About this calculator
This length calculator converts between the seven most common length units: inches, feet, yards, miles, centimeters, meters, and kilometers. Enter a value in any one field — or combine several, such as 5 feet and 6 inches — and it adds them together and shows the total length in every unit at once.
How to use
Enter a value into any one or more of the fields above (leave the rest blank), then click Calculate to see the total length converted into all seven units. Click Clear to reset every field.
The Formula: Converting Through a Common Base Unit
Rather than storing a separate formula for every possible pair of units, the calculator converts everything through meters as a common base, then converts back out to each display unit:
- Total meters = Σ (value in unit × that unit's meter factor), summed across every field you filled in
- Result in any unit = Total meters ÷ that unit's meter factor
The meter factors the calculator uses are exact, internationally defined values: 1 inch = 0.0254 m, 1 foot = 0.3048 m, 1 yard = 0.9144 m, 1 mile = 1609.344 m, 1 centimeter = 0.01 m, 1 kilometer = 1000 m. Because inches, feet, yards, and miles are all defined as exact multiples of the meter (since the 1959 international yard and pound agreement), every conversion this calculator performs is mathematically exact — there's no approximation error, only rounding in the displayed decimal places.
Worked Example
Suppose you enter 5 in the Feet field and 6 in the Inches field (a height of 5'6"):
- Total meters = (5 × 0.3048) + (6 × 0.0254) = 1.524 + 0.1524 = 1.6764 m
- Back to feet: 1.6764 ÷ 0.3048 = 5.5 ft
- Back to inches: 1.6764 ÷ 0.0254 = 66 in
- To yards: 1.6764 ÷ 0.9144 = 1.8333 yd
- To centimeters: 1.6764 ÷ 0.01 = 167.64 cm
- To miles: 1.6764 ÷ 1609.344 ≈ 0.001042 mi
- To kilometers: 1.6764 ÷ 1000 = 0.001676 km
All seven values represent the exact same physical length — 5 feet 6 inches — just expressed in different units, which is exactly what the calculator's results table shows.
Common Mistakes / How to Interpret the Result
- Filling in more than one field without meaning to add them. The calculator treats every non-empty field as part of a sum — entering both "5" in Feet and "3" in Yards gives you the total of 5 feet plus 3 yards combined, not two independent conversions. Clear the fields between separate conversions unless you specifically want to add lengths together.
- Assuming a US survey foot and an international foot are identical. This calculator uses the international foot (0.3048 m exactly), which is standard for virtually all everyday and engineering use. The US survey foot differs by about 2 parts per million — irrelevant for daily use, but occasionally significant in large-scale land surveying.
- Confusing a nautical mile with a statute mile. This calculator's "miles" field uses the standard statute mile (1,609.344 m), used for road distances. A nautical mile (1,852 m), used in aviation and marine navigation, is about 15% longer and is not one of the seven units offered here.
- Over-trusting displayed precision. The calculator shows up to 6 decimal places for very small results, but your real-world measurement is rarely that precise — round the final answer to match the precision of whatever you originally measured.
Length Conversion Chart: Complete Reference Table
Use the quick-reference tables below to look up any unit pair without opening the calculator. All values are exact per the 1959 international yard agreement (1 inch = 25.4 mm exactly).
All Units Expressed in Meters
| Unit | Symbol | Value in Meters (exact) |
|---|---|---|
| Millimeter | mm | 0.001 m |
| Centimeter | cm | 0.01 m |
| Meter | m | 1 m |
| Kilometer | km | 1,000 m |
| Inch | in | 0.0254 m |
| Foot | ft | 0.3048 m |
| Yard | yd | 0.9144 m |
| Mile | mi | 1,609.344 m |
Most-Searched Conversion Pairs
| From | Equals |
|---|---|
| 1 inch | 2.54 cm |
| 1 foot | 30.48 cm = 0.3048 m |
| 1 yard | 91.44 cm = 0.9144 m |
| 1 mile | 1.609344 km = 1,609.34 m |
| 1 cm | 0.3937 in |
| 1 m | 3.28084 ft = 39.3701 in |
| 1 km | 0.621371 miles |
Feet and Inches to Centimeters: Height Conversion Chart
Heights from 4’10” to 6’6” in 1-inch increments. To convert any height, multiply the total number of inches by 2.54. For example, 5 feet 10 inches = 70 in × 2.54 = 177.8 cm.
| Height (ft / in) | Centimeters | Meters |
|---|---|---|
| 4’10” | 147.32 cm | 1.47 m |
| 4’11” | 149.86 cm | 1.50 m |
| 5’0” | 152.40 cm | 1.52 m |
| 5’1” | 154.94 cm | 1.55 m |
| 5’2” | 157.48 cm | 1.57 m |
| 5’3” | 160.02 cm | 1.60 m |
| 5’4” | 162.56 cm | 1.63 m |
| 5’5” | 165.10 cm | 1.65 m |
| 5’6” | 167.64 cm | 1.68 m |
| 5’7” | 170.18 cm | 1.70 m |
| 5’8” | 172.72 cm | 1.73 m |
| 5’9” | 175.26 cm | 1.75 m |
| 5’10” | 177.80 cm | 1.78 m |
| 5’11” | 180.34 cm | 1.80 m |
| 6’0” | 182.88 cm | 1.83 m |
| 6’1” | 185.42 cm | 1.85 m |
| 6’2” | 187.96 cm | 1.88 m |
| 6’3” | 190.50 cm | 1.91 m |
| 6’4” | 193.04 cm | 1.93 m |
| 6’5” | 195.58 cm | 1.96 m |
| 6’6” | 198.12 cm | 1.98 m |
Kilometers to Miles (and Miles to Kilometers)
Popular running and driving benchmarks — from a local 5K to a 100K ultramarathon. Formula: km × 0.621371 = miles; miles × 1.609344 = km.
Kilometers to Miles
| Kilometers | Miles | Note |
|---|---|---|
| 5 km | 3.107 mi | Parkrun / 5K race |
| 10 km | 6.214 mi | 10K race |
| 15 km | 9.321 mi | |
| 20 km | 12.427 mi | |
| 21.1 km | 13.110 mi | Half marathon |
| 25 km | 15.534 mi | |
| 30 km | 18.641 mi | |
| 42.2 km | 26.219 mi | Full marathon |
| 50 km | 31.069 mi | Ultramarathon |
| 100 km | 62.137 mi | Ultramarathon |
Miles to Kilometers
| Miles | Kilometers | Note |
|---|---|---|
| 1 mi | 1.609 km | |
| 3 mi | 4.828 km | |
| 5 mi | 8.047 km | |
| 10 mi | 16.093 km | |
| 13.1 mi | 21.082 km | Half marathon |
| 26.2 mi | 42.165 km | Full marathon |