Speed limits in km/h, converted to mph
The 30, 50, 90 and 130 km/h signs translated into mph, a full chart in both directions, and why a limit that reads round in one unit is a decimal in the other.
By Akash Yadav Updated 30 October 2026
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Type a speed instead
A chart is for the numbers that appear on signs, and those are a short list. For a speedometer reading, a rental-car limit or anything in between, use the card — it is the same one as the full km/h to mph page, which also shows the exact factor and a worked example.
Type a number above to see the answer.
Or tap a number:
Open the full km/h to mph page →
Kilometres to miles
km/h signs in mph
These are the limits you meet on a km/h sign, converted to one decimal place. The mph figure is what a US or UK speedometer would show at that limit — which is not the same as a round number, and that is the point of the table: no round km/h limit converts to a round mph one.
| km/h | mph |
|---|---|
| 20 km/h | 12.4 mph |
| 30 km/h | 18.6 mph |
| 40 km/h | 24.9 mph |
| 50 km/h | 31.1 mph |
| 60 km/h | 37.3 mph |
| 70 km/h | 43.5 mph |
| 80 km/h | 49.7 mph |
| 90 km/h | 55.9 mph |
| 100 km/h | 62.1 mph |
| 110 km/h | 68.4 mph |
| 120 km/h | 74.6 mph |
| 130 km/h | 80.8 mph |
The two that catch people out: a 30 km/h zone is 18.6 mph, close enough to a US 20 mph limit to invite a fine, and 100 km/h is 62.1 mph, not 60. The error grows with the speed because the factor is fixed rather than additive: assuming 50 km/h is 30 mph is 1.1 mph out, and assuming 100 km/h is 60 mph is 2.1 mph out.
Miles to kilometres
mph signs in km/h
The other direction is what a km/h speedometer shows in a country that signs in mph. Same rows, converted the other way.
| mph | km/h |
|---|---|
| 20 mph | 32.2 km/h |
| 25 mph | 40.2 km/h |
| 30 mph | 48.3 km/h |
| 40 mph | 64.4 km/h |
| 50 mph | 80.5 km/h |
| 60 mph | 96.6 km/h |
| 70 mph | 112.7 km/h |
| 80 mph | 128.7 km/h |
A 70 mph motorway limit is 112.7 km/h, which is why a km/h speedometer reads just under 113 at the limit rather than a round 110. The mph to km/h converter takes any value; the km/h to m/s page is the one to use if the number is going into physics rather than onto a road.
The arithmetic
Why no round limit converts to a round number
One mile is exactly 1.609344 km, so 1 km/h is 0.621371 mph and 1 mph is 1.609344 km/h. Neither number is a fraction of small whole numbers, so multiplying a round limit by one of them gives a decimal — every time, in both directions. That is not rounding error; it is the exact answer, and the one-decimal column here is the rounded version of it.
For a mental check, multiply by 5 and divide by 8: 80 km/h becomes 400 ÷ 8 = 50, against the exact 49.7. Five-eighths is 0.625 against the true 0.621371, so the shortcut is never more than about 0.6% out — closer than a speedometer reads.
Before you rely on it
What this conversion does not cover
Speed limits are set in the unit the sign uses, and the sign is the law — a conversion tells you what the limit is worth on your own dial, never what a different limit would be. Limits also change by road type, time of day and weather, and rental cars often show only one unit, so the table is a reading aid rather than a substitute for the sign.
This page converts km/h and mph only. Knots to mph covers boat and aircraft speeds, and knots to km/h the same in metric.
Common questions
About these limits
What is 30 km/h in mph?
30 km/h is 18.6 mph.
What is 50 km/h in mph?
50 km/h is 31.1 mph — the commonest town limit on a km/h sign.
What is 70 km/h in mph?
70 km/h is 43.5 mph.
What is 80 km/h in mph?
80 km/h is 49.7 mph.
What is 100 km/h in mph?
100 km/h is 62.1 mph, not 60 — a mistake worth about 2 mph on a dial that reads in miles.
What is 120 km/h in mph?
120 km/h is 74.6 mph.
What is 130 km/h in mph?
130 km/h is 80.8 mph — the highest limit in the chart, and the one most often looked up.
What is 60 mph in km/h?
60 mph is 96.6 km/h, just under 97.
Is 100 km/h the same as 60 mph?
No. 60 mph is 96.6 km/h, and 100 km/h is 62.1 mph. They are close enough to feel the same and about 4 mph apart.
Why should I trust these numbers?
They are computed at build time from the same engine as the converters, whose factors are the defining standards listed on the methodology page — here, the international mile of exactly 1.609344 km. A row that disagreed with the converter would fail the build.
Use it
Converters in this guide
Every figure in this guide is computed at build time from the same conversion engine as the converters it links to, and the factors behind it are the defining standards listed on the methodology page. Nothing here is typed by hand from a template.
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