Everyday Tools
The common lookups: converting between units, working out a percentage, counting words against a limit, or checking a date difference. These are deliberately simple and fast to load, because the whole point is getting an answer in a few seconds and moving on.
All everyday tools
- Percentage CalculatorCalculate percentages, percentage change, and one number as a percentage of another.
- Word CounterCount words, characters, sentences and paragraphs in text as you type.
- Age CalculatorCalculate exact age or the interval between two dates in years, months and days.
- Unit ConverterConvert between metric and imperial units of length, weight, volume, area and temperature.
How these are grouped
- Converters
- Units, measures and formats.
- Calculators
- Percentages, dates and general arithmetic.
- Text
- Counting and analysing written content.
Choosing the right tool
The Unit Converter and Percentage Calculator both do quick arithmetic but on different kinds of question: use the converter when the underlying quantity is the same and only the unit changes (kg to lb, °C to °F), and the percentage calculator when the relationship itself is what you're solving for (what percentage is X of Y, or what is X% of Y). The Age Calculator and Word Counter are narrower tools built around one specific, frequently repeated task each.
Common mistakes
- Using a rounded conversion factor (like 2.2 lb per kg) for anything consequential — the exact, internationally defined factor (0.45359237 kg per lb) avoids an error that compounds across repeated conversions or large quantities.
- Applying a temperature conversion as a straight ratio — °C and °F don't share a zero point, so temperature needs the offset formula (°F = °C × 9/5 + 32), not just a multiplier.
- Mixing up US and UK versions of a unit that shares a name — a US gallon and a UK imperial gallon differ by about 20%, and no amount of decimal precision fixes an error caused by converting the wrong one.
- Confusing a percentage change with a percentage point change — a rate moving from 5% to 7% is a 2 percentage-point increase, but a 40% relative increase, and the two get reported interchangeably in ways that materially change what a figure means.
A short example
Converting 70 kg to pounds for a shipping label, and separately calculating what percentage a £15 discount is on a £60 item.
70 kg converts to 154.32 lb using the exact factor (154.0 using the common '×2.2' shortcut — small here, but the same shortcut applied to a much larger shipment produces a discrepancy worth catching before it reaches a customs form). The discount question is separate: £15 ÷ £60 = 25%, a straightforward percentage-of calculation rather than a conversion at all.