Floor Area Ratio Calculator

Floor Area Ratio Formula

Worked Example

A 1000 m² plot with FAR 2.5 and 40 % ground coverage:

1. Built-up area = FAR × plot = 2.5 × 1000 = 2500 m²
2. Floors = FAR ÷ ground coverage = 2.5 ÷ 0.4 = 6.25

Floors at full coverage FAR ÷ coverage: 6.25 · Whole floors possible: 6 · Open area at ground level: 600 m²

GATE tip

Floors = FAR ÷ coverage: with FAR 2.5 and 40 % coverage, 6.25 floors, so six full floors and a partial seventh.

More Planning, Housing and Valuation Calculators

• Residential Density Calculator

  Density = dwelling units / area

  gross uses the whole site; net only the residential plots

  Example: 300 dwellings of 4.5 persons on a 2 ha site with 1.2 ha in plots: Gross density = 150 DU/ha.

  Open the residential density calculator →

• Years’ Purchase Calculator

  Value = net income × YP

  YP = 1/i (perpetual), (1 − (1 + i)^−n)/i (n years), 1/(i + s/((1 + s)ⁿ − 1)) dual rate

  Example: A freehold earning a net 1,20,000 a year at 8 %: Capitalised value = 1500000.

  Open the years’ purchase calculator →

Frequently asked questions

Sources

• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.