All Calculators
Every free tool on KwikSum in one place. No sign-up required.
Financial Tools
UK Salary CalculatorTake home pay after income tax, NI, student loan and pension. 2025/26 rates.
Bill Split CalculatorSplit any bill fairly by income or equally between your group.
Tip CalculatorWork out tips at any percentage and split between your group.
Percentage CalculatorFind X% of Y, express X as a percentage of Y, or calculate percentage change.
Loan & Mortgage CalculatorMonthly repayments, total interest and full amortisation schedule.
VAT CalculatorAdd or remove UK VAT at 20%, 5% or any custom rate.
Compound Interest CalculatorSee how savings and investments grow over time with compound returns.
Discount CalculatorFind the sale price and how much you save for any percentage off.
Mortgage CalculatorMonthly repayments, loan-to-value, total interest and a full amortisation schedule.
Stamp Duty CalculatorUK SDLT for standard, first-time and additional buyers (2025/26 bands).
Pension CalculatorProject your pension pot at retirement and the income it could provide.
Savings Goal CalculatorHow long to reach a savings target from deposits and interest.
Inflation CalculatorWhat money will be worth over time and its loss of purchasing power.
Currency ConverterLive exchange rates between GBP, USD, EUR and more.
Everyday & Health Tools
Unit ConverterLength, weight, temperature, volume, area, speed and data storage.
Date CalculatorDays between dates, or add and subtract days, months and years.
BMI CalculatorBody Mass Index in metric or imperial with NHS health categories.
Cooking ConverterConvert cups, tablespoons, grams, millilitres and oven temperatures.
Age CalculatorYour exact age in years, months, days, hours and minutes.
Calorie Calculator (TDEE)Daily calories to maintain, lose or gain weight, from your BMR and activity.
Hours CalculatorHours worked between two times, minus breaks, with decimal hours and pay.
Scientific CalculatorTrigonometry, logarithms, powers, roots, brackets and constants.
Pregnancy Due Date CalculatorEstimate your due date, weeks pregnant and trimester from your last period.
Macro CalculatorSplit a calorie target into protein, carbohydrate and fat grams.
Body Fat CalculatorEstimate body fat percentage with the US Navy tape method.
Ideal Weight CalculatorA healthy weight range for your height, plus the Devine estimate.
Time CalculatorAdd or subtract time, or find the duration between two times.
Fuel Cost CalculatorThe fuel needed and cost of a journey from distance, MPG and price.
Pace CalculatorRunning pace per km and per mile, plus average speed.
Fraction CalculatorAdd, subtract, multiply and divide fractions with a simplified result.
KwikSum offers a growing collection of free online calculators covering financial tools (salary, tax, mortgage, loans, VAT, tips, bill splitting, pension, savings, compound interest, stamp duty, currency and percentages), health tools (BMI, calories, macros, body fat and pregnancy due date) and everyday tools (unit and currency conversion, dates, time, hours, cooking, fuel cost, running pace and more). Every tool works instantly in your browser with no sign-up required.
Popular conversions
Kilograms to PoundsPounds to KilogramsKilograms to StoneStone to KilogramsGrams to OuncesOunces to GramsCentimetres to InchesInches to CentimetresMiles to KilometresKilometres to MilesFeet to CentimetresMetres to FeetMillimetres to InchesLitres to Gallons (UK)Millilitres to Fluid Ounces (UK)Pints (UK) to LitresMiles per Hour to Kilometres per HourKilometres per Hour to Miles per HourMegabytes to GigabytesGigabytes to MegabytesCelsius to FahrenheitFahrenheit to Celsius