Convert Kilometers to Nautical Miles – Length Converter
This tool converts a distance given in kilometres (kilometers) into international nautical miles. The international nautical mile is defined exactly as 1852 metres and is the standard used in maritime and aviation contexts.
Use this converter for chart reading, flight planning, navigation calculations, or general unit conversion. Results are presented as a direct mathematical conversion; follow the guidance below on rounding and regulatory compliance for operational use.
Interactive Converter
Convert between kilometer and nautical mile with precision rounding.
Quick reference table
| Kilometer | Nautical Mile |
|---|---|
| 1 km | 0.54 nmi |
| 5 km | 2.6998 nmi |
| 10 km | 5.3996 nmi |
| 25 km | 13.4989 nmi |
| 50 km | 26.9978 nmi |
| 100 km | 53.9957 nmi |
Methodology
Conversion is performed using the international nautical mile definition of exactly 1852 metres. One kilometre equals 1000 metres, therefore the exact ratio is 1000/1852 nautical miles per kilometre.
Displayed numeric results are produced from standard IEEE-754 double-precision arithmetic and then rounded for presentation. For formal or regulated workflows, follow the rounding, reporting, and documentation rules required by relevant authorities and standards organizations.
Worked examples
Example 1: 1 kilometre → 1 × (1000 ÷ 1852) = 0.5399568034557234 nautical miles. Rounded to three decimals: 0.540 nmi.
Example 2: 10 kilometres → 10 × (1000 ÷ 1852) ≈ 5.399568034557234 nautical miles. Rounded to two decimals for display: 5.40 nmi.
Example 3: 123.456 kilometres → 123.456 × (1000 ÷ 1852) ≈ 66.663 nmi when rounded to three decimal places.
Key takeaways
Use the exact ratio 1 km = 1000/1852 nmi (≈ 0.5399568034557234) for conversions.
Round results based on context and applicable regulations. For safety-critical applications, follow formal procedures and maintain instrument calibration records.
Further resources
External guidance
Expert Q&A
Which definition of the nautical mile does this converter use?
This converter uses the international nautical mile defined as exactly 1852 metres, which is the standard in aviation and maritime navigation.
How many decimal places should I use for operational navigation?
Decimal places depend on context. For chart-level distances, two or three decimals are typically sufficient. For precision navigation or instrument flight planning, follow the accuracy and rounding rules in your operational procedures and applicable regulations.
Are there alternative definitions of the nautical mile?
Historically other definitions existed, but the internationally accepted definition is 1852 metres. Use the international definition for modern navigation and regulatory compliance.
What are the accuracy limitations of the calculator?
The mathematical conversion uses exact unit definitions but numeric results are subject to floating-point rounding per IEEE-754. For legal, safety-critical, or certified measurements, refer to official instrument calibration records and standards and report values according to the required number of significant figures.
Can I convert back from nautical miles to kilometres?
Yes. Use the reciprocal factor: kilometres = nautical miles × 1.852. For convenience, use a two-way converter or perform the reciprocal operation as needed.
Sources & citations
- NIST Special Publication 811 - Guide for the Use of the International System of Units (SI) — https://www.nist.gov/pml/special-publication-811
- BIPM - Units and Definitions (SI Brochure) — https://www.bipm.org/en/measurement-units/
- ISO 80000 series — Quantities and units (space and time) — https://www.iso.org/standard/64949.html
- IEEE 754-2019 Standard for Floating-Point Arithmetic — https://standards.ieee.org/standard/754-2019.html
- OSHA - Occupational Safety and Health Administration — https://www.osha.gov/