Value to convert
One number, every unit
Enter a value once and all nine units update together. Converting in two steps — metres to feet, then feet to inches — is where rounding usually creeps in; here everything is derived from the same metre value.
The inch has been exact since 1959
The international yard and pound agreement fixed the inch at exactly 25.4 mm, the foot at 0.3048 m and the mile at 1609.344 m. Before that, the US and imperial inches differed slightly. A nautical mile is a separate thing again: exactly 1852 m, chosen to be about one minute of latitude.
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Frequently asked questions
Q. Why is a nautical mile not the same as a mile?
A nautical mile is tied to the Earth, not to a foot. It is one minute of arc along a meridian, standardised as exactly 1852 m — about 15% longer than a statute mile.
Q. Is the US inch the same as the UK inch?
Yes, since 1959. The US survey foot lingered for land surveying and was slightly longer, but it was officially retired at the end of 2022.
Q. How precise are the results?
Eight significant figures. Very large or very small values switch to scientific notation instead of padding out zeros.