79 free tools · no sign-up
Quick answers, with the working shown.
Calculators and file tools that run entirely in your browser. What you type, and the files you open, never leave your device.
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Money
VAT, margins, discounts and pricing
- VAT CalculatorAdd VAT to a price, or take it out of a price that already includes it.
- Profit Margin CalculatorWork out margin from cost and price, or the price for the margin you want.
- Markup CalculatorFind the selling price from your cost and markup, or the markup from two prices.
- Discount CalculatorPrice after a percentage off, the discount from two prices, or the original price.
- Compound Interest CalculatorSee how savings grow with compound interest and regular payments.
Everyday calculations
Percentages, dates and hours
- Percentage CalculatorA percentage of a number, one number as a percentage of another, and more.
- Percentage Change CalculatorThe percentage increase or decrease between two numbers.
- Hours CalculatorHours worked between two times with breaks, or add up lengths of time.
- Date CalculatorDays, weeks and working days between two dates, or add days to a date.
- Electricity Cost CalculatorWhat an appliance costs to run per day, month and year.
Business
Break-even, ROI, subscriptions and growth
- Break-Even CalculatorHow many units you must sell to cover your costs or hit a profit target.
- ROI CalculatorReturn on investment as a percentage, with profit and average yearly return.
- Commission CalculatorSales commission at a flat rate or in tiers, or the sales needed for a target.
- Product Pricing CalculatorThe price to charge so fees and VAT still leave the margin you want.
- MRR & ARR CalculatorMonthly and annual recurring revenue from customers and average price.
- Subscription Revenue CalculatorForecast subscription revenue month by month, with sign-ups and churn.
- CAC Payback CalculatorHow many months a customer takes to pay back what it cost to win them.
- Price Increase Break-Even CalculatorHow many sales you can lose after a price rise before you earn less.
Freelance
Day rates, hourly rates and utilisation
- Freelance Day Rate CalculatorThe day and hourly rate a freelancer needs to hit an income target.
- Hourly Rate CalculatorThe hourly rate needed for an income target, or a salary as an hourly rate.
- Annual Income CalculatorTurn hourly, daily, weekly or monthly pay into a yearly income.
- Utilisation Rate CalculatorYour utilisation rate from billable and available hours, and what unbilled time costs.
- Project Profitability CalculatorWhat a project really paid per hour after expenses, against your target.
Maths
Fractions, quadratics and number theory
- Quadratic Equation SolverSolve ax² + bx + c = 0 with every step, including complex answers.
- Mean, Median & Mode CalculatorMean, median, mode, range and standard deviation for a list of numbers.
- Fraction CalculatorAdd, subtract, multiply or divide fractions and mixed numbers, step by step.
- Pythagorean Theorem CalculatorFind a missing side of a right-angled triangle, plus area and angles.
- GCF & LCM CalculatorGreatest common factor and least common multiple, with prime factors.
- Binary, Decimal and Hex ConverterBinary, octal, decimal and hexadecimal, with the working.
- Roman Numeral ConverterNumbers to Roman numerals and back, from 1 to 3,999.
- Circle CalculatorRadius, diameter, circumference and area from any one of them.
- Area CalculatorArea of rectangles, triangles, trapeziums, ellipses and polygons.
- Volume CalculatorVolume and surface area of boxes, cylinders, cones, spheres and pyramids.
- Sin Cos Tan CalculatorSin, cos and tan of any angle, with exact values.
- Prime Factorisation CalculatorPrime factors, divisors and whether a number is prime.
- Permutations and Combinations CalculatornPr, nCr and factorials, exact even for big numbers.
- Sequence Calculatornth term and sum of arithmetic and geometric sequences.
- Scientific Notation ConverterStandard form, E notation, engineering notation and significant figures.
- Logarithm CalculatorLogarithms to any base, natural logs and antilogs.
- Simultaneous Equations SolverSolve two linear equations in x and y, with the working.
- Ratio CalculatorSimplify a ratio, solve a proportion, or share an amount.
- Slope, Distance and Midpoint CalculatorDistance, midpoint, slope and line equation from two points.
Science
Density, Ohm's law, speed and temperature
- Ohm's Law CalculatorEnter any two of voltage, current, resistance and power to find the rest.
- Speed, Distance & Time CalculatorEnter any two of speed, distance and time to find the third.
- Density CalculatorEnter any two of mass, volume and density to find the third.
- Temperature ConverterConvert between Celsius, Fahrenheit and Kelvin, with the formula shown.
- Kinetic and Potential Energy CalculatorKinetic energy from mass and speed, potential energy from mass and height.
- Force and Weight CalculatorF = ma, and what a mass weighs on Earth, the Moon, Mars and Jupiter.
- Work and Power CalculatorWork from force and distance, power from work and time.
- Ideal Gas Law CalculatorSolve PV = nRT for pressure, volume, moles or temperature.
- Wavelength and Frequency CalculatorWavelength, frequency and photon energy of light and radio waves.
- Resistors in Series and Parallel CalculatorTotal resistance of resistors in series or parallel.
- pH CalculatorpH, pOH and hydrogen ion concentration.
- Half-Life CalculatorAmount remaining, time taken or half-life of a decaying substance.
- Projectile Motion CalculatorRange, height and flight time of something launched at an angle.
- Dilution CalculatorC1V1 = C2V2: stock volume, final volume and water to add.
Conversions
Length, weight, volume, pressure, energy and more
- Length ConverterMetres, feet, inches, miles, yards and more, with exact factors.
- Weight and Mass ConverterKilograms, pounds, ounces, stone and tonnes.
- Volume ConverterLitres, UK and US gallons, pints and fluid ounces.
- Area ConverterSquare metres, hectares, acres and square feet.
- Speed ConverterMiles per hour, km/h, metres per second and knots.
- Pressure Converterpsi, bar, kPa, atmospheres and mmHg.
- Energy ConverterJoules, kWh, calories, kilocalories and BTU.
- Power ConverterWatts, kilowatts, horsepower and BTU per hour.
- Time ConverterSeconds, minutes, hours, days, weeks and years.
- Degrees to Radians ConverterDegrees, radians, gradians and turns.
- Data Size ConverterBytes, KB, MB, GB, TB and the binary KiB, MiB and GiB.
Files
PDF, image and CSV tools that never upload
- Combine CSV FilesStack several CSV files into one, matching columns by heading.
- Compress Image to a File SizeSqueeze a photo under 50, 100 or 200 KB, or any size you set.
- JPG, PNG and WebP ConverterConvert images between JPG, PNG and WebP without uploading them.
- CSV Delimiter ConverterChange a CSV's separator between comma, semicolon, tab and pipe.
- CSV Duplicate RemoverRemove duplicate rows from a CSV file. Nothing is uploaded.
- CSV to PDF ReportTurn a CSV or pasted spreadsheet rows into a clean PDF report.
- Image Resizer and CompressorResize and compress JPG, PNG and WebP images on your device.
- JPG to PDF ConverterTurn JPG, PNG and WebP images into one PDF, one per page.
- Merge PDF FilesCombine several PDFs into one, in the order you choose.
- PDF to JPG ConverterTurn PDF pages into JPG or PNG pictures.
- Remove Photo Location Data (EXIF)Strip GPS location and camera details from photos.
- Split PDFPull out pages, split into parts, or one file per page.
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