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Convert Meters to Chains - Length Converter

This tool converts a length given in metres to chains using the conventional survey chain (Gunter's chain). By international agreement of base units, 1 chain is 66 feet, which equals 20.1168 metres exactly when a foot is taken as 0.3048 m.

The converter applies the fixed mathematical relationship between the two units. The numeric result is driven by the input value and the chosen display precision; measurement uncertainty depends on the source measurement, not the arithmetic conversion.

Guidance below explains the calculation, recommended rounding practices, and references to standards for unit use and uncertainty reporting.

Updated Nov 13, 2025

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Methodology

Definition used: 1 chain = 66 feet = 20.1168 metres. This follows the exact definition of the foot (0.3048 m) and the historical definition of the Gunter chain. The conversion is therefore an exact arithmetic mapping between units.

Calculation approach: convert metres to chains by dividing the metre value by 20.1168 (chains = metres / 20.1168). For presentation the tool supports configurable rounding; choose precision consistent with measurement uncertainty and application requirements.

Accuracy and reporting: arithmetic conversion is exact to the precision of the computer arithmetic, but measured lengths carry uncertainty. Follow NIST guidelines on unit use and uncertainty reporting and ISO guidance on quantities and units when documenting results.

Numerical issues: binary floating-point arithmetic follows common IEEE practices; for high-precision or bulk conversions use a numerical mode or library that conforms to IEEE 754 recommendations or a decimal arithmetic library if exact decimal rounding is required.

Worked examples

Example 1: 1 metre → 1 ÷ 20.1168 = 0.049709695 chains (approx. 0.04971 chains when rounded to 5 significant digits).

Example 2: 20.1168 metres → 20.1168 ÷ 20.1168 = 1 chain.

Example 3: 100 metres → 100 ÷ 20.1168 = 4.9709695 chains (approx. 4.971 chains when rounded to 3 decimal places).

Key takeaways

Use chains = metres ÷ 20.1168 for conversions between metres and Gunter's chains. The arithmetic mapping is exact given the unit definitions.

Always consider and report measurement uncertainty and choose display precision appropriate to your measurement's accuracy. Refer to the cited standards for guidance on units and uncertainty reporting.

Further resources

Expert Q&A

Which chain definition does this converter use?

This converter uses the Gunter (survey) chain: 1 chain = 66 feet = 20.1168 metres, consistent with the exact definition of the foot as 0.3048 m.

What is the exact formula to convert metres to chains?

chains = metres ÷ 20.1168. You may also compute chains = metres × 0.049709695 (approx.).

How accurate is the conversion?

The arithmetic conversion uses the exact relationship between the defined units; any inaccuracy arises from the precision of the input measurement and floating-point rounding. For reporting, follow NIST and ISO guidance on uncertainty evaluation and state the measurement uncertainty separately from the converted value.

How should I choose rounding or displayed decimals?

Choose rounding that reflects the underlying measurement uncertainty and application requirements (surveying, mapping, engineering). Do not imply greater precision than the original measurement. See NIST guidance on expressing uncertainty for best practice.

Are there any regulatory or safety considerations?

Unit conversion itself is a mathematical operation. For regulated work (e.g., legal land descriptions, construction, safety-critical measurements), follow applicable national or sector regulations and standards and keep traceable records of original measurements, calibration certificates, and uncertainty estimates.

Can I convert negative values or very large numbers?

Yes. Negative values convert normally (they represent direction or displacement). For extremely large or small magnitudes, be mindful of floating-point limits and use arbitrary-precision or decimal libraries if required for exact rounding or legal documentation.

Sources & citations