Imperial to Metric Conversion Chart
Printable reference table for common imperial and metric units across length, weight, volume and area.
Conversion Reference Table
Look up the most common imperial units and their metric equivalents. Use the alternative column for everyday scales (cm, kg, liters).
| Category | Imperial / US | Metric | Alternative |
|---|---|---|---|
| Length | 1 inch (in) | 25.4 mm | 2.54 cm |
| Length | 1 foot (ft) | 304.8 mm | 30.48 cm |
| Length | 1 yard (yd) | 0.9144 m | 91.44 cm |
| Length | 1 mile (mi) | 1.609 km | 1609 m |
| Weight | 1 ounce (oz) | 28.35 g | 0.02835 kg |
| Weight | 1 pound (lb) | 453.59 g | 0.4536 kg |
| Volume | 1 US gallon | 3.785 L | 3785 ml |
| Volume | 1 US quart | 0.946 L | 946 ml |
| Volume | 1 US cup | 236.6 ml | 0.237 L |
| Area | 1 sq ft | 0.0929 m² | 929 cm² |
| Area | 1 acre | 4047 m² | 0.405 ha |
| Temperature | °F to °C | (°F - 32) × 5/9 | See temperature converters |
1 inch is exactly 25.4 mm. US liquid gallons differ from UK imperial gallons. For temperature, use our dedicated Fahrenheit to Celsius converters.
Online Converters
For exact values, fractions of an inch, or custom amounts, use our dimension converters:
Table of Contents
The History of Measurement Systems
Imperial and metric units evolved from different needs: trade, construction, science and everyday life. A conversion chart bridges both worlds when you read US product labels, UK recipes, or international specifications.
The Imperial System
The imperial system grew in Britain and spread to the United States and former colonies. It uses familiar but non-decimal relationships: 12 inches per foot, 3 feet per yard, 16 ounces per pound, and US customary volume units (cups, pints, gallons) that differ slightly from UK imperial volumes.
Where imperial units still appear:
- US construction, lumber and real estate (feet, inches, square feet)
- Cooking and packaging in the US (cups, ounces, pounds)
- UK road signs (miles) and some retail (pints of beer)
- Aviation and maritime charts in some regions
The Metric System
The metric system (SI) is decimal-based: millimeters, centimeters, meters, kilometers for length; grams and kilograms for mass; liters for volume. Nearly all countries use it officially, which makes charts like this essential when working across borders.
Why conversion charts matter
Mistakes between imperial and metric units have caused costly errors in engineering and aviation. A printed or on-screen chart reduces guesswork; online converters give exact results for non-standard values.
Mars Climate Orbiter (1999)
A mix of metric and imperial units in navigation software led to loss of the spacecraft.
Gimli Glider (1983)
Fuel was calculated in pounds instead of kilograms, leaving an airliner without enough fuel mid-flight.
How to Use This Conversion Chart
Use this table for quick lookups when reading US or UK specifications, blueprints, recipes or product labels. Follow these steps for best results:
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1Find the category (length, weight, volume, area or temperature).
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2Locate the imperial unit in the second column.
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3Read the metric equivalent, or use the alternative column if that scale is more convenient.
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4For values not in the table, open one of our online converters for an exact calculation.
1 inch = 25.4 mm (exact)
1 foot = 0.3048 m (exact)
1 pound = 0.453592 kg
1 US gallon = 3.78541 L
Common Examples
Example 1 6 feet to meters
6 ft x 0.3048 = 1.8288 m
Example 2 2 pounds to kilograms
2 lb x 0.4536 = 0.907 kg
Example 3 1 US gallon to liters
1 gal = 3.785 L
Example 4 100 square feet to m²
100 sq ft x 0.0929 = 9.29 m²