Lettable area, explained

Two landlords can quote the same building at the same rate per square metre and mean materially different rent, because they are measuring different things. Four terms do most of the damage.

The four numbers

GLA — gross lettable area

The area you pay for. In SA practice it is measured on the SAPOA basis and generally runs to the inside face of external walls, including internal columns and the space your partitions will stand on.

GBA — gross building area

Everything under roof, including plant rooms, lift shafts and common areas. Always larger than GLA, and not a rental figure — if a rate is quoted against GBA, the rent per usable square metre is higher than it first appears.

Usable area

What your people and racking actually occupy, after columns, ablutions and circulation. The gap between usable and GLA is the number that decides whether a warehouse fits your pallet count.

Rentable area (with a common-area load)

In multi-tenant offices your GLA may be grossed up by a share of lobbies, lifts and corridors. Ask for the load factor as a percentage, not a vibe.

Four questions before you sign

1. Which basis? Ask whether the stated area is measured on the SAPOA basis, and whether it is GLA or grossed-up rentable area.
2. Who measured it, and when? A re-measurement on handover that moves the area moves your rent. Agree in the lease which figure governs.
3. What is excluded? Mezzanines, canopies, yard and hardstand are sometimes in the rate and sometimes charged separately.
4. What else is per-square-metre? Operating costs, rates recovery and utilities are frequently charged on the same area figure, so an area error compounds across every line of the invoice.

Why we show rate per m²

Every listing on this site that states an area also shows the implied rate per square metre, because that is the only number that compares two buildings honestly. Where a lister did not provide an area, we say so on the listing rather than quietly leaving the column blank — and where an area was read from the listing title instead of a stated field, the listing says that too.

This guide is general information, not a measurement certificate or legal advice. The binding area for any specific premises is the one recorded in the lease schedule or the measurement certificate attached to it.