Sri Lanka Land Area Converter — Perches to Acres, Hectares & More

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.

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.