Unit Converter
Convert length, weight, and temperature units instantly, for free.
This tool runs entirely in your browser. Your files are never uploaded to a server.
1 m = 39.3700787402 in
What this tool does
Convert common length, mass, and temperature units in either direction. Supported length units run from millimeters to miles, mass units from milligrams to pounds, and temperature units cover Celsius, Fahrenheit, and kelvin.
How to use it
Choose a category, enter a finite number, and select source and destination units. The result updates immediately. Preserve more source digits when measurement uncertainty matters and round only at the end of a larger calculation.
Worked examples
One meter equals approximately 39.3700787402 inches, one avoirdupois pound equals exactly 453.59237 grams, 32 °F equals 0 °C, and 0 K equals −273.15 °C. These values are covered by automated tests.
Method and formulas
Length values pass through meters and mass values through grams using fixed conversion factors. Temperature first converts to Celsius: °C = (°F − 32) × 5/9 or °C = K − 273.15, then applies the inverse formula.
Interpreting precision
The interface displays at most ten fractional digits, so the visible value may be rounded even when a factor is exact. Input precision and measurement uncertainty still limit the meaningful precision of any converted result.
Limitations and standards
The tool uses the international inch, yard, avoirdupois ounce, and pound, not historical or specialized variants. Temperatures below absolute zero are rejected. It does not currently cover area, volume, pressure, energy, or cooking measures.
Privacy and sources
Conversions run locally in the browser and no entered value is uploaded. Exact customary factors follow NIST references, while the Celsius–kelvin offset follows the current BIPM SI Brochure; review these sources when standards change.
Frequently Asked Questions
- Which units can I convert?
- Length (millimeters, centimeters, meters, kilometers, inches, feet, yards, miles), weight (milligrams, grams, kilograms, ounces, pounds), and temperature (Celsius, Fahrenheit, Kelvin) — switch categories with the toggle.
- How accurate are the displayed conversions?
- The engine uses standard factors and the interface shows up to ten fractional digits. Display rounding, the precision of your input, and the uncertainty of the original measurement determine how many digits are meaningful.
- Is this converter free and private?
- Yes. It runs entirely in your browser with no data sent to a server, and it's completely free with no sign-up required.