Miles to Nautical Miles
Convert miles (mi) to nautical miles (nmi). Both measure distance and dimension, and the conversion comes up in construction, navigation, sports work.
The Formula
``
nautical miles = miles × 0.868976241901
miles = nautical miles × 1.15077944802
`
One mile is 0.868976 nautical miles, and one nautical mile is 1.1508 miles.
Conversion Table
| Miles | Nautical Miles |
|---|---|
| 1 mi | 0.868976 nmi |
| 2 mi | 1.738 nmi |
| 5 mi | 4.3449 nmi |
| 10 mi | 8.6898 nmi |
| 25 mi | 21.7244 nmi |
| 50 mi | 43.4488 nmi |
| 100 mi | 86.8976 nmi |
| 500 mi | 434.4881 nmi |
| 1,000 mi | 868.9762 nmi |
The Other Direction
| Nautical Miles | Miles |
|---|---|
| 1 nmi | 1.1508 mi |
| 2 nmi | 2.3016 mi |
| 5 nmi | 5.7539 mi |
| 10 nmi | 11.5078 mi |
| 25 nmi | 28.7695 mi |
| 50 nmi | 57.539 mi |
| 100 nmi | 115.0779 mi |
| 500 nmi | 575.3897 mi |
| 1,000 nmi | 1,150.78 mi |
What Each Unit Is
Miles (mi) — exactly 1,609.344 metres, by the 1959 international yard and pound agreement. The Roman mille passus — a thousand paces — later fixed by English statute at 5,280 feet.
Nautical Miles (nmi) — exactly 1,852 metres. One minute of latitude along a meridian, which is why it is the unit of sea and air navigation.
A Sense of Scale
A brisk walk covers a mile in 15 minutes- A marathon is 26.2 miles
- US speed limits are in mph
- One knot is one nautical mile per hour
- A nautical mile is about 15% longer than a statute mile
Doing It in Your Head
Multiply by 6, then divide by 7. That is off by 1.36% — close enough to judge a
distance, a weight or a price, and not close enough to sign off on a drawing.
Exact Mental shortcut 8.6898 nmi 8.5714 nmi 86.8976 nmi 85.7143 nmi
Precision
The factor 0.868976241901 is rounded. For engineering work carry more digits than the table above, and round only at the end — rounding at each step compounds.
Watch Out For
- A nautical mile is not a statute mile. Mixing them up understates a distance by roughly 15%.
In Code
`javascript
const mileToNauticalMile = (value) => value * 0.868976241901;
``
Where This Conversion Comes Up
- Construction
- Navigation
- Sports
- Sewing
- Mapping
How Many Decimals Do You Need?
Rounding the factor costs accuracy, and how much depends on the factor. Converting 137 mi with the factor truncated at each decimal place:
| Decimals kept | Factor | 137 mi becomes | Error |
|---|---|---|---|
| 0 | 1 | 137 | 15.0779% |
| 1 | 0.9 | 123.3 | 3.5702% |
| 2 | 0.87 | 119.19 | 0.1178% |
| 3 | 0.869 | 119.053 | 0.0027% |
| 4 | 0.869 | 119.053 | 0.0027% |
The right number of significant figures is set by your input, not by the converter. If you measured miles to three significant figures, the answer in nautical miles is only good to three — writing more digits claims precision the measurement never had.