Free calculators and tools
Every tool gives you the answer, shows the working, and runs in your browser, so nothing you type leaves your device. There are no accounts and no sign-ups.
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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.
- Loan Repayment CalculatorMonthly payment, total repaid and interest on a loan.
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.
- Fuel Cost CalculatorTrip fuel cost from distance, mpg or L/100 km and price per litre.
- Tip and Bill SplitterAdd a tip to a bill and split the total between people.
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.
- Percentage Difference CalculatorPercentage difference and percentage error between two values.
- Weighted Average CalculatorWeighted average of values and their weights, such as course grades.
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.
- SUVAT CalculatorSolve constant-acceleration motion from any three of s, u, v, a and t.
- Specific Heat CalculatorHeat energy, mass or temperature change from Q = mcΔT.
- Hooke's Law CalculatorSpring force, stiffness or stretch from F = kx, plus stored energy.
- Capacitors in Series and ParallelTotal capacitance in series or parallel, with charge and energy.
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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