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Length Converter

Convert between metres, kilometres, centimetres, millimetres, miles, feet, inches and yards with instant results.

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What this length converter does

This tool converts between the eight length units that appear most often in Pakistani school problems: metres, kilometres, centimetres, millimetres, miles, feet, inches and yards. Enter a value, pick the from and to units, and the result appears instantly as you type. Every conversion goes through the SI base unit (metre) internally, so the numbers are exact where the underlying factors are exact — and the foot, inch, yard and statute mile all have exact metric definitions agreed internationally. The page also includes a full reference table of equivalences, a relative-scale visualization of where each unit sits between the millimetre and the mile, and worked examples spanning classroom, engineering and everyday contexts.

How the conversion works

General length conversion
result = value × factorfrom→m factorto→m

Every length unit is defined by a factor that converts it to metres. To convert from unit A to unit B, multiply the value by A's factor and divide by B's factor. This two-step path through the metre guarantees consistency: converting metres → feet → metres gives the same value you started with, and using any intermediate unit does not change the final result.

Exact conversion factors

  • 1 inch = 0.0254 m (exact)
  • 1 foot = 0.3048 m (exact)
  • 1 yard = 0.9144 m (exact)
  • 1 statute mile = 1609.344 m (exact)
  • 1 km = 1000 m (exact)
  • 1 cm = 0.01 m (exact)
  • 1 mm = 0.001 m (exact)

All imperial length units have been defined exactly in terms of the metre since the 1959 international yard and pound agreement. That means 1 ft = 0.3048 m exactly, not "approximately". Any slight deviation in a computed result is only from the display rounding.

Worked examples

Example 1: 10 metres to feet

  1. 1 m = 1 m; 1 ft = 0.3048 m.
  2. Result = 10 × 1 / 0.3048.
  3. Result = 32.8084 ft.
  4. A 10 m rope is about 32.8 feet long.

Example 2: 100 km to miles

  1. 1 km = 1000 m; 1 mile = 1609.344 m.
  2. Result = 100 × 1000 / 1609.344.
  3. Result = 62.1371 miles.
  4. A 100 km drive is about 62 miles — the standard "100 km" figure used for fuel economy in Pakistan.

Example 3: 30 cm to inches

  1. 1 cm = 0.01 m; 1 in = 0.0254 m.
  2. Result = 30 × 0.01 / 0.0254.
  3. Result = 11.8110 inches.
  4. A 30 cm ruler is just under a foot — 11.8 inches.

Example 4: 6 feet (human height) to metres

  1. 1 ft = 0.3048 m.
  2. Result = 6 × 0.3048.
  3. Result = 1.8288 m.
  4. A person 6 feet tall is 1.83 metres — the practical conversion for BMI or medical charts.

Example 5: 1 mile to feet

  1. 1 mile = 1609.344 m; 1 ft = 0.3048 m.
  2. Result = 1609.344 / 0.3048.
  3. Result = 5280 feet.
  4. The classic "5280 feet in a mile" — worth memorising.

Example 6: 500 mm to cm

  1. 1 mm = 0.001 m; 1 cm = 0.01 m.
  2. Result = 500 × 0.001 / 0.01.
  3. Result = 50 cm.
  4. 500 mm is exactly half a metre — a common conversion in carpentry.

Example 7: 5 km to centimetres

  1. 1 km = 1000 m; 1 cm = 0.01 m.
  2. Result = 5 × 1000 / 0.01.
  3. Result = 500,000 cm.
  4. A 5 km race is 500,000 cm — this huge number shows why choosing the right unit matters for readability.

Example 8: 2 yards to inches

  1. 1 yd = 0.9144 m; 1 in = 0.0254 m.
  2. Result = 2 × 0.9144 / 0.0254.
  3. Result = 72 inches.
  4. Exactly 72 inches — because 1 yard = 3 feet = 36 inches exactly.

