and week number Whether a year is a leap year, the ISO week number, and the day of the week for any date.
• Metronome and tone generator A metronome with tap tempo, and a tone generator for any frequency.
• Reply delay timer Work out when to send a reply if you are matching the delay you were given.

Converters

• Image format converter and compressor Convert between JPEG, PNG and WebP, and compress with a quality slider.
• Number base converter Convert between binary, octal, decimal, hexadecimal and any base from 2 to 36.
• Unix timestamp converter Convert between Unix timestamps and human dates, in seconds or milliseconds.
• SVG to PNG converter Rasterise an SVG at any size, with transparency preserved.
• Cron expression parser Explain a cron expression in plain English and show the next run times.
• Mouse sensitivity and FOV converter Convert sensitivity between games so your aim carries across, and convert field of view.
• CSV to JSON converter Convert CSV to a JSON array of objects, or JSON back to CSV.
• Screen resolution and display info Your screen resolution, viewport size, pixel ratio, colour depth and refresh rate.