Miles to km Converter
Convert miles to kilometers and kilometers back to miles, plus mph to km/h and running pace (min/mi to min/km). Type a value into either field of a pair and the converter updates the rest instantly.
Convert Miles to Kilometers — and Kilometers Back to Miles
Miles to km Formula
Where:
- \(\text{mi}\) — distance or speed in miles (or miles per hour)
- \(\text{km}\) — the same distance or speed in kilometers (or kilometers per hour)
- \(1.609344\) — the exact number of kilometers in one mile, from the definition 1 mi = 5,280 ft and 1 ft = 0.3048 m (international yard and pound agreement, 1959)
Because a mile is longer than a kilometer, mile values are always smaller than the matching kilometer values. Speed converts with the same factor as distance, while pace (time per unit distance) works the other way around: more kilometers per mile means fewer minutes per kilometer, so you divide by 1.609344.
Miles to km – Calculation Example
Example: you plan a 5-mile run and want the distance, your driving speed of 60 mph, and your running pace of 8 minutes per mile in metric units.
\[ \text{Distance: } 5 \times 1.609344 = 8.04672\ \text{km} \\ \text{Speed: } 60 \times 1.609344 = 96.56064\ \text{km/h} \\ \text{Pace: } 8 \div 1.609344 = 4.97097\ \text{min/km} \approx 4{:}58\ \text{per km} \]
Result: 5 miles = 8.04672 km (about 8.05 km); 60 mph = 96.56064 km/h (about 97 km/h); 8:00 per mile = 4:58 per kilometer (4.97097 min/km).
How to use the calculator
- Type a distance into Miles (mi) to see it in Kilometers (km), or type into the Kilometers (km) field to convert back — the converter follows whichever field you edited last.
- Enter a speed in Miles per hour (mph) or Kilometers per hour (km/h) in the Speed Converter pair.
- Enter your running pace as decimal minutes, e.g. 8.5 for 8:30, in Pace per mile (min/mi) or Pace per kilometer (min/km).
- Read the results: distance in miles and kilometers, speed in km/h and mph, and each pace shown both as decimal minutes and in m:ss form.
- Check the detail block for the exact arithmetic with your values, plus a 1–100 conversion table in each direction and a list of common race distances.
Each pair works independently. Leave a pair blank if you don't need it — blanking both fields of a pair simply skips that conversion, and negative values are rejected with an error message.
Miles, kilometers, and why the distinction matters
The mile is an imperial and US customary unit of length, defined since 1959 as exactly 5,280 international feet, which works out to 1.609344 km. The kilometer is the everyday metric distance unit — 1,000 meters. Only a handful of countries, including the United States and the United Kingdom, still use miles for road distances, so travelers, runners, and drivers constantly need to convert between the two.
A useful mental anchor: one mile is about 1.6 kilometers, so 10 miles is roughly 16 km. Going the other way, one kilometer is about 0.6214 miles, so a half marathon (21.0975 km) is a little over 13.1 miles. For quick estimates, multiply miles by 1.6 or kilometers by 0.6; for anything exact — race results, speed limits, engineering data — use the precise factor 1.609344.
Speed and pace are just distance conversions applied to time. A speed limit of 65 mph equals about 104.6 km/h, which matters when renting a car abroad: a sign reading 100 km/h is roughly 62 mph, not 100 mph. Pace, on the other hand, inverts: an 8:00-per-mile runner runs 10K in about 49:42 because 8 min/mi divides down to 4:58 per km. Runners between countries constantly translate paces this way to compare training plans and race splits.
Notes, assumptions and practical tips
- The conversion factor is exact: 1 mi = 1.609344 km. Any rounding error comes only from rounding the displayed result, not the formula.
- The calculator distinguishes the international mile used everywhere today. The older US survey mile (1.6093472 km) differs in the sixth decimal place and is irrelevant for everyday use.
- Nautical miles are a different unit entirely (1,852 m exactly) and are not handled by this factor.
- Pace fields use decimal minutes, not minutes:seconds. Enter 8.5 for 8:30 per mile; the results show the m:ss equivalent for you.
- Values must be non-negative; distances, speeds, and paces below zero are physically meaningless and trigger an error.
- Race distances in the results table use official metric definitions where they exist: a marathon is exactly 42.195 km (26.21875 mi) and a half marathon 21.0975 km (13.109375 mi).
- For fuel economy, miles per gallon does not convert with a simple factor — use the dedicated MPG to L/100km converter, since gallons and liters introduce a volume element.
If you work with other imperial–metric conversions, you may also find the kg to lbs converter, the cm to inches converter, and the feet and inches calculator useful.
Frequently Asked Questions
How do I convert miles to kilometers without a calculator?
Multiply miles by 1.609344, or use the quick mental rule of multiplying by 1.6. For example, 7 mi ≈ 7 × 1.6 = 11.2 km (exact: \(7 \times 1.609344 = 11.265408\) km). Going the other way, multiply kilometers by 0.6214, or roughly 0.6. The 1.6 shortcut is accurate to about half a percent, which is fine for estimates but not for race results or engineering work.
Which is longer, a mile or a kilometer?
A mile is longer: 1 mi = 1.609344 km, so a mile is about 1.6 kilometers, while a kilometer is only about 0.6214 miles (a bit less than two-thirds of a mile). This is why the same distance always shows a bigger number in kilometers than in miles — a 10-mile run is 16.09 km, and 10 km is only about 6.2 miles.
Why do I divide for pace but multiply for speed?
Speed is distance per hour, so the length factor applies directly: \(\text{km/h} = \text{mph} \times 1.609344\). Pace is time per distance, so it inverts: each kilometer takes less time than each mile, so \(\text{min/km} = \text{min/mi} \div 1.609344\). A common mistake is multiplying pace by 1.609344 — that makes an 8:00/mi runner look slower (12:52/km) instead of the correct 4:58/km.
How do I convert a pace written as minutes and seconds into decimal minutes?
Divide the seconds by 60 and add them to the minutes. For 8:30 per mile: \(8 + 30/60 = 8.5\) minutes. For 7:15 per km: \(7 + 15/60 = 7.25\) minutes. The calculator's pace fields expect this decimal form, then display the result back in m:ss. To go the other way, multiply the fractional part by 60: 4.97 min/km is 4 minutes plus \(0.97 \times 60 \approx 58\) seconds, i.e. 4:58.
Can I just use 1.6 or 0.62 instead of 1.609344?
For everyday estimates, yes — the error is under 0.6%, so a 100-mile trip is within about a mile when approximated. But for anything exact, use the full factor: 1.609344 km per mile is an exact definition (1 mile = 5,280 ft, 1 ft = 0.3048 m), not a measurement. Over long distances the gap accumulates — 100 km is 62.137 mi exactly but 62 mi with the shortcut.
Does the same factor convert mph to km/h and back?
Yes. Speed is just distance over time, and the hour doesn't change, so speeds convert with the same exact factor as distances: \(\text{km/h} = \text{mph} \times 1.609344\) and \(\text{mph} = \text{km/h} \div 1.609344\). So 70 mph is about 112.7 km/h, and a 110 km/h speed limit abroad is roughly 68 mph. This matters for drivers: confusing 100 km/h with 100 mph would nearly double your actual speed.
Does this converter work for nautical miles or US survey miles?
No. This calculator uses the international statute mile (1.609344 km) used for roads and running worldwide. A nautical mile is a completely different unit of exactly 1,852 m (about 1.1508 statute miles) used in aviation and marine navigation. The obsolete US survey mile (1.6093472 km) differs only in the sixth decimal place, so it is irrelevant for everyday conversions but worth knowing if you work with old US land survey data.