All calculators

12 free calculators, grouped by what you are trying to work out. Search, or browse by category.

Math

Percentages, percentage change and fractions — the everyday arithmetic people look up most.

Ages, date differences, durations and timesheets, with leap years handled properly.

Tips, discounts and sales tax — the quick sums you do in a shop or at a restaurant table.

Square footage and concrete volume for real projects, in both imperial and metric units.

Aspect ratios and screen dimensions for video, photography and web design.

Age Calculator — Exact age in years, months and days — plus totals and your next birthday.
Aspect Ratio Calculator — Ratio from two dimensions, or the missing dimension from a ratio.
Concrete Calculator — Concrete volume in cubic yards, cubic feet and cubic meters, plus bag counts.
Date Calculator — Days between two dates, or add and subtract days, weeks, months and years.
Discount Calculator — Sale price, money saved and stacked discounts, with optional sales tax.
Fraction Calculator — Add, subtract, multiply and divide fractions and mixed numbers, simplified.
Percentage Calculator — Six percentage calculations in one place, each with the formula and the steps.
Percentage Increase Calculator — Measure the increase or decrease between two values, in either direction.
Square Footage Calculator — Area of rooms, lots and odd shapes in square feet and square meters.
Time Calculator — Add and subtract hours, minutes and seconds, and convert to decimal hours.
Tip Calculator — Tip, total and the per-person split, with the cents adding up exactly.
Work Hours Calculator — Hours worked from clock-in to clock-out, with breaks and overnight shifts.