Want to learn more about our project and why we created Simple Calculator? Visit our About Us page.
Find free online calculators for finance, maths, health, science, conversions and everyday use. Choose a category below to get started. All calculators are fast, mobile-friendly and require no registration.
Free everyday calculators for quick maths, percentages, discounts, averages, dates, countdowns and other daily tasks. Perfect for shopping, budgeting, planning and solving common calculations in seconds.
Quickly calculate percentages and changes.
Perform addition, subtraction, multiplication and division.
Work out sale prices and savings during promotions.
Calculate gratuities and split restaurant bills.
Simplify and scale ratios for recipes, maths and business.
Calculate mean, median and mode instantly.
Find the number of days, months or years between two dates.
Count business days while excluding weekends and holidays.
See exactly how much time remains until any future date or event
Plan your finances with free UK financial calculators for mortgages, loans, VAT, salaries, stamp duty and compound interest. Accurate tools designed to help with budgeting, borrowing and smarter financial decisions.
Estimate repayments and interest for personal loans.
Calculate monthly payments and full amortization.
Estimate how much you could borrow based on income, deposit and expenses.
Calculate interest savings and discover how extra payments could shorten your mortgage term.
Add or remove VAT instantly (UK rates).
Estimate your take-home salary after tax.
Calculate property tax in the UK.
Calculate savings growth and investment returns.
Estimate your credit score based on utilization, payment history, and credit age.
Estimate income tax, National Insurance and take-home pay for sole traders and freelancers.
Estimate monthly repayments, interest and the total cost of financing a vehicle.
Estimate annual and monthly student loan repayments for Plan 1, Plan 2, Plan 4, Plan 5 and Postgraduate loans.
Calculate fuel costs, mileage, EV running costs, tyre sizes, wheel offsets, gear ratios, power-to-weight, horsepower and torque conversions. Free automotive tools for cars, motorcycles and electric vehicles.
Estimate fuel costs for any journey using distance, fuel efficiency and fuel prices.
Estimate fuel costs and HMRC mileage claims for business and personal journeys.
Compare fuel and electricity costs to see how much you could save by driving an electric vehicle.
Calculate HP per tonne and kW per tonne to compare the performance of cars, motorcycles, and electric vehicles.
Convert instantly between Horsepower (HP), Metric Horsepower (PS), and Kilowatts (kW).
Convert torque between Newton metres (Nm), pound-feet (lb-ft), pound-inches (lb-in), and kilogram-metres (kg·m).
Compare tyre sizes, rolling diameter, sidewall height, circumference, and speedometer difference.
Compare wheel width, offset (ET), and tyre fitment to see inner and outer clearance changes.
Calculate gear ratios, final drive ratios, wheel speed, and torque multiplication for any drivetrain.
Convert units instantly with free converters for temperature, weight, length, speed, volume, pressure, fuel economy and time. Fast and accurate tools for everyday use, travel, engineering and education.
Convert seconds, minutes, hours, days, weeks and years instantly.
Convert kilograms, pounds and stones (kg, lb, st).
Convert centimetres, metres, inches and feet.
Convert mph, km/h, knots and metres per second.
Convert MPG to L/100km and litres per 100 kilometres.
Convert Celsius, Fahrenheit and Kelvin temperatures.
Convert litres, UK gallons and US gallons.
Convert PSI, Bar and kilopascals (kPa).
Convert metric and imperial length units.
Convert square metres, square feet, acres and hectares.
Track your health with calculators for BMI, body fat, calorie needs, ideal weight and other fitness metrics. Simple tools to support healthy living, nutrition and personal wellness goals.
Check your body mass index instantly.
Calculate exact age in years, months, days.
Estimate your child's or your future height.
Estimate your daily calorie needs.
Estimate your body fat percentage.
Calculate your healthy weight range.
Solve advanced mathematical problems using scientific calculators for trigonometry, logarithms, powers, roots, factorials and geometry. Ideal for students, engineers and everyday problem solving.
Find the sine of any angle in degrees or radians with instant precision.
Calculate cosine values and explore the unit circle.
Calculate tangent values for any angle quickly and accurately.
Find square roots with high precision and instant results.
Calculate cube roots for positive and negative numbers.
Raise numbers to any power using exponents.
Calculate logarithms, natural logs and exponential values.
Compute factorials for mathematics, probability and combinatorics.
Pythagorean Theorem Calculator – Find the Hypotenuse
Simple Calculator is an independent family-run project created by Thomas and his son Kris. What began as a collection of practical tools for everyday use has grown into a library of free online calculators covering finance, mathematics, health, science, time, and unit conversions. Every calculator is designed to be fast, accurate, and easy to use on desktop, tablet, and mobile devices, with no registration or unnecessary complexity.
Whether you are calculating mortgage repayments, salary after tax, VAT, fuel costs, percentages, BMI, scientific formulas, or unit conversions, our goal is to provide reliable tools that help students, families, professionals, and businesses solve everyday calculations quickly and confidently.
We believe useful online tools should be simple, fast, and accessible to everyone. Our mission is to build practical calculators that help people make informed decisions, save time, and solve everyday problems without unnecessary complexity.
From quick percentage calculations to mortgage planning, salary estimates, scientific formulas, and health metrics, every calculator is created with ease of use and accuracy in mind.
Want to learn more about our project and why we created Simple Calculator? Visit our About Us page.
Some of our most frequently used tools include the Salary Calculator, VAT Calculator, Mortgage Calculator, Loan Calculator, Fuel Cost Calculator, Stamp Duty Calculator, and many other finance, health, scientific, and conversion calculators. New calculators are added regularly as the project continues to grow.
Quickly calculate estimated take-home pay.
Quickly calculate mortgage costs.
Quickly calculate VAT and total price.
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Browse essential calculators for finance, everyday maths, and scientific calculations — all in one place.
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Built for personal use, now shared for free — simple, fast, and private calculators for everyone.
Last Updated: August 2026