- How do you convert kph to mph?
- Divide by 1.609344. That's the exact number of kilometers in a mile, fixed in 1959 when the US, UK, and other Commonwealth countries agreed a yard is exactly 0.9144 m (a mile is 1,760 yards, so 1,609.344 m). The hour is the same on both sides, so the distance factor is the whole conversion: 100 km/h ÷ 1.609344 = 62.14 mph. Multiplying by 0.621371 gives the same answer.
- Is there a quick way to do it in my head?
- Multiply by 5 and divide by 8. 80 km/h × 5 ÷ 8 = 50 mph; the exact answer is 49.71, so the shortcut reads about half a percent high. The rougher version is 'multiply by 6 and drop a zero': 120 km/h → 72 mph, against an exact 74.56. That one reads about 3.5% low — close enough for a glance at a sign, too loose for a spec sheet.
- What are common speed limits in mph?
- 50 km/h, the usual town limit across much of Europe, is 31.07 mph. 80 km/h is 49.71 mph and 90 km/h is 55.92 mph, typical for rural roads. 100 km/h, the standard highway limit in much of Canada, is 62.14 mph. 110 km/h is 68.35 mph, 120 km/h is 74.56 mph, and 130 km/h — the motorway limit in France and the advisory speed on German autobahns without a posted limit — is 80.78 mph. Limits change by country, road, and weather, so trust the sign, not a table.
- My rental car shows km/h. How do I avoid speeding?
- Match the sign to the speedometer, not to your habits. If the car shows km/h and the signs are in km/h, you don't need to convert at all — keep the needle under the number on the sign. The trouble starts when the units differ: a US car driven into Canada shows mph big and km/h small, and a 100 sign means 62 mph, not 100. Type the posted limit here once and you'll have the mph number to hold. Most cars sold in the US and UK show both scales; the smaller inner ring is the other unit.
- How do I convert km/h to meters per second?
- Divide by 3.6. A kilometer is 1,000 m and an hour is 3,600 s, so 1 km/h is 1,000 ÷ 3,600 = 0.2778 m/s. 36 km/h is exactly 10 m/s, and 90 km/h is exactly 25 m/s. The result card shows m/s under every conversion because physics problems, sprint times, and some wind reports use it.
- What about knots?
- A knot is one nautical mile per hour, and a nautical mile is exactly 1.852 km, so knots = km/h ÷ 1.852. 100 km/h is 54 knots. Boats, planes, and marine weather forecasts use knots. This converter gives statute (land) miles per hour — the unit on US and UK road signs — so don't read its mph figure as knots; it would be about 15% high.
- How strong is a storm with winds in km/h?
- Weather services outside the US often report wind in km/h. A hurricane (or typhoon) starts at 119 km/h sustained, which is 74 mph — the bottom of Category 1 on the Saffir-Simpson scale. Category 3, the start of 'major', is 178 km/h or 111 mph, and Category 5 is 252 km/h or 157 mph. If a forecast gives gusts in km/h, type them in the same way.
- Why do the US and UK still use mph?
- Replacing every road sign is expensive and drivers resist it. The UK went metric for most things but kept miles and mph on roads. The US never switched road measurement. Canada, Australia, and Ireland all moved their roads to km/h in the 1970s and 2000s. So a car, map, or sign from almost anywhere else will hand you km/h, and a US or UK one will hand you mph.
- Is what I type saved or sent anywhere?
- No. The conversion runs in your browser. Nothing is sent to a server or stored, and closing the tab clears it.
