Shop sizes and usable area: 20x70 to 40x80, stairs, columns, NLA

The two numbers on a shop advert are frontage and depth. Multiply them and you get the gross area of one floor: 20x70 is 1,400 sq ft, 22x75 is 1,650 sq ft, 25x80 is 2,000 sq ft, 30x80 is 2,400 sq ft and a 40x80 corner is 3,200 sq ft. The space you can actually trade in is smaller, because the staircase to the upper floors, the rear toilet, the walls and any columns all take a share. Rent on a shoplot is quoted for the whole unit, so the honest comparison is rent per usable sq ft.

Our earlier guide to 22x75, mezzanines and half units explains how to read the sizes. This article works out what is left after the deductions and which trades fit each size.

There is no fixed figure, because every row is built differently. The worked example below shows the method on a 20x70 ground floor where the upper floors are let separately and keep their own staircase at the front. The deductions are assumptions for illustration; measure your own unit.

The staircase also costs you frontage. On many rows the door to the upper floors sits beside your shopfront, so a lot sold as 20 ft wide may give you only about 16 ft of glass. That matters more than the lost floor area for impulse trades.

You cannot remove it, because the upper floors need their own access and fire escape. You can make it work for you:

• Ask whether the staircase door is at the front or the back. A rear staircase keeps your whole frontage.
• Use the space beside or under the stair for storage, a cold room or a staff area rather than customer seating.
• If you rent the whole shoplot, the staircase becomes your internal stair and the separate front door can sometimes be closed off, with the landlord's consent and approved plans.
• Negotiate on usable area. If two similar units ask the same rent and one loses 4 ft of frontage to a stair, that unit is the more expensive one.

On a standard terrace row the columns usually sit in the party walls, so they barely intrude. Wider units, corner lots and units already joined to a neighbour are where columns appear inside the floor. Before you sign:

• Ask for the floor plan and mark every column and beam.
• Measure clear width between columns, not the lot width.
• Lay out the counter, kitchen line, shelving runs or treatment rooms on the plan with the columns in place.
• Check beam depth under the ceiling if you need ducting or a mezzanine.
• Remember that columns are structural. They stay where they are.

A column in the middle of a cafe can be wrapped as a feature. A column in the middle of a supermarket aisle or a dental surgery costs real layout efficiency.

MCE analysis of recent portal adverts, Nov 2026: last 6 months, shop types only, bait and duplicate adverts removed, middle half of asking prices. The typical sizes below show where each unit size appears; the trades are our general guidance, not a rule.

Larger advert sizes often mean a corner, an extended rear or two units already joined, so confirm what you are looking at. Trade-specific needs are in what shop a cafe, clinic or salon needs.

• Gross floor area (GFA) is measured to the outside of the walls and includes stairs, toilets, columns and walls. Shop adverts and titles usually quote a figure close to this.
• Net lettable area (NLA) is the area a tenant actually occupies and can use, measured inside the walls, without shared stairs, lift shafts and common corridors. Malls and office towers usually quote rent on NLA.

On a ground-floor shoplot, the landlord asks a monthly figure for the unit. The "RM per sq ft" you see in adverts and in our shop rent index is simply that rent divided by the advertised size, which is closer to gross than net. Two practical consequences:

1. When you compare a shoplot with a mall lot, convert both to rent per usable sq ft, or the shoplot looks dearer than it is.
2. When you compare two shoplots, work out usable area for each and divide. The PSF calculator does the arithmetic, and the rent affordability calculator checks the result against your sales.

Tell us your trade and the usable area you need, and MCE will shortlist ground floors that fit. Start on the tenants page.

Written by Tok Ginstee (REN 37505), CID Realtors Sdn Bhd (E (1) 1855). Updated November 2026.