Convert length, weight, temperature, area, volume and speed with live results. Choose clear metric, US or Imperial units, adjust precision and compare the same quantity in every matching unit.
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Definitions follow NIST SP 811 conversion references ↗. Factors are derived from exact unit definitions, rather than rounded table entries. Approximate displayed results are marked ≈.
All conversion arithmetic runs locally in your browser with no uploads, account or external API. Exact rational factors are applied before display rounding. Inputs and conversion history are not stored. US liquid and Imperial volumes are explicitly distinguished.
53 units across length, mass, absolute temperature, area, volume and speed. Includes metric units, international inches/feet/yards/miles, nautical miles, avoirdupois ounces/pounds, metric/US/Imperial tons, Celsius/Fahrenheit/Kelvin/Rankine, acres/hectares, US liquid/Imperial volumes and knots.
The engine uses exact integer fractions derived from unit definitions before rounding. Choose 2–12 significant digits for display. Approximate display values are marked ≈, and very small or large results use scientific notation. Calculation details show an exact decimal or fraction. This does not improve the accuracy of the original measurement.
This tool converts absolute temperatures and includes the necessary offsets. It rejects values below absolute zero. A temperature difference needs different formulas and is not supported here.
No. They are separate choices. US customary cups mean 8 US fluid ounces. Imperial fluid ounces are also separate. Dry, metric and nutrition-label cup definitions are not included.
Mass and volume cannot be converted without a substance-specific density. This tool only converts within one measurement group. Weight/mass uses mass units, not force.
Signed mathematical values and scientific notation such as −2.5 or 1e6 are accepted using a standard keyboard minus. Use at most 60 digits, 100 characters and an exponent from −100 to 100. Use a decimal dot; commas, unit suffixes, NaN and infinity are rejected. Negative absolute temperatures below 0 K are rejected.
