All calculators
Every calculator on 1plus1, grouped by topic. Each one shows the formula it uses, the steps it took and the assumptions behind the result.
Mortgage Work out a mortgage payment, the total interest and the full amortisation schedule, with extra payments and taxes included. Loan Work out the payment, total interest and real annual rate of a personal or car loan, fees and extra payments included. Compound interest See what an investment grows to with compound interest, with or without regular contributions, at any compounding frequency. Savings Project what your savings will grow to, work out the deposit a goal needs, or find how long that goal will take.
Mathematics
Percentages, fractions, equations and numbers Percentage Work out a percentage of a number, a share, a percentage change, or add and subtract a percentage — with every step shown. Fractions Add, subtract, multiply and divide fractions, reduce them to lowest terms, and convert between fractions and decimals. Ratios Simplify a ratio, share a total between any number of parts, or solve a proportion by cross multiplication. Statistics Paste a series of numbers and read its mean, median, spread, quartiles, skewness and outliers at a glance. Discount Find the sale price, the percentage off, or the price before the discount — including stacked offers and sales tax.
Date and time
Age, durations, deadlines and hours workedUnit conversion
Length, weight, volume, temperature, energy and more Unit converter Convert between metric, imperial and US units across fourteen categories — length, weight, volume, speed, energy and more. Temperature Convert between Celsius, Fahrenheit, Kelvin and Rankine, with the formula, the substitution and a table of familiar reference points. Fuel cost Work out what a trip will cost in fuel, or find your car’s real consumption from a fill-up, in litres or gallons.
Area Find the area and perimeter of nine common shapes, entering each dimension in whatever unit you have to hand. Volume Find the volume and capacity of eight solids, from a packing box to a cylindrical tank, in any unit you need. Right triangle Solve a right triangle from any two measurements: the missing side, both angles, the area and the perimeter.
Construction
Concrete, paint, materials and surfaces Area Find the area and perimeter of nine common shapes, entering each dimension in whatever unit you have to hand. Volume Find the volume and capacity of eight solids, from a packing box to a cylindrical tank, in any unit you need. Right triangle Solve a right triangle from any two measurements: the missing side, both angles, the area and the perimeter.
Everyday life
Tips, discounts, fuel and splitting the bill Tip Work out a tip, split the bill between any number of people, and round the total or the share to a clean amount. Discount Find the sale price, the percentage off, or the price before the discount — including stacked offers and sales tax. Fuel cost Work out what a trip will cost in fuel, or find your car’s real consumption from a fill-up, in litres or gallons.
20 calculators