Convert Rod to Span
Convert rods to spans instantly. 1 rod = 22 span — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Span 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.
Span
A span is an Imperial unit of length equal to 9 inches (228.6 mm). Historically, it represented the distance from the tip of an extended thumb to the tip of an extended little finger.
The span derives from this natural body-measurement and was standardised at 9 inches in English customary practice.
Spans are rare in modern commerce but appear in historical English literature, biblical translation studies, and reproduction crafts. Some construction and gardening still use 'span' informally.
Ancient body-measure origin; standardised in English customary practice at 9 inches; became exact via the 1959 International Yard and Pound Agreement.
Rod to Span conversion formula
The relationship between rods and spans:
To convert rods to spans, multiply the value in rods by 22. To reverse, multiply spans by 0.0454545455.
How to use this converter
Type a value into the calculator. The result in spans updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Span to Rod converter for the reverse direction.
Step-by-step: convert rods to spans
- Write down the value in rods (rd).
- Multiply that value by the factor 22.
- The product is the equivalent value in spans (span).
- To reverse, multiply the span value by 0.0454545455.
Worked examples
Example 1 — Convert 1 rd to span:
1 × 22 = 22 span
Example 2 — Convert 100 rd to span:
100 × 22 = 2200 span
Real-world example — Adult height conversion
A 1.8-rod-tall person measures a value in spans 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 × 22 = 39.6 span
Real-world example — Fabric purchase length
Two rods of fabric equals a value in spans essential for tailors and textile buyers sourcing material from international suppliers that quote in different units.
2 rd × 22 = 44 span
Real-world example — Maritime depth conversion
A 10-rod sounding depth converts cleanly into spans. Recreational divers and sailors translate between the two units whenever they read legacy charts against modern depth-sounder displays.
10 rd × 22 = 220 span
Rod to Span conversion table
Standard reference values for converting rods to spans:
| Rod [rd] | Span [span] |
|---|---|
| 0.01 | 0.22 |
| 0.1 | 2.2 |
| 1 | 22 |
| 2 | 44 |
| 3 | 66 |
| 4 | 88 |
| 5 | 110 |
| 10 | 220 |
| 20 | 440 |
| 30 | 660 |
| 40 | 880 |
| 50 | 1100 |
| 100 | 2200 |
| 500 | 11000 |
| 1000 | 22000 |
Frequently asked questions
How many spans is 1 rod?
How do I convert rods to spans?
How do I convert spans back to rods?
How many spans is 100 rods?
Popular length unit conversions
Convert Rod to other length units
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Metric / SI (4 units)
Imperial / US Customary (26 units)
Sources & references
Conversion factor (1 rd = 22 span) 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.