You find a listing for a 35 sqm condo near BTS Thong Lo priced at 18,000 THB per month. Sounds reasonable. You show up for the viewing and the place feels tiny. Like, noticeably smaller than your friend's 32 sqm unit in Lumpini Park Rama 9. What happened? Welcome to one of the most common traps in Bangkok's rental market: the gap between advertised square meters and actual livable space. Knowing how to verify your bangkok condo sqm check before signing a lease can save you from months of frustration in a unit that feels like a shoebox.

Why Advertised SQM Rarely Tells the Full Story

In Bangkok, the square meter number you see on a listing usually refers to the total or "gross" area. This measurement includes the thickness of the walls, the balcony, and sometimes even a portion of shared common areas. The actual usable floor space inside the unit, the part where you can place furniture and walk around, is often 10 to 20 percent smaller.

Here is a real example. A popular listing for a unit at Life Asoke Hype near MRT Phetchaburi might advertise 36 sqm. But once you subtract the balcony (about 3 sqm), the wall thickness (roughly 1.5 sqm), and an oddly shaped hallway leading to the bathroom, the space where you actually live is closer to 30 or 31 sqm. That is a meaningful difference when you are paying 20,000 to 25,000 THB per month.

Developers and agents are not necessarily lying. They are just using the measurement that makes the number look best. Your job as a renter is to understand the difference and verify for yourself.

Total Area vs Usable Area: What Each Actually Means

Let's break this down simply. Total area, sometimes called gross area, is measured from the outer edge of one wall to the outer edge of the opposite wall. It is the number on the title deed and the number most listings use. Usable area, sometimes called net area or "living area," only counts the interior floor space you can actually use.

Say you are comparing two units near BTS Ekkamai. The first is a studio at Noble Reveal listed at 34 sqm, and the second is a one bedroom at Mori Haus listed at 38 sqm. On paper, Mori Haus wins. But Noble Reveal has a compact, efficient layout with almost no wasted hallway space and a small balcony. Mori Haus has a generous balcony (about 5 sqm), thick concrete walls, and a long entryway. The usable interior of both units might end up being nearly the same, around 29 to 30 sqm.

This is why you should never compare condos by listed sqm alone. Layout efficiency matters just as much as raw numbers.

How to Measure a Unit Yourself Before Signing

You do not need fancy equipment. A basic laser distance measurer costs about 400 to 800 THB on Lazada and fits in your pocket. Bring it to every viewing. Alternatively, a regular tape measure works fine if you have someone to help you hold the other end.

Start by measuring the main living area from interior wall to interior wall. Then measure the bedroom, bathroom, kitchen area, and balcony separately. Add up everything except the balcony. That gives you a realistic usable figure. Compare this to the listed total. If a unit on Soi Sukhumvit 24 is advertised at 45 sqm but your interior measurements add up to 35 sqm of livable space, you know exactly what you are working with.

Also pay attention to ceiling height. A unit at Ashton Asoke with 2.7 meter ceilings will feel significantly more spacious than a unit at an older building on Soi Ratchadaphisek 17 with 2.4 meter ceilings, even if both are technically the same sqm. Volume matters for how a space feels day to day.

Ask for the Floor Plan and Title Deed Details

Every condo unit in Thailand has an official floor plan registered with the Land Department. This document shows the exact dimensions and total area as recorded on the title deed (chanote). You have every right to ask the landlord or agent to provide it. If they hesitate or say they do not have it, that is a red flag.

Consider a scenario where you are looking at a two bedroom unit at Ideo Q Siam near BTS Ratchathewi, listed at 65 sqm for 35,000 THB per month. The floor plan reveals that 7 sqm is balcony space and the unit includes an unusually thick structural column cutting into the living room. Suddenly, 65 sqm becomes about 55 sqm of genuinely livable space. Without seeing the floor plan, you would have signed the lease expecting more room than you are actually getting.

Cross reference the floor plan measurements with your own on site check. Discrepancies between the two are rare but not unheard of, especially in older buildings along Silom or Sathorn where renovations may have altered interior walls.

Red Flags That a Unit Is Smaller Than Advertised

Watch for listings that use ultra wide angle photos. If the living room looks massive in pictures but the sofa appears weirdly stretched and distorted, the photographer is using a lens trick to make the space look bigger. Visit in person before committing.

Another red flag is when a listing rounds up aggressively. A unit that is 28.5 sqm on the title deed somehow becomes "approximately 30 sqm" in the ad. That 1.5 sqm difference is basically a closet's worth of space disappearing from your expectations. You will see this a lot in popular areas like Ari and BTS Saphan Khwai where studios in the 20,000 to 25,000 THB range are in high demand and agents want every listing to look competitive.

Trust your eyes and your measurements over any listing description. If a place feels cramped during a 15 minute viewing, it will feel even more cramped after you have moved in all your stuff.

Getting the real size of a condo before you sign is one of the simplest ways to protect yourself as a renter in Bangkok. Bring a laser measurer, ask for the floor plan, and always compare usable space rather than headline numbers. A little effort during your search saves you from a year of regret in a unit that never quite felt right. If you want listings that show transparent, verified details so you can compare honestly, check out superagent.co and let the platform do the heavy lifting for you.