Convert Rod to Chain
Convert rods to chains instantly. 1 rod = 0.25 chain — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Chain to Rod converter for the reverse conversion.
Units explained
Rod
A rod is an Imperial unit of length equal to 16.5 feet (about 5.03 m). It is also called a perch or pole. Used historically in English and American land surveying.
The rod derives from medieval English land-surveying practice. Standardised at 16.5 feet (= 25 links of a surveyor's chain = 1/4 chain) by Edmund Gunter in 1620.
Rods are the standard unit in legacy US public-land-survey records, where lot dimensions are typically expressed in rods and chains. Modern surveyors generally use feet or meters but legacy deeds remain in rods.
Defined by Edmund Gunter in 1620 as 16.5 feet via the chain-based survey system; became exact via the 1959 International Yard and Pound Agreement.
Chain
A chain is an Imperial unit of length equal to 66 feet (20.1168 m), or exactly 4 rods or 100 links. It is the central unit in the Gunter chain-based land-survey system.
Defined by Edmund Gunter in 1620 specifically to make land-area arithmetic easy: 10 square chains = 1 acre exactly. The 66-foot length and 100-link subdivision were chosen so chain measurements could be added decimally.
Chains are the fundamental unit of legacy US public land surveys (the entire US township-and-range system uses chains). Modern survey work generally uses meters or feet, but legacy deeds remain in chains.
Invented by Edmund Gunter in 1620; standardised throughout English and American land survey; became exact via the 1959 International Yard and Pound Agreement.
Rod to Chain conversion formula
The relationship between rods and chains:
To convert rods to chains, multiply the value in rods by 0.25. To reverse, multiply chains by 4.
How to use this converter
Type a value into the calculator. The result in chains updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Chain to Rod converter for the reverse direction.
Step-by-step: convert rods to chains
- Write down the value in rods (rd).
- Multiply that value by the factor 0.25.
- The product is the equivalent value in chains (ch).
- To reverse, multiply the chain value by 4.
Worked examples
Example 1 — Convert 1 rd to ch:
1 × 0.25 = 0.25 ch
Example 2 — Convert 100 rd to ch:
100 × 0.25 = 25 ch
Real-world example — Adult height conversion
A 1.8-rod-tall person measures a value in chains that converts the height to the unit favoured by American forms, schools, or driver's licences. This is daily routine for anyone living between metric and imperial systems.
1.8 rd × 0.25 = 0.45 ch
Real-world example — Fabric purchase length
Two rods of fabric equals a value in chains essential for tailors and textile buyers sourcing material from international suppliers that quote in different units.
2 rd × 0.25 = 0.5 ch
Real-world example — Maritime depth conversion
A 10-rod sounding depth converts cleanly into chains. Recreational divers and sailors translate between the two units whenever they read legacy charts against modern depth-sounder displays.
10 rd × 0.25 = 2.5 ch
Rod to Chain conversion table
Standard reference values for converting rods to chains:
| Rod [rd] | Chain [ch] |
|---|---|
| 0.01 | 0.0025 |
| 0.1 | 0.025 |
| 1 | 0.25 |
| 2 | 0.5 |
| 3 | 0.75 |
| 4 | 1 |
| 5 | 1.25 |
| 10 | 2.5 |
| 20 | 5 |
| 30 | 7.5 |
| 40 | 10 |
| 50 | 12.5 |
| 100 | 25 |
| 500 | 125 |
| 1000 | 250 |
Frequently asked questions
How many chains is 1 rod?
How do I convert rods to chains?
How do I convert chains back to rods?
How many chains is 100 rods?
Popular length unit conversions
Convert Rod to other length units
Show all Rod conversions
Metric / SI (4 units)
Imperial / US Customary (26 units)
Sources & references
Conversion factor (1 rd = 0.25 ch) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.