Relative scale of length units

Length units span an enormous range — from millimetres (thickness of a coin) to kilometres (distance between cities). This visualization shows roughly where each unit sits on that spectrum, helping you choose the right unit for the right quantity.

Full reference table

These are the exact equivalences for every unit pair in the converter. Use this table for quick mental estimates or to verify a computed value.

Unit In metres In feet In inches
1 mm0.0010.003280.03937
1 cm0.010.032810.39370
1 m13.2808439.3701
1 km10003280.8439370.1
1 in0.02540.083331
1 ft0.3048112
1 yd0.9144336
1 mile1609.344528063360

The three "special" values in this table are worth remembering: 5280 feet in a mile, 12 inches in a foot, and 3 feet in a yard. These three imperial relationships are defined without any metric reference and form the imperial system's internal logic.

Common mistakes to avoid

  • Confusing statute miles with nautical miles. A statute mile is 1609.344 m; a nautical mile is 1852 m exactly. Aviation and marine problems use nautical miles, road distances use statute miles. The difference is about 15%, which is far too large to ignore.
  • Assuming all "miles" are the same. Historically, several different mile definitions existed, and some countries still use regional variations for specific purposes. Modern schooling uses the international statute mile = 1609.344 m. Check the context.
  • Mixing up feet and inches when reading human heights. "6 feet 2 inches" is not 6.2 feet — it is 6 + 2/12 = 6.1667 feet. When converting a mixed feet-and-inches height to metres, add the inch portion as a fraction of a foot first.
  • Forgetting that area and volume conversions square and cube the linear factor. 1 m² = 10,000 cm², not 100 cm². 1 m³ = 1,000,000 cm³, not 1000 cm³. Length conversions are linear; area and volume conversions are not.
  • Rounding intermediate results. Keep full precision through the conversion and round only at the final display. Rounding at each step can shift the last significant digit or two, which matters for engineering.
  • Assuming "1 km = 0.6 miles" is exact. It is a useful mental shorthand, but the exact factor is 0.621371. For a rough estimate 0.6 is fine; for exam answers, use 0.621 or the exact value.
  • Using the wrong centimetre-to-inch direction. Inches are larger than centimetres. 1 inch = 2.54 cm. So 30 cm is about 11.8 inches — less than 30. If your result is larger than the input when converting cm → in, you have the direction backwards.

FAQ

How do I convert metres to feet?

Multiply metres by 3.28084. For example, 10 m = 32.8084 ft. One foot is defined exactly as 0.3048 metres, so the reverse conversion is metres = feet × 0.3048. Both factors are exact because the foot was defined in terms of the metre in 1959.

How do I convert kilometres to miles?

Multiply kilometres by 0.621371. For example, 5 km = 5 × 0.621371 = 3.10686 miles. One statute mile is defined exactly as 1609.344 metres, which is about 1.609 km. Do not confuse statute miles with nautical miles, which are 1852 m exactly.

How do I convert centimetres to inches?

Multiply centimetres by 0.393701. For example, 30 cm = 30 × 0.393701 = 11.811 inches. One inch is defined exactly as 2.54 cm. The reverse is inches × 2.54 = centimetres.

What is the difference between a statute mile and a nautical mile?

A statute mile is 1609.344 metres and is used for road distances. A nautical mile is exactly 1852 metres and is used in aviation and marine navigation. The two differ by about 15%. Problems that mention knots, ports, or latitudes almost always intend nautical miles; road distances use statute miles.

How many feet are in a mile?

Exactly 5280 feet. This is because one mile is 1609.344 m, and 1609.344 ÷ 0.3048 = 5280. This is a useful memory anchor: the number 5280 appears in the mile-to-feet conversion and nowhere else in the length converter.

Why does the converter show very large numbers in scientific notation?

For values that are extremely small or extremely large — like nanometres in miles, or light-years in millimetres — the result is displayed in scientific notation (like 3.2e-13) to keep it readable. The full precision is preserved; only the display format changes.

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Practice unit conversions with our Class 9 notes and Class 10 notes, and track term progress with the free Student Portal.

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