Conversion Accuracy Statement

Our commitment

• Conversion factors are taken from primary measurement bodies — BIPM, NIST, ISO and national standards bodies — and never from secondary aggregators.
• Mathematical operations run in IEEE 754 double precision and only the displayed result is rounded.
• Each tool carries a Last reviewed date. Any change to a published standard triggers a re-review.

What can still affect a result

• User input errors — selecting the wrong unit (e.g. US vs UK gallon) is the most common source of incorrect answers.
• Rounding — the displayed value is rounded for readability and may differ from the unrounded value by less than half the last displayed digit.
• Floating-point limitations — extremely large or extremely small magnitudes can introduce small numerical noise.
• Evolving standards — definitions of units occasionally change (notably the 2019 SI redefinition).
• Time-varying data — currency rates and indexed values change continuously.

Where to always verify independently

Independently verify any result that will influence a safety-of-life, regulated, scientific or financial decision. For more detail see the Measurement & Conversion Disclaimer.

Telling us about an inaccuracy

If you believe a conversion is wrong, please use the Corrections Policy. Verified issues are fixed and date-stamped.