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Unit Conversions
Length Converter — Inches, Feet, Yards, Miles & Metric
Switch between US/imperial and metric units the way the rest of the world reads them
Length is the unit conversion Americans bump into most: a recipe gives a pan in centimeters, a treadmill counts in kilometers, a European furniture site lists a shelf in millimeters, and your tape measure still reads in inches and feet. This converter moves any value between the eight units you actually use — inches (in), feet (ft), yards (yd) and miles (mi) on the imperial side, plus millimeters (mm), centimeters (cm), meters (m) and kilometers (km) on the metric side.
The method is simple and exact: every unit is converted to a single base — the meter — and then out to the target unit. The two bridge factors you should memorize are 1 inch = 2.54 cm exactly and 1 mile = 1.609344 km exactly. From those, everything else follows: 1 foot = 12 inches = 0.3048 m, 1 yard = 3 feet = 0.9144 m, and 1 mile = 5,280 feet = 1,760 yards.
Formula: value_in_meters = value × (factor to meters), then result = value_in_meters ÷ (target factor to meters).
Worked example — convert 6 feet to centimeters. First to meters: 6 × 0.3048 = 1.8288 m. Then meters to centimeters: 1.8288 × 100 = 182.88 cm. Sanity check the imperial way: 6 ft = 72 in, and 72 × 2.54 = 182.88 cm. Both routes agree.
Another everyday one — how far is a 5 km race in miles? 5 × (1 ÷ 1.609344) = 3.107 miles, which is why a 5K is often called "a little over three miles."
The common mistake is using rounded, sloppy factors. People remember "1 inch ≈ 2.5 cm" or "1 mile ≈ 1.6 km," and on a marathon or a construction run those roundings pile up into real error. A mile is 1.609344 km, not 1.6 — over a 26.2-mile marathon that shortcut loses about a quarter mile. This tool uses the exact international factors so your answer matches the official ones. Pick a value, a from unit and a to unit, and you'll also get a quick table showing the same length in every common unit at once.
📖 See also: Cups to mL: A Complete Kitchen Conversion Guide
Calculator
Fill in the fields and click "Calculate" for instant results.
📰 Formula
• Convert to meters: meters = value × (factor of the FROM unit) • Convert out: result = meters ÷ (factor of the TO unit) • in = 0.0254 m • ft = 0.3048 m • yd = 0.9144 m • mi = 1609.344 m • mm = 0.001 m • cm = 0.01 m • m = 1 m • km = 1000 m
📰 Formula
• Convert to meters: meters = value × (factor of the FROM unit) • Convert out: result = meters ÷ (factor of the TO unit) • in = 0.0254 m • ft = 0.3048 m • yd = 0.9144 m • mi = 1609.344 m • mm = 0.001 m • cm = 0.01 m • m = 1 m • km = 1000 m
🧪 Worked examples
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Example 2
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Example 3
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Example 4
⚠️ Common mistakes
- Using rounded factors like 1 inch ≈ 2.5 cm or 1 mile ≈ 1.6 km instead of the exact 2.54 and 1.609344.
- Mixing up centimeters and millimeters — there are 10 mm in 1 cm, so the value is 10× different.
- Forgetting that a yard is 3 feet (36 inches), not 4, when stepping between imperial units.
- Reading a metric height like 1.80 m as 1 ft 80 in instead of converting the whole value (≈ 5 ft 11 in).
💡 Tips
- Lock in the two exact bridges — 1 in = 2.54 cm and 1 mi = 1.609344 km — and every other length conversion follows.
- Convert through meters as a single base; it removes guesswork between any two units.
- For a quick gut check, 1 m ≈ 3.28 ft, 1 km ≈ 0.62 mi, and 1 inch ≈ 2.54 cm.
Embed this calculator on your site
Copy the code below and paste it into the HTML of your site or blog.
<iframe src="https://www.calcnimbus.com/embed/length-converter" width="100%" height="500" frameborder="0" style="border:1px solid #eee;border-radius:12px"></iframe>
❓ Frequently asked questions
How many centimeters are in an inch?
Exactly 2.54 cm. The inch is defined as 2.54 centimeters, so 10 inches = 25.4 cm and 1 foot (12 in) = 30.48 cm.
How do I convert miles to kilometers?
Multiply miles by 1.609344. Example: 5 miles × 1.609344 = 8.04672 km. To go back, divide kilometers by 1.609344.
How many feet are in a meter?
1 meter = 3.28084 feet. So 100 meters = 328.084 feet, a touch longer than a football field's 300-foot length.
How do I convert my height from feet and inches to centimeters?
Turn your height into total inches, then multiply by 2.54. A 5 ft 10 in person is 70 inches × 2.54 = 177.8 cm.
How far is a 5K in miles?
A 5K is 5 kilometers, which is 5 ÷ 1.609344 = 3.107 miles. A 10K is 6.214 miles and a half-marathon is 21.0975 km.
How many yards are in a mile?
1 mile = 1,760 yards = 5,280 feet = 63,360 inches. A football field (100 yards) is just under 6% of a mile.
What is the difference between millimeters and centimeters?
There are 10 millimeters in 1 centimeter. So 25 mm = 2.5 cm, and a 12 mm bolt is 1.2 cm — easy to misread if you confuse the two.
Are these conversion factors exact or approximate?
They're exact. Since 1959 the inch is defined as exactly 2.54 cm and the mile as exactly 1,609.344 m by international agreement, so this converter gives official results, not approximations.
How do I convert kilometers to miles in my head?
Multiply kilometers by about 0.62 for a quick estimate. For 80 km/h that's roughly 50 mph. For an exact answer, divide by 1.609344.