Before the first line is drawn: how FAR decides your building

Every family that buys land in Dhaka carries the same quiet hope: one day, a home of our own, built right. Between that hope and the building stands a number most people have never heard of. Let me tell it as a story. Call him Shahin bhai.

Shahin bhai and his younger brother put twenty years of savings into a 5-katha plot in Bashundhara. Within a month, a developer came with a joint-venture offer. "How many floors will you give us?" Shahin bhai asked. The developer said nine. A friend said ten was possible. Nobody showed him the calculation.

How much can this land carry?

When he came to us, the first thing we told him was this: the answer does not start with floors. It starts with FAR, the floor area ratio. FAR is the counted floor area a building may have, divided by the area of its plot.

His 5 katha is about 3,600 sq ft. At a FAR of 3.5, the land can carry about 12,600 sq ft of counted floor area. Every floor, every flat and every price comes after that number.

Two numbers, not one

Under Imarat Nirman Bidhimala 2025, every plot has two FAR figures. One comes from the Detailed Area Plan (DAP 2022–2035) for its block. The other comes from the width of the road in front of its gate.

The lower of the two is the base. The higher is the ceiling. Incentives in the DAP can lift a project from the base towards the ceiling, never above it. Only block development, urban regeneration areas and transit-oriented development may go up to 0.5 beyond. And if the two figures are within 0.1 of each other, the plot simply gets the higher one.

The road outside the gate

Shahin bhai had always thought of his road as just a road. In the rules, it is half of his answer.

For flats in the highest-density zone, road-based FAR is 3.25 on a 6 m road (about 20 ft), 3.50 on 9 m (about 30 ft), 4.00 on 12 m, 4.25 on 18 m and 4.75 on 24 m or wider. Between two steps it rises in proportion: a 25 ft road gives about 3.39, not 3.25. If a plot faces two roads, the wider one counts.

His road was 30 ft wide and his block's DAP figure was higher, so the road set his base: 3.50.

If the master plan will widen a road, FAR is the average of today's width and tomorrow's, and the land given up for it comes back as three times its area in floor area.

What is not counted

Then came the good news. Some spaces do not use up FAR at all:

• The stair, up to the size of the typical-floor stair
• The lift machine room
• Floors used only for parking, including up to a quarter of that floor for services, stair and lift
• Electro-mechanical rooms such as the generator and pump room
• Cantilevered balconies and hanging planters, each up to 2.5% of that floor's area

Used well, these rules give a family more space to live in, not less.

Six floors or eight?

Floor area becomes floors through ground coverage. On a plot of his size, 268 to 402 m², the building may cover between 46.5% and 62.5% of the land.

At the largest footprint, 12,600 sq ft makes 6 floors. At the smallest, it makes 8, because in RAJUK practice a part floor counts as a full one.

That was the moment Shahin bhai stopped asking "how many floors?" and started asking "what kind of home?". Fewer, wider floors, or more, slimmer ones with open ground, light and air around them.

Before you sign

He went back to the developer with the numbers, and the conversation changed. This time the share, the unit sizes and the open ground were agreed on facts, not promises.

A building is not just four walls. It is a place to breathe. Before you sign, check your plot in our free FAR Calculator. For a full study of your land, talk to SLATE.