Bangladesh land measurement calculator
Convert a plot between decimal, katha, bigha, acre, square feet and square metres using one consistent set of factors. The page also shows how to start from length × width, and where local custom differs from this model.
Last updated: 2026-09-14
What this calculator does
Land in Bangladesh is talked about in survey units (decimal, acre) and in everyday units (katha, bigha). Deeds, khatian and newspaper ads often mix them. This tool converts one amount into the other units using a single, stated convention.
Enter the number you already know — length and width in feet, square feet, decimal, katha or another supported unit — and read the same area in the other units. A price field, if you use it, only multiplies that area. It is not a legal valuation.
A useful size ladder
- 1 Acre
- 100 Decimal
- about 60.5 Katha*
- 43,560 Square Feet
Units this page uses
| Unit | Also called | Equals in this model |
|---|---|---|
| Decimal | Shotangsho / shatak / cent | 435.6 sq ft · 40.47 sq m · 1/100 acre |
| Katha | Katha / cottah | 720 sq ft · about 1.65 decimal · 16 chhatak |
| Bigha | Bigha | 20 katha · 14,400 sq ft · about 33.06 decimal |
| Acre | Acre | 100 decimal · 43,560 sq ft · about 3.025 bigha |
| Square feet | sft | Base area used for length × width |
| Square metre | sq m | 1 sq m ≈ 10.764 sq ft |
Chhatak, gonda and kora appear in older records. They are converted from the same square-foot base.
What stays stable vs what can change
| Usually stable | Often local |
|---|---|
| 1 acre = 100 decimal = 43,560 sq ft | Size of 1 katha |
| 1 decimal = 435.6 sq ft | How many katha make 1 bigha |
| Length × width in feet → square feet | Names used in a particular haat or mouza |
How the calculation works
Convert through square feet
area in sq ft = amount × factor for the input unit
- Then each other unit = area in sq ft ÷ that unit’s factor.
- From length and width: sq ft = length (ft) × width (ft).
Starting from what you know
- Length and width
- Use the same unit for both sides, usually feet. Irregular plots need more than one rectangle, or a surveyor’s area.
- Square feet
- If the map or brochure already states sft, choose square feet and enter that number.
- Decimal
- Common on khatian and rural sale notices. 100 decimal = 1 acre.
- Katha
- Common in city plots. Confirm whether the seller’s katha is 720 sq ft or another local size.
- Bigha, acre, sq m
- Choose that unit so the tool does not treat a bigha as a katha.
How to use it
- Pick the unit you already have — If the ad says “3 katha”, choose katha. If the RS khatian says 12 decimal, choose decimal.
- Enter the amount — Use the figure from the paper in front of you, not a rounded guess from a neighbour.
- Read the conversion table — Check square feet first. That is the easiest way to compare two plots advertised in different units.
- Optional: add a price per unit — This only estimates a total. Registration, mutation and broker costs are separate.
Worked examples
From katha to decimal and square feet
A Dhaka-area plot is sold as 5 katha, using 720 sq ft per katha.
- Square feet = 5 × 720 = 3,600
- Decimal = 3,600 ÷ 435.6 ≈ 8.26
- Acre = 8.26 ÷ 100 ≈ 0.0826
5 katha ≈ 3,600 sq ft ≈ 8.26 decimal in this model.
From length and width
A rectangular bari measures 60 ft by 40 ft.
- Square feet = 60 × 40 = 2,400
- Decimal = 2,400 ÷ 435.6 ≈ 5.51
- Katha = 2,400 ÷ 720 ≈ 3.33
2,400 sq ft ≈ 5.51 decimal ≈ 3.33 katha (720 sq ft katha).
Practical tips and common mistakes
- Compare two offers in square feet or decimal, not in mixed katha sizes.
- Read the deed unit and the verbal unit separately. People often say katha when the khatian is in decimal.
- For a loan against land, banks will use their own survey, not this estimate. See loan EMI only for repayment maths.
- Treating 1 katha as 1 decimal. They are not the same.
- Using a northern or older bigha size in a Dhaka 720-sq-ft katha calculation.
- Assuming a triangular or road-cut plot equals length × width of the longest sides.
- Taking the calculator total as mutation or registration tax. Those rates change and are office-specific.
FAQ
How many square feet is 1 decimal in Bangladesh?
In the usual survey sense, 1 decimal (shotangsho) is 435.6 square feet, because 1 acre is 43,560 square feet and 100 decimal make 1 acre.
How many katha are in 1 bigha?
In the convention used here, 1 bigha is 20 katha. Other localities may use a different bigha. Check the paper you are reading.
Can I rely on this for a sale deed?
No. Use it to understand units. The registered deed, khatian and a licensed surveyor decide the legal area.