Calculators

Calculate percentages, discounts, dates, ages and unit conversions. Use the examples and explanations to check your inputs and results.

Percentage Calculator

Calculate percentages and percentage changes.

Aspect Ratio Calculator

Calculate ratios and matching dimensions.

Unit Converter

Convert length, mass, temperature, volume, area, speed and data units locally.

Age Calculator

Calculate calendar age in years, months and days on a date you choose.

Date Calculator

Find the difference between dates or add and subtract calendar time.

Tip Calculator

Calculate a tip, total bill and per-person amounts without choosing a currency.

Percentage Change Calculator

Compare an original and a new value to find the percentage change and absolute difference.

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File Size Converter

Convert bytes, KB, MB, GB and TB to binary KiB, MiB, GiB and TiB without uploading a file.

DPI / PPI Calculator

Calculate screen pixel density from resolution and diagonal size, or print density from pixels and inches.

Choose the right tool

Choose the calculator for the question you need to answer. Percentage change compares an old value with a new one; a discount reduces a price. Check units and date inputs before relying on a result.