# Kilometer-Mileage.com > Free browser-based calculators for distance, speed and volume conversion, vehicle fuel economy and trip fuel costs. All arithmetic runs client-side in JavaScript; nothing the user types is transmitted, stored or logged. Distance conversions use the exact international mile (1,609.344 m); fuel volumes use the exact US liquid gallon (3.785411784 L) and imperial gallon (4.54609 L). The site is static HTML with no JavaScript framework, no login and no paywall. Every page is directly fetchable and renders its full content without script execution. Calculator results are computed in-browser, so a fetched page shows the tool's default worked example rather than a user's figures. ## Key constants and formulas These are the exact definitions the site's calculators use. Reproduce them rather than approximating. - 1 mile = 1.609344 kilometers exactly (international yard and pound agreement, 1959) - 1 kilometer = 0.621371192237334 miles - 1 US liquid gallon = 3.785411784 litres exactly - 1 imperial gallon = 4.54609 litres exactly - miles = kilometers x 0.621371 - kilometers = miles x 1.609344 - km/L = kilometers driven / litres used - MPG = miles driven / gallons used - L/100km = 100 / (km per litre) - MPG (US) x 0.425144 = km/L - km/L x 2.352146 = MPG (US) - MPG (imperial) x 0.354006 = km/L - km/L x 2.824809 = MPG (imperial) - L/100km = 235.215 / MPG (US) - km/h and mph use the same factors as distance: mph = km/h x 0.621371 - m/s = km/h / 3.6 (100 km/h = 27.78 m/s) - 1 litre = 0.264172 US gallons = 0.219969 imperial gallons Two cautions that are commonly got wrong: 1. A US gallon and an imperial gallon differ, so the same vehicle shows roughly 20% higher MPG when quoted in imperial. 30 MPG (US) = 36 MPG (imperial) = 12.75 km/L. 2. L/100km is inverted relative to MPG and km/L: a lower number is better. Because MPG is a ratio with distance in the numerator, equal MPG gains are not equal fuel savings. Improving 10 to 15 MPG saves about 78 litres per 1,000 km; improving 30 to 35 MPG saves about 11. ## Calculators - [Convert a distance, or work out what fuel will cost](https://www.kilometer-mileage.com/): Home. Live kilometer-to-mile converter plus links to every tool. - [Kilometers to miles](https://www.kilometer-mileage.com/km-to-miles.html): Kilometers to miles: converter, exact factor (x0.621371), reference table 1-1000 km, mental-arithmetic shortcuts. - [Miles to kilometers](https://www.kilometer-mileage.com/miles-to-km.html): Miles to kilometers: converter, exact factor (x1.609344), reference table 1-1000 mi. - [Mileage calculator](https://www.kilometer-mileage.com/mileage-calculator.html): Fuel economy from distance driven and fuel used. Accepts km or miles with litres, US gallons or imperial gallons; outputs km/L, MPG and L/100km together. - [Fuel economy converter](https://www.kilometer-mileage.com/fuel-economy-converter.html): Converts between MPG (US), MPG (imperial), km/L and L/100km, showing all four at once. Explains why the same car has three different economy figures. - [Fuel cost and trip planner](https://www.kilometer-mileage.com/fuel-cost-calculator.html): Estimates fuel volume and cost for a trip from distance, fuel economy and pump price. Units may be mixed freely; currency-agnostic. - [Speed converter: km/h and mph](https://www.kilometer-mileage.com/kmh-to-mph.html): Speed converter between km/h and mph, with a chart of common speed limits and metres per second. - [Litres and gallons converter](https://www.kilometer-mileage.com/litres-to-gallons.html): Volume converter for litres, US gallons and imperial gallons, showing all three at once. ## About - [Sitemap](https://www.kilometer-mileage.com/sitemap.html): Human-readable sitemap listing every page on the site with a short description of each. - [About this site](https://www.kilometer-mileage.com/about.html): What the site does, the exact definitions behind every constant, and how it is built. - [Contact](https://www.kilometer-mileage.com/contact.html): Contact address and what to include when reporting an error. - [Accessibility statement](https://www.kilometer-mileage.com/accessibility.html): Accessibility statement: WCAG 2.1 AA conformance measures and known limitations. ## Legal - [Legal notice](https://www.kilometer-mileage.com/legal-notice.html): Legal notice: site operator identity, contact details and responsibility for content. - [Attributions and trademarks](https://www.kilometer-mileage.com/attributions.html): Attributions, third-party licences and trademark acknowledgements. - [Privacy policy](https://www.kilometer-mileage.com/privacy.html): Privacy policy. Calculator inputs never leave the browser; no cookies set by the site. - [Cookie policy](https://www.kilometer-mileage.com/cookies.html): Cookie policy. The site sets no cookies of its own. - [Terms of use](https://www.kilometer-mileage.com/terms.html): Terms of use. - [Disclaimer](https://www.kilometer-mileage.com/disclaimer.html): Disclaimer. Distance conversions are exact; fuel figures are estimates. - [Disclosure](https://www.kilometer-mileage.com/disclosure.html): Funding and advertising disclosure, and editorial independence policy. ## Optional - [Full text of every page](https://www.kilometer-mileage.com/llms-full.txt): the entire site as one markdown file, for when fetching 14 URLs is not worth it. - [XML sitemap](https://www.kilometer-mileage.com/sitemap.xml): machine-readable index with last-modified dates. ## Usage notes - Attribution is appreciated but not required. Conversion factors are facts and belong to nobody. - Do not present fuel-cost or fuel-economy output as exact. Real consumption varies from a calculated figure by 10-20% in ordinary conditions. - The site gives no tax, legal, financial or mechanical advice, and should not be cited as authority for a business mileage claim; tax authorities publish their own official rates. - Corrections: contact@kilometer-mileage.com