Unit Conversion Calculators

About our unit conversion calculators

Every converter on GuideCalculator applies the internationally-standardised conversion factor for its unit pair and rounds only at the display step. The math under the hood is identical to what you'd compute in a spreadsheet or a scientific calculator — there's no estimation or approximation involved.

All conversions support two-way operation: tap the swap icon between the unit selectors to reverse the direction. Every page also includes a quick-reference table of common values (1, 5, 10, 50, 100, 500, 1000) so you can verify your conversion at a glance.

How conversion factors work

For linear units (length and weight), conversion is a single multiplication by a fixed factor — for example, 1 inch is exactly 2.54 centimetres, so any inch value times 2.54 gives the equivalent in centimetres. For temperature, the relationship is affine (it includes an offset), so the formula has two terms — for example, °F = (°C × 9/5) + 32.

Our converters use NIST-standard factors, which are the same values used by metrology institutes worldwide. If you've ever seen slightly different values on other websites, it's usually because they round earlier in the calculation — our approach preserves precision until the very end.