Miles to Kilometers Converter

The statute (land) mile and the kilometre are the two distance units used for road distances worldwide. One statute mile = exactly 1.609344 kilometres, fixed by the international yard-and-pound agreement of 1 July 1959 among the United States, United Kingdom, Canada, Australia, New Zealand and South Africa. The agreement also fixed the yard at 0.9144 m exactly (and therefore the foot at 0.3048 m exactly), which means a mile of 1,760 yards is 1,760 × 0.9144 = 1,609.344 m = 1.609344 km, exact to the last digit.

This converter works in both directions: type a value into either field and the other updates. It includes race-distance presets (5K, 10K, half marathon, marathon, 100 km ultra) and bonus read-outs in metres, feet and yards so a single calculation handles most distance-conversion needs. The conversion is exact, no rounding error accumulates, so the output is suitable for navigation, training plans, fuel-economy calculations, sporting events and any professional or commercial use.

Important: This converter uses the statute mile (1,609.344 m), NOT the nautical mile (1,852 m exactly, used at sea and in aviation). Conflating the two is one of the most common mistakes in distance conversion.

How to Use

1. Miles (mi), enter any non-negative number of statute miles. Decimal input is fine (e.g. 0.5 for half a mile).
2. Kilometres (km), enter any non-negative number of kilometres. The other field updates automatically based on the exact factor 1 mi = 1.609344 km.
3. The result block shows the conversion in km and metres, plus the equivalent in feet and yards (since a US runner might want to know how many feet of elevation gain a 5K route involves, or a UK hiker might want yards for an OS map grid).
4. Use the presets for race distances, 5K, 10K, half marathon (21.0975 km / 13.1 mi), marathon (42.1648 km / 26.2 mi) and 100 km ultra. Click to populate both fields.

The Formulae

The conversion rests on one exact definition:

1 international yard = 0.9144 m          (1 July 1959 agreement, exact)
1 international foot = 0.3048 m          (1 yd / 3, exact)
1 statute mile       = 1,760 yards       (UK Weights and Measures Act 1985)
                    = 1,760 × 0.9144 m
                    = 1,609.344 m        (exact)
                    = 1.609344 km        (exact)

To go from miles to kilometres:

km = mi × 1.609344

To go from kilometres to miles:

mi = km / 1.609344
       = km × 0.6213711922373339…

The reverse factor is a repeating decimal, so for high-precision work always divide by 1.609344 rather than multiply by 0.6213711922 (the latter rounds the seventh decimal place).

For the race distances used as presets:

(Note: the marathon is officially 42.195 km by IAAF rule from 1921; 26.2 mi is a rounded form. The displayed conversion is 26.2 mi ≈ 42.1648 km.)

Worked Examples

Example 1, 1 statute mile:

• km = 1 × 1.609344 = 1.609344 km (exact)
• m = 1,609.344 m
• ft = 5,280 ft
• yd = 1,760 yd

Example 2, 5 miles:

• km = 5 × 1.609344 = 8.04672 km (exact)
• m = 8,046.72 m
• ft = 26,400 ft

Example 3, Marathon distance (26.2 mi):

• km = 26.2 × 1.609344 = 42.1648128 km
• (officially the marathon is 42.195 km; 26.2 mi is a common rounded equivalent)

Example 4, 100 kilometres (century ride / ultra run):

• mi = 100 / 1.609344 = 62.1371192237… mi ≈ 62.13712 mi
• m = 100,000 m
• ft = 328,083.99 ft

Example 5, Half marathon (21.0975 km, IAAF standard):

• mi = 21.0975 / 1.609344 = 13.1094… mi ≈ 13.1 mi
• m = 21,097.5 m

Example 6, 1 km:

• mi = 1 / 1.609344 = 0.6213711922… mi
• (repeating decimal; never round to fewer than 6 decimal places for precision work)

Example 7, 60 miles at 60 mph = 1 hour:

• km = 60 × 1.609344 = 96.56064 km in 1 hour
• (so 60 mph ≈ 96.56064 km/h, exactly)

Example 8, 1,000 miles (a common cross-country driving distance):

• km = 1,000 × 1.609344 = 1,609.344 km

Example 9, 0.5 mile (half-mile track lap or short walk):

• km = 0.5 × 1.609344 = 0.804672 km
• m = 804.672 m

Example 10, Speed conversion check (60 mph → km/h):

• 60 mph = 60 mi/h = 60 × 1.609344 km/h = 96.56064 km/h
• (so the speedometer "100 km/h" mark ≈ 62.137 mph, "120 km/h" ≈ 74.565 mph)

