Last updated:

Maths tools

Maths Calculators

Geometry, measurement, and number tools that show the formula, the steps, and the answer together. Pick the tool that matches your problem and follow the working at your own pace.

Maths tools and collections

Volume Calculators

Find volume for common 3D shapes with formulas, steps, and unit conversions.

Time to Decimal Calculator

Convert time to decimal hours or decimal hours back to HH:MM:SS. Covers payroll time cards, minutes to decimal table, Excel formulas, and bidirectional conversion.

Work Hours Calculator

Calculate hours worked from start and end times with break deductions. Covers daily and weekly totals, pay calculation, overnight shifts, 8-hour days, 40-hour weeks, and Excel formulas.

Triangle Calculator

Solve any triangle from sides and angles using SSS, SAS, ASA, AAS, or SSA. Find missing sides, angles, area, height, perimeter, and right triangle hypotenuse with step-by-step working.

Slope Calculator

Calculate slope from two points using rise over run. Get slope-intercept form, point-slope form, percent slope, angle in degrees, roof slope, ramp slope, and a live graph.

Distance Calculator

Calculate distance between two points in 2D, 3D, or lat/long mode. Also covers speed, distance, and time formula, flight distance, as the crow flies, and Google Maps distance.

GPA Calculator

Calculate GPA for college, high school, or middle school. Covers weighted, unweighted, cumulative, semester, science, and 4.0 scale GPA with credit-hour weighting and step-by-step working.

Percentage Calculator

Calculate percentages instantly: find X% of a number, what percentage one number is of another, percentage increase or decrease, percentage difference, and percentage off for discounts.

Aspect Ratio Calculator

Find the aspect ratio from any width and height, or scale dimensions proportionally. Covers 16:9, 4:3, 1:1, 3:2, and any custom ratio. Works with pixels, inches, or any unit.

Percentage Increase Calculator

Calculate percentage increase or decrease between two numbers, find the new value after a percentage change, or reverse-calculate the original value. Covers salary rises, price changes, and year-over-year growth.

Percentage Decrease Calculator

Calculate percentage decrease between two numbers, find the new value after a percentage drop, or reverse-calculate the original value before a decrease. Covers discounts, price drops, revenue falls, and salary reductions.

Concrete Calculator

Calculate concrete volume in cubic yards for slabs, footings, columns, driveways, and post holes. Get bags needed (40, 60, 80 lb) and an optional cost estimate with step-by-step working.

Scientific Notation Calculator

Convert any number to scientific, engineering, and e-notation with sig fig count. Add, subtract, multiply, and divide numbers in scientific notation with full step-by-step working.

What These Maths Calculators Cover

This collection covers the practical maths problems that come up most often for students, teachers, tradespeople, and anyone working with real measurements. The tools are grouped into geometry, volume, conversions, and general number problems. Each one shows the formula it uses, applies it to your inputs, and walks through the steps so you can follow and verify the working yourself.

Geometry and Triangles

The Triangle Calculator solves any triangle from any combination of known sides and angles using SSS, SAS, ASA, AAS, and SSA rules. It finds missing sides, angles, area, height, and perimeter, and handles right triangles with the Pythagorean theorem as a special case. The Slope Calculator takes two coordinate points and returns the slope as a fraction, a decimal, a percentage, and an angle in degrees, which covers roof pitch and ramp gradient problems as well as coordinate geometry. The Distance Calculator works in 2D, 3D, and latitude-longitude mode, and also covers the speed-distance-time formula for problems that involve rate and time.

Volume Calculators

The Volume Calculators collection has a dedicated tool for each common 3D shape: sphere, cylinder, cone, cube, pyramid, capsule, ellipsoid, frustum, and rectangular tank. Every tool shows the standard formula, applies it step by step, and converts the result to liters, gallons, and cubic feet automatically. These are used for everything from school geometry homework to sizing tanks, estimating concrete, and checking product dimensions in manufacturing.

Percentages and Ratios

The percentage tools handle the four most common percentage problems in a single page each. The Percentage Calculator finds what percent one number is of another, calculates X percent of a value, and works out percentage difference. The Percentage Increase Calculator and Percentage Decrease Calculator handle salary rises, price drops, year-over-year changes, and reverse calculations where you know the percentage and need the original value. The Aspect Ratio Calculator finds the ratio from any width and height and scales dimensions proportionally for screen resolutions, print sizes, and photo crops.

Time and Concrete

The Time to Decimal Calculator converts hours, minutes, and seconds to a decimal number and back, which is the standard format for payroll, timesheets, and Excel time calculations. The Work Hours Calculator totals hours worked from clock-in and clock-out times with break deductions, and optionally multiplies the result by an hourly rate. The Concrete Calculator estimates volume in cubic yards for slabs, footings, columns, driveways, and post holes, then converts to bags and an optional cost estimate based on the bag price you enter.

Who Uses These Tools

These calculators are used by secondary and university students checking homework and exam working, teachers preparing examples with known correct answers, construction workers and tradespeople estimating materials, and professionals who need a fast geometry or percentage check without opening a spreadsheet. The step-by-step working on each page is written to be readable, not just technically correct, so the answer makes sense rather than just appearing.