Work out efficiency ratio of floor plate instantly with clear inputs, formula shown and shareable results.
Floor plate efficiency is net usable area as a share of gross, after removing the core of lifts, stairs, risers and toilets, plus primary circulation. Efficient office plates achieve 80-85 percent; anything below 75 percent means tenants are paying for a lot of space they cannot occupy.
Efficiency
Efficiency = (gross - core - circulation) / gross x 100
Efficiency = (gross - core - circulation) / gross x 100. Floor plate efficiency is net usable area as a share of gross, after removing the core of lifts, stairs, risers and toilets, plus primary circulation.
A deep core relative to a small floor plate, awkward geometry, and multiple stair cores driven by escape distances. Tall towers with small floors are structurally forced into low efficiency.
This calculator takes 3 inputs: Gross floor area, Core area, Circulation area. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.