Where It Shows Up

• Road trip planning and navigation, drivers crossing the US/Canada or US/Mexico border need to interpret distances in both miles and kilometres; this converter is the canonical reference.
• Vehicle speedometers, most Canadian, Mexican, European and Asian cars have km/h primary markings with mph secondary (or vice versa for US-spec cars exported to Europe); converting between the two is essential.
• Running and cycling training plans, most international training plans (Garmin, Strava, NRC, etc.) display in the unit the user selects, but race results and comparison data often come in mixed units; this converter handles both.
• Marathon and half-marathon training, official distances are in km (42.195 km marathon, 21.0975 km half marathon) but American runners often think in miles ("26.2", "13.1"). This converter is the bridge.
• Fuel economy calculations, US "miles per gallon" vs international "litres per 100 km" require the distance conversion as one of the two intermediate steps.
• Aviation and maritime navigation, note the warning: aviation uses the nautical mile (1.852 km), not the statute mile. This converter is NOT for nautical miles; if you're converting flight distances, use a nautical mile converter instead.
• Mapping and surveying, GIS systems and Ordnance Survey grid references can be in either unit; the converter is the standard reference for converting between imperial and metric spatial data.
• Astronomy (loosely), the "light-year" is approximately 9.46 × 10¹² km, which is 5.88 × 10¹² statute miles; this converter is one step in the chain (though light-years and parsecs are the more common units at interstellar scales).

Common Mistakes

1. Confusing statute miles with nautical miles, the nautical mile is 1,852 m (1.852 km), not 1.609344 km. Using the wrong unit introduces a 15% error in any distance conversion at sea or in the air. This converter uses the statute mile.
2. Using 1.6 instead of 1.609344, the rounded factor 1.6 km/mi is fine for mental math but introduces ~0.6% error, which matters over long distances (a 1,000-mile trip calculated with 1.6 is 9.344 km off). This converter uses the exact 1.609344.
3. Multiplying by 0.6214 instead of dividing by 1.609344, when going km → mi, dividing by 1.609344 is exact; multiplying by 0.6214 truncates the seventh decimal place. For most uses this is fine, but for surveying or precision engineering it accumulates.
4. Treating "mile" as ambiguous, there are at least three definitions: statute mile (1.609344 km, used on roads), nautical mile (1.852 km, used at sea/air), and the historical Roman mile (~1.48 km). This converter uses statute miles only.
5. Confusing "kilometre" with other metric units, the kilometre is 1,000 metres; the centimetre, metre, decametre and other prefixes are different units entirely. This converter does kilometres only.
6. Rounding marathon distance to 26 mi exactly, the marathon is 26.2188 mi (42.1648 km), not 26.0 mi. A "26-mile marathon" doesn't exist as an official distance; the 26.2 figure (used as shorthand) is rounded from 26.2188.
7. Using the converter on the wrong input unit, if you have 5 kilometres and accidentally type "5" into the miles field, you'll get 8.04672 km (= 5 mi). The reverse conversion (km field as input) gives the right answer.
8. Forgetting that some countries use both, the UK officially uses miles for road signs and pints for beer, but kilometres for fuel economy and metres for height; the US uses miles and feet for distance/height, gallons for fuel. Mixed-unit conversion is normal in both countries.

Frequently Asked Questions

How many kilometres are in a mile? One statute mile = exactly 1.609344 kilometres, by the international yard-and-pound agreement of 1 July 1959 (which fixed the yard at 0.9144 m exactly, making 1 mile of 1,760 yards equal to 1,760 × 0.9144 = 1,609.344 m = 1.609344 km). This is the only definition recognised for road distances in the US, UK, Canada, Australia, NZ and South Africa.

How many miles are in a kilometre? One kilometre = 1 / 1.609344 = 0.6213711922373339… statute miles (repeating decimal). For most uses 0.6214 mi is sufficient, but the exact value is the inverse of 1.609344. Never multiply by a rounded factor for precision work; always divide by 1.609344.

What's the difference between a statute mile and a nautical mile? The statute mile (1.609344 km) is the road mile used in the US, UK and a handful of other countries. The nautical mile (1.852 km exactly, by the 1929 International Hydrographic Conference) is the sea/air mile used worldwide for marine and aviation navigation. They differ by 15% (the nautical mile is longer). This converter uses the statute mile; do not use it for nautical distances.

Is 1.609344 exact or rounded? Exact, to the full precision of the 1959 international agreement. The yard is fixed at 0.9144 m exactly; 1 mile = 1,760 yards = 1,609.344 m exactly; 1 mile = 1.609344 km exactly. There is no rounding in the definition itself.

How long is a marathon in miles? A marathon is officially 42.195 km by IAAF rule (set in 1921, formalised by the IOC in 1924 for the Paris Olympics). In miles this is 42.195 / 1.609344 = 26.21875 mi, which is rounded to "26.2 miles" for shorthand. This converter uses 26.2 mi = 42.1648 km as the marathon preset.

How long is a 5K in miles? 5 kilometres = 5 / 1.609344 = 3.10686 mi ≈ 3.107 mi. A 5K race is therefore about 3.1 miles.

What's the conversion for 60 mph to km/h? 60 mph = 60 × 1.609344 = 96.56064 km/h. This is exact. The reverse: 100 km/h = 100 / 1.609344 = 62.137 mph. These are the canonical speedometer cross-reference values.

Why do some countries use miles and others kilometres? Most countries use the metric system (kilometres, metres) for road distances. The United States, United Kingdom, Myanmar and Liberia still use imperial units (miles, yards, feet) for road signs. Both the US and UK officially use metric for science, medicine and trade; the road-mile usage is a cultural/practical retention rather than a rejection of metric. Most vehicles sold in mixed-unit countries display both.

Can I use this converter for nautical distances? No, this converter uses the statute mile. For nautical distances, use a dedicated nautical mile converter or apply the factor 1 nautical mile = 1.852 km = 1.150779448 statute miles.

How accurate is this converter? Mathematically exact at the 1.609344 km/mi level. Display rounding is to 5 decimal places for kilometres and 5 for miles, which gives precision finer than any practical road-distance measurement (a 1-millimetre error requires a distance of ~1.6 km before it appears). All definitions are from the UK statute and the international agreement.

Is this calculator suitable for professional or commercial use? yes, the Miles to Kilometers Converter, 1 mi = 1.609344 km Exact provides mathematically correct results that are suitable for professional, commercial, and educational use. For high-stakes applications (legal land descriptions, aviation, marine navigation, surveying), verify results with a domain expert and use the unit appropriate to the context. The formulas used are well-established and validated against reference standards from NIST and the BIPM.

For the Miles to Kilometers Converter, 1 mi = 1.609344 km Exact, How often are the underlying formulas updated? For the Miles to Kilometers Converter, 1 mi = 1.609344 km Exact, the Miles to Kilometers Converter, 1 mi = 1.609344 km Exact formulas are based on established scientific, mathematical, or industry-standard references and rarely require updates. When standards change (e.g., redefinitions of SI base units), this calculator is updated to reflect the current authoritative source. For the Miles to Kilometers Converter, 1 mi = 1.609344 km Exact, For the Miles to Kilometers Converter, 1 mi = 1.609344 km Exact, Each calculator's references section lists the specific sources used.

References

1. International yard-and-pound agreement of 1 July 1959 among the US, UK, Canada, Australia, New Zealand and South Africa, fixed 1 yard = 0.9144 m exactly. Federal Register, US National Archives.
2. UK Weights and Measures Act 1985 (c. 72), Schedule 1, confirms the statute mile as 1,760 yards. The Stationery Office, London.
3. For the Miles to Kilometers Converter, 1 mi = 1.609344 km Exact, NIST Special Publication 811 (2008), Appendix B.6, Recommended conversion factors for length, including the exact 1 mi = 1.609344 km factor. For the Miles to Kilometers Converter, 1 mi = 1.609344 km Exact, National Institute of Standards and Technology.
4. For the Miles to Kilometers Converter, 1 mi = 1.609344 km Exact, BIPM SI Brochure (9th edition, 2019), §2.3.1, defines the metre via the speed of light (since 1983). For the Miles to Kilometers Converter, 1 mi = 1.609344 km Exact, Bureau International des Poids et Mesures, Sèvres.
5. International Hydrographic Conference (1929), defined the nautical mile as 1,852 m exactly. Monaco.
6. IAAF (now World Athletics) Competition Rules 2024, Rule 260.14, marathon distance of 42.195 km (since 1921, formalised at the 1924 Paris Olympics).
7. Taylor, B. N. and Thompson, A. (eds.), NIST Special Publication 811 (2008 edition), the canonical US reference for unit conversions.

Also try these free tools:

• Yards to Feet Converter, for shorter imperial/metric length conversions
• Kilograms to Pounds Converter, mass conversions using the same 1959 agreement
• Speed Converter, if you need to convert speeds (mph ↔ km/h ↔ m/s ↔ knots)
• Pace Calculator, for runners converting min/mile to min/km