Square Inches to Square Rods (in² to sq rd)

1 square inch equals 0.00002550760127 square rods (rounded).

1 square inch = 0.00002550760127 square rods

How to convert square inches to square rods

To convert square inches to square rods, multiply the number of square inches by 0.00002550760127. The factor is rounded to 10 significant digits. To go the other way, multiply square rods by 39,204.

square rods = square inches × 0.00002550760127

Example: 10 square inches = 0.0002550760127 square rods.

About these units

Square Inch (in²)

US & ImperialCurrent unit

A square one inch on a side, exactly 6.4516 cm². Used for small parts and for pressure (pounds per square inch).

Latin uncia, one twelfth, gave English the inch, which Old English borrowed as ynce. A statute of Edward II in 1324 defined it as three barleycorns, dry and round, set end to end, and the barleycorn remained the base for centuries after 1066. The modern square inch rests on a 20th-century agreement: the United States adopted a yard of exactly 0.9144 meter on 1 July 1959, the United Kingdom followed effective 1 January 1964, and the inch became exactly 25.4 mm.

Squaring that gives exactly 6.4516 cm² for one square inch, and one square meter is about 1,550 of them. Its best-known descendant is the pound per square inch, psi, the pressure unit still used for American tires and air tanks: atmospheric pressure at sea level is about 14.7 psi, a car tire is typically inflated to around 32 psi above the surrounding air, and one psi is about 6.895 kilopascals. The square inch itself is common in the US and UK for small parts and printed material.

1 square inch = 0.00064516 square meters (exactly).

Sources: Wikipedia: Square inch; Wikipedia: Inch; Wikipedia: Pounds per square inch

Square Rod (sq rd)

US & ImperialTraditional unit (still used in some regions)

30.25 square yards (25.29 m²), also called a perch. 160 square rods make an acre.

Perch is the older name for this small square, and it traces back to the Roman pertica, a measuring pole. The word rod became the preferred surveyors' term in England, where land measurers carrying rods, poles or knotted cords were in demand after Henry VIII took over church estates in 1536. A square rod is the square on a rod of 16.5 feet, which works out to 272.25 square feet, or 30.25 square yards.

The odd-looking number makes sense through the acre. Edmund Gunter's 66-foot chain is four rods long, so a square chain holds 16 square rods, and ten square chains make an acre. That means 160 square rods fill an acre, and a rood holds 40. Metric equivalents are about 25.29 square meters, a little under the floor area of a small garage. Rods and perches turned up in deeds, tax records and plot descriptions for centuries, and a few English-speaking regions still quote small building plots in perches.

1 square rod = 25.29285264 square meters (exactly).

Sources: Wikipedia: Rod (unit); Wikipedia: Chain (unit); Wikipedia: Acre

Related conversions

See all area units.