Convert Rood to Square Mile
Convert roods to square miles instantly. 1 rood = 0.000390625 square mile — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Square Mile to Rood converter for the reverse conversion.
Units explained
Rood
A rood is an imperial unit of area equal to approximately 1011.71 m², or 1/4 of an acre. It was historically used in England and parts of the British Empire.
Defined as one-quarter of an acre; historically used in medieval English farming as the area one ox could plow in a day. The word relates to 'rod' as a measure of length used in plot dimensions.
Roods appear in historical English farming records, parish records, and old property deeds. The unit is functionally obsolete today.
Medieval English farming origin; standardized via the 1959 International Yard and Pound Agreement.
Square Mile
A square mile is an imperial unit of area equal to exactly 2,589,988.110336 m². It is used for measuring large land areas in the United States and the United Kingdom.
Derived by squaring the statute mile (5,280 feet). The mile was standardized via the 1959 International Yard and Pound Agreement.
Square miles are used for US and UK regional geography (county areas, lake sizes, large parks), national statistics, and military range descriptions. 1 mi² = 640 acres = 2.589988 km².
Mile dates to Roman antiquity; modern exact value standardized in 1959.
Rood to Square Mile conversion formula
The relationship between roods and square miles:
To convert roods to square miles, multiply the value in roods by 0.000390625. To reverse, multiply square miles by 2560.
How to use this converter
Type a value into the calculator. The result in square miles updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Square Mile to Rood converter for the reverse direction.
Step-by-step: convert roods to square miles
- Write down the value in roods (rood).
- Multiply that value by the factor 0.000390625.
- The product is the equivalent value in square miles (mi²).
- To reverse, multiply the square mile value by 2560.
Worked examples
Example 1 — Convert 1 rood to mi²:
1 × 0.000390625 = 0.000390625 mi²
Example 2 — Convert 100 rood to mi²:
100 × 0.000390625 = 0.0390625 mi²
Real-world example — Road-sign distances across systems
A 100-rood road sign converts cleanly into square miles — exactly the conversion drivers planning trips abroad rely on when reading road signs in a different measurement system.
100 rood × 0.000390625 = 0.0390625 mi²
Real-world example — Endurance race distances
A 50-rood cycling or running race converts to a recognizable distance in square miles. Endurance athletes coming from a different measurement system use this conversion to compare training plans across regions.
50 rood × 0.000390625 = 0.01953125 mi²
Real-world example — Maritime exclusion zone
A 200-rood exclusion zone (a common maritime boundary) converts to a different value in square miles that's useful when describing the same zone in everyday land-distance units.
200 rood × 0.000390625 = 0.078125 mi²
Rood to Square Mile conversion table
Standard reference values for converting roods to square miles:
| Rood [rood] | Square Mile [mi²] |
|---|---|
| 0.01 | 3.90625e-6 |
| 0.1 | 3.90625e-5 |
| 1 | 0.000390625 |
| 2 | 0.00078125 |
| 3 | 0.001171875 |
| 4 | 0.0015625 |
| 5 | 0.001953125 |
| 10 | 0.00390625 |
| 20 | 0.0078125 |
| 30 | 0.01171875 |
| 40 | 0.015625 |
| 50 | 0.01953125 |
| 100 | 0.0390625 |
| 500 | 0.1953125 |
| 1000 | 0.390625 |
Frequently asked questions
How many square miles is 1 rood?
How do I convert roods to square miles?
How do I convert square miles back to roods?
How many square miles is 100 roods?
Popular area unit conversions
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Metric / SI (5 units)
Imperial / US Customary (14 units)
Sources & references
Conversion factor (1 rood = 0.000390625 mi²) 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.