Convert Rood to Square Perch
Convert roods to square perches instantly. 1 rood = 40 square perch — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Square Perch 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 Perch
A square perch is identical to a square rod, equal to approximately 25.293 m². 'Perch' is the older English regional name for the same unit.
Identical in value to square rod and square pole; differs only in regional naming preference. 'Perch' is more commonly used in British and Irish historical contexts.
Square perches survive in some historical British property records, particularly in Ireland where the unit had legal status until the metric transition.
Standardized via the 1959 International Yard and Pound Agreement.
Rood to Square Perch conversion formula
The relationship between roods and square perches:
To convert roods to square perches, multiply the value in roods by 40. To reverse, multiply square perches by 0.025.
How to use this converter
Type a value into the calculator. The result in square perches 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 Perch to Rood converter for the reverse direction.
Step-by-step: convert roods to square perches
- Write down the value in roods (rood).
- Multiply that value by the factor 40.
- The product is the equivalent value in square perches (perch²).
- To reverse, multiply the square perch value by 0.025.
Worked examples
Example 1 — Convert 1 rood to perch²:
1 × 40 = 40 perch²
Example 2 — Convert 100 rood to perch²:
100 × 40 = 4000 perch²
Real-world example — Road-sign distances across systems
A 100-rood road sign converts cleanly into square perches — exactly the conversion drivers planning trips abroad rely on when reading road signs in a different measurement system.
100 rood × 40 = 4000 perch²
Real-world example — Endurance race distances
A 50-rood cycling or running race converts to a recognizable distance in square perches. Endurance athletes coming from a different measurement system use this conversion to compare training plans across regions.
50 rood × 40 = 2000 perch²
Real-world example — Maritime exclusion zone
A 200-rood exclusion zone (a common maritime boundary) converts to a different value in square perches that's useful when describing the same zone in everyday land-distance units.
200 rood × 40 = 8000 perch²
Rood to Square Perch conversion table
Standard reference values for converting roods to square perches:
| Rood [rood] | Square Perch [perch²] |
|---|---|
| 0.01 | 0.4 |
| 0.1 | 4 |
| 1 | 40 |
| 2 | 80 |
| 3 | 120 |
| 4 | 160 |
| 5 | 200 |
| 10 | 400 |
| 20 | 800 |
| 30 | 1200 |
| 40 | 1600 |
| 50 | 2000 |
| 100 | 4000 |
| 500 | 20000 |
| 1000 | 40000 |
Frequently asked questions
How many square perches is 1 rood?
How do I convert roods to square perches?
How do I convert square perches back to roods?
How many square perches is 100 roods?
Popular area unit conversions
Convert Rood to other area units
Show all Rood conversions
Metric / SI (5 units)
Imperial / US Customary (14 units)
Sources & references
Conversion factor (1 rood = 40 perch²) 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.