Buying a plot: convert the local units and check the area yourself
A plot reaches you as three numbers: the size in the advert, the size the seller quotes and the area on the record, often in three different units. Put all three into square feet, tape the plot yourself and see which one the ground agrees with.
By Bulan Sarkar · Updated
Write down every area you've been given, with its unit and the state. Convert each to square feet with that state's unit: a West Bengal or Jharkhand katha is 720 sq ft, a decimal, cent or dismil is 435.6 sq ft, a gunta is 1,089 sq ft, a settled Haryana marla is 272.25 sq ft and a gaj is 9 sq ft. Then tape all four sides and one diagonal and add the two triangles. A plot recorded as 5 decimal (2,178 sq ft) that tapes at 2,191 sq ft is fine: 0.6% is tape error. A "30 × 40 site" that tapes 29.5 × 39.5 ft is 34.75 sq ft short, 2.9%, and that is a question for the seller, the land records office and a licensed surveyor before anything is signed.
The decision: check the plot's area yourself before you buy?
Yes, for any plot with four straight sides and its corners pegged or pillared. You need a 30 m tape, a helper, an hour on the plot and the area written on the record. This page takes you from the units on paper to one number in square feet you can trust.
If you're buying a flat, this isn't your page: flats are sold by floor area, not land units. You can also skip the taping when a licensed surveyor has already measured the plot for you and given you a dated sketch with the side lengths, but still convert the units yourself.
Get a licensed surveyor when the tape and the record differ by more than about 1%, when the plot has more than four sides or a curved edge, or when no corner pillars are standing. Ownership, title, mutation and any dispute over the boundary are for a lawyer and the land records office, not a tape.
The steps, in order
Write down every area you've been given
Have ready:the advert or the broker's messagea copy of the record or deed the seller shows youthe state, district and village or ward of the plot
List each figure exactly as written, with its unit: "3 katha" in the advert, "5 decimal" on the record, "about 2,200 sq ft" from the broker. Write down where each one came from and the state it was written in. A bigha or a katha in one state is a different size in the next, so the state matters as much as the number.
Don't convert anything yet. The point of this step is to have every figure on one sheet before anyone rounds it for you.
Convert each figure to square feet with the state's unit
Have ready:the list from step 1the plot area converter, set to the plot's state
The Department of Land Resources keeps one national table of the units used in land records. These are the ones you'll meet most on a house plot:
Unit Where Sq ft Katha West Bengal, Jharkhand 720 Decimal, cent, dismil All states (1/100 acre) 435.6 Gunta Karnataka, Andhra Pradesh, Maharashtra (1/40 acre) 1,089 Marla Haryana, settled records (9 sarsai of 66 × 66 inches) 272.25 Gaj Everywhere (one square yard) 9 The national table rounds a cent to 435 sq ft and a gunta to 100 m². Both come from the acre, so use the exact figures above when you check to the square foot. A bigha is the unit to be careful with: it runs from 9,075 sq ft in Haryana's older records to 27,225 sq ft in parts of Rajasthan. The converter shows each state's own figure and the answer in sq ft, m² and gaj.
Tape the four sides and one diagonal
Have ready:a 30 m (100 ft) steel or fibreglass tapea helper, chalk and four pegsyour phone camera
Start at a corner pillar and tape each side, pulled tight and level, and read every side in the same unit. If the two long sides match and the two short sides match, the plot is a rectangle and the area is length × width. If they don't, tape one diagonal, corner to corner. It splits the plot into two triangles, and each triangle's area comes from its three sides by Heron's formula.
A plot with sides of 40, 55, 42 and 52 ft and a 68 ft diagonal works out to 1,100.0 + 1,091.3 = 2,191.3 sq ft. The plot measuring guide shows the arithmetic line by line. Photograph the tape against each pillar so you have a record of where you measured from.
Compare the tape with the record
Have ready:the record's area in sq ft from step 2your taped area from step 3
Write the two numbers side by side with the difference in square feet and as a percentage of the record. A hand tape can be a couple of inches out on each side. On a 40 × 54 ft plot, 2 inches on both sides moves the area by about 16 sq ft, which is under 1%.
So a gap under about 1% is the tape. The plot recorded as 5 decimal (2,178 sq ft) that tapes at 2,191.3 sq ft is 13.3 sq ft over, 0.6%, and it matches. A gap of a few percent, or a whole local unit (a chhatak is 45 sq ft), is not tape error. The tape can't tell you why: the unit may have been read wrong, a pillar may have moved, or the plot may never have matched the paper. That is for the land records office and a licensed surveyor.
Put the asking price on each area
Have ready:the asking price, as quoted (per katha, per gaj or in total)the three areas in sq ft
Sellers quote per katha, per gaj, per decimal or a lump sum. Turn the quote into a price per square foot, then divide the total by each of your three areas: the advert's, the record's and the taped one. If the three answers differ, you can see in rupees what the difference between the figures is worth.
You don't need a market rate for this. The "30 × 40 site" that tapes 29.5 × 39.5 ft is 1,165.25 sq ft, not 1,200. Whatever price was agreed for 1,200 sq ft, the shortfall is 2.9% of it. Bring that figure to the seller.
Sketch the plot and keep the file
Have ready:the check sheet from this pagea folder for the copies and photos
Draw the plot roughly to shape. Mark the corner letters, every side length, the diagonal, the pillars you found and the road it faces, with the road's width and the plot's frontage on it. Your architect will ask for both. Date the sketch and sign it, and put it in one folder with the copies of the record, the advert and the photos of the tape at each pillar.
If you go ahead, this sheet is the first page of the house file. The house budget plan starts from the plot's area in square feet, and you'll have checked it yourself.
What goes wrong
Variants: what changes the steps
West Bengal and Jharkhand: katha in the deed, decimal on