Perch to Square Feet & Hectare to Perch — Sri Lanka Land Converter

Sri Lanka uses two parallel land-area systems at the same time. The older British system — perches, roods, acres — is what every property ad and old deed quotes, because the Land Reform Commission and Registrar of Lands records were laid down before metrication. The newer metric system — square metres and hectares — is what the Survey Department writes on cadastral maps issued after 2003 and what the Institute of Surveyors uses for GIS work. This converter bridges the two, plus the related units (square feet, square yards, cents) people encounter day-to-day.

The base unit internally is the square metre. Every conversion goes through it using SI-exact factors:

• 1 ft = 0.3048 m (exact) → 1 sq.ft = 0.09290304 m²
• 1 yd = 0.9144 m (exact) → 1 sq.yd = 0.83612736 m²
• 1 perch = 30.25 sq.yd = 25.29285264 m²
• 1 rood = 40 perches = 1,011.7141056 m²
• 1 acre = 4 roods = 160 perches = 4,046.8564224 m²
• 1 hectare = 10,000 m² (SI exact)
• 1 cent = 1/100 acre = 40.468564224 m² = 1.6 perches

The calculator follows a three-step algorithm: (1) parse the input amount and source unit, (2) multiply by that unit's square-metre factor to get a canonical area in m², (3) divide that m² value by every other unit's factor to populate the result grid. Because all factors are stored as exact rationals, the order of operations doesn't accumulate floating-point error: 15 perches converted to square feet via metres yields the same 4,083.75 as the imperial shortcut 15 × 272.25.

The page also runs an independent cross-check: it computes the perch-to-square-feet conversion using the imperial-only path (1 perch = 16.5 ft × 16.5 ft = 272.25 sq.ft, no SI involved) and compares it to the metric path. The two must agree to floating-point precision; any divergence would signal a bug. For deed notation, the algorithm splits a perch total back into the "a-r-p" triplet using floor-division: acres = ⌊perches ÷ 160⌋, then roods = ⌊remainder ÷ 40⌋, then the residual perches with up to three decimal places — so parsing 2a-1r-30pand re-encoding the resulting 390 perches produces 2a-1r-30p again with zero loss.

A hectare is 10,000 m² and a perch is 25.29285264 m², so a hectare is 10,000 ÷ 25.29285264 = 395.3686 perches — 395.37 for everyday use. Multiply any hectare figure by 395.37: 2 ha = 790.74 perches, and half a hectare = 197.68 perches. In the older system the same area is 2.4711 acres.

1 hectare = 395.3686 perches = 2.4711 acres.

A perch is a square 16.5 ft on each side, so one perch is 16.5 × 16.5 = 272.25 square feet. The figure is exact rather than rounded, because the perch is defined in feet and never has to pass through metres. Multiply any perch count by 272.25: 10 perches = 2,722.50 ft², 15 perches = 4,083.75 ft², 20 perches = 5,445 ft².

1 perch = 272.25 square feet = 30.25 square yards.

Going the other way, divide square feet by 272.25. A 1,000 ft² floor plate sits on 3.6731 perches, 2,400 ft² on 8.8154 perches, and 5,000 ft² on 18.3655 perches. A useful whole-number landmark: 2,722.5 ft² is exactly 10 perches.

1 square foot = 0.00367309 perches.

An acre is 4 roods and a rood is 40 perches, so an acre is 4 × 40 = 160 perches exactly — the benchmark every Sri Lankan deed extract and property ad is built on. So 2 acres = 320 perches, 5 acres = 800 perches, and half an acre = 80 perches. To answer the reverse question — how many acres 160 perches comes to — divide by 160: 160 ÷ 160 = exactly 1 acre, which is 43,560 ft² or 4,046.8564 m².

1 acre = 160 perches = 4 roods = 43,560 square feet.

Divide perches by 395.3686, or multiply by 0.0025292853. On that basis 100 perches = 0.2529 ha, 160 perches (one acre) = 0.404686 ha, and 1,000 perches = 2.5293 ha. The converter above runs the same figure through the exact 25.29285264 m²/perch factor rather than a rounded one.

1 perch = 0.0025292853 hectares = 25.29285264 m².

A rood is a quarter-acre: 40 perches, 10,890 square feet, or 1,011.7141 m². In the acres-roods-perches notation on a deed it is the middle figure, so 0a-2r-0p is 80 perches and 1a-1r-0p is 200 perches. The rood figure in a deed line never runs past 3, because a fourth rood carries into one acre.

1 rood = 40 perches = 10,890 square feet = 1,011.7141 m².

Every row below is a conversion the tool above produces, written out so it can be read without touching the keyboard. Perch counts to 20 cover nearly every advertised town plot; 40 perches is one rood and 160 perches is one acre.

Acres are how plantation and farmland is quoted, and 160 perches to the acre makes the arithmetic exact at every row.

Hectares are what the Survey Department writes on a cadastral map, so this is the table to use when a surveyed figure has to be quoted back in perches.

The table below gives the most-searched unit relationships for Sri Lankan land — useful for quick checks on property ads, deed extracts, and bank valuations.

Factors are SI-exact. For full precision and non-standard inputs, use the converter above.

• Survey Department of Sri Lanka — official surveying body
• Sri Lanka Land Reform Commission — uses acres/roods/perches
• Institute of Surveyors Sri Lanka — metric cadastral conventions
• NIST — SI unit reference (1 yd = 0.9144 m exact)

Conversion factors on this page were last cross-checked against official sources on 2026-05-11. The SI definitions are exact and do not change; this page is reviewed annually for any new local convention.