You are buying a flat, so why learn about acres and guntha? Because the land under your building is described in those units in the title deeds, the RTC and the RERA registration. A little arithmetic helps you read those papers and judge how crowded or spacious a project really is.
The numbers to remember
| Unit | Square feet | Square metres |
|---|---|---|
| 1 acre | 43,560 | 4,046.86 |
| 1 guntha (1/40 acre) | 1,089 | 101.17 |
| 1 square yard | 9 | 0.8361 |
| 1 square metre | 10.7639 | 1 |
These are fixed ratios, not estimates. You can check each one on a calculator.
Why a guntha is 1,089 square feet
An acre is 43,560 square feet. A guntha is one fortieth of that, so 43,560 ÷ 40 = 1,089. Picture a square 33 feet on each side; 33 × 33 = 1,089. Forty of those squares make an acre. You may see it spelled gunta or guntha. The size is the same.
Reading an RTC extent without a mistake
Karnataka's record of rights (RTC) writes land as acres and guntha separated by a dot. This catches many people out.
- 1.20 means 1 acre 20 guntha = 60 guntha = 65,340 sq ft. It does not mean 1.2 acres.
- 0.30 means 30 guntha = 32,670 sq ft, which is three quarters of an acre.
- 2.00 means exactly 2 acres = 87,120 sq ft.
The number after the dot counts guntha and never goes above 39. Reading 1.20 as a decimal would understate the land by 12 guntha, more than 13,000 square feet.
A worked example: judging how dense a project is
Our own project, The Shalott Marque, has 54 homes on 0.75 acres. Here is how the numbers work out:
- 0.75 acre × 40 = 30 guntha. In RTC style that would be written 0.30.
- 30 × 1,089 = 32,670 square feet of land.
- 54 homes on 0.75 acre is 72 homes per acre.
You can do the same sum for any project you are considering: take the land area from the RERA registration and the number of units, and compare. Fewer homes per acre generally means fewer neighbours sharing the lifts, parking and open spaces. It is one useful signal among many, not the whole story.
Practice conversions you can check yourself
Try these on your phone calculator. Each uses only the fixed ratios above.
- 20 guntha to square feet: 20 × 1,089 = 21,780 sq ft, exactly half an acre.
- 20 guntha to square metres: 21,780 ÷ 10.7639 ≈ 2,023 square metres.
- 1,500 sq ft to square yards: 1,500 ÷ 9 ≈ 167 square yards. Brokers sometimes quote plots this way.
- A 1,200 sq ft flat in square metres: 1,200 ÷ 10.7639 ≈ 111.5 square metres. Your agreement may state carpet area in square metres, so this one is worth knowing.
Where these units appear when you buy a flat
- RERA registration: the total land area of the project.
- Title deeds and RTC: each survey number's extent, in acres and guntha.
- Your sale deed: your undivided share of land, often in square feet or square metres.
- Your agreement for sale: the carpet area of your flat, which is a floor area, not land.
Ankanam: a word, not a measurement
Brokers sometimes talk in ankanam. Around Bengaluru it is often taken as 72 square feet (6 feet by 12 feet). But no standard fixes it, and it does not appear in the records that settle disputes. If you hear ankanam, ask for the area as written in the deed and the RTC.
Why the law prefers metric
Section 10 of the Legal Metrology Act, 2009 requires dimensions in transactions to be stated in standard units, and the standard unit of area is the square metre. Older units live on in speech and old records, but any document should be able to give you the metric figure.
Which number wins if documents disagree
The Karnataka Land Revenue Act, 1964 governs the record of rights, and section 133 presumes an RTC entry is correct until proved otherwise. In practice, trust the registered deed and the RTC first, then the government survey sketch, and a brochure last.
Two more units you may meet
- Hectare: 10,000 square metres, about 2.471 acres. It appears in some government and planning documents.
- Cent: one hundredth of an acre, so 435.6 square feet. It is common in Kerala and Tamil Nadu, and buyers moving from those states sometimes use it out of habit. It is not a Karnataka revenue unit.
Your undivided share of land, explained
When you buy a flat, you usually also get an undivided share (often called UDS) of the land the building stands on. "Undivided" means you own a fraction of the whole plot together with everyone else, not a marked piece of it. The sale deed should state this share.
Here is an illustrative example with made-up numbers, not any real project. A building of 80 flats stands on 1 acre, or 43,560 square feet. If the land were shared equally, each flat's share would be 43,560 ÷ 80 = 544.5 square feet. In practice the share is often in proportion to each flat's area, so a larger flat gets a larger share. If your flat is 1,000 square feet out of a total of 88,000 square feet of flats, your share is 1,000 ÷ 88,000 of 43,560, which is about 495 square feet.
You do not need to argue about the exact figure. But you should check that it is written down, that the total of all shares does not exceed the land, and that the land figure matches the RERA registration.
Step by step: checking the land figures for a project
- Find the land area on the project's RERA registration page.
- Convert it to square feet using the table above, reading any RTC-style figure as acres and guntha.
- Divide by the number of homes to get a simple homes-per-acre figure.
- Read your draft sale deed for your undivided share and check it is in a sensible proportion.
- Ask your lawyer to match the survey numbers and extents in the title documents to the RERA figure.
Common mistakes to avoid
- Reading 1.20 as 1.2 acres. It is 1 acre 20 guntha, a 13,068 square foot difference.
- Trusting a broker's ankanam figure. Ask for the area in the deed.
- Comparing land per home without checking phases. A project may register one phase on part of a larger plot.
- Confusing land area with flat area. They answer different questions.
Do not mix up land and flat area
Guntha and acres measure land. The area of your flat is a different thing: carpet area, defined in section 2(k) of the Real Estate (Regulation and Development) Act, 2016 as the net usable floor area inside the flat. The two never convert into each other.
A quick checklist for your file
- Land area from the RERA page, written in square feet and square metres
- Survey numbers and extents from the title documents, read as acres and guntha
- A homes-per-acre figure you worked out yourself
- Your undivided share from the draft sale deed
- Your flat's carpet area in square metres and square feet
With these five lines on one page, most land and area questions answer themselves.
See the project details, including its RERA registration, on The Shalott Marque page.