# Length Converter > Length converter: miles, kilometers, meters, feet, inches, yards. Free length converter with the formula shown - runs entirely in your browser, no signup. - **Canonical URL:** https://boringtoolskit.com/length-converter/ - **Category:** Converters - **Evidence level:** authored-methodology - **Reviewed:** 2026-09-20 - **Last verified:** 2026-10-12 - **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request. ## How it works Value x (metres per source unit) / (metres per target unit), using exact factors: mile 1609.344, foot 0.3048, inch 0.0254, yard 0.9144, nautical mile 1852. ## Worked example 1 foot = 12 inch · 1 meter = 1.094 yard · 1 mile = 1.609 kilometer ## Assumptions - Inputs are treated as exact decimal values. - Standard (not historical or survey) unit definitions are used. - The calculation uses the factors at the precision shown in the formula panel; rounding beyond that is display-only and adds no accuracy. ## Common questions ### Why convert through meter instead of directly? Routing every unit through a single base (meter) means each unit needs only one exact factor against the standard, and any pair combines cleanly. Direct pair factors drift apart over time in hand-maintained tables; a base-unit graph cannot. ### Where do these exact factors come from? From published standards (NIST: The International System of Units (SI), SP 330). Units like the inch are defined exactly (1 in = 2.54 cm since 1959), so conversions between standard units are exact, not approximate. ### How many decimal places should I trust? The math is exact to the precision shown. The practical limit is your input: a tape measure is only good to ~1 mm and a kitchen scale to ~1 g, so 3–4 significant figures already exceeds the measurement's own accuracy. ## Sources - [The International System of Units (SI), SP 330](https://www.nist.gov/pml/special-publication-330) --- *Local planning estimate. Verify current terms, rates, and policies before acting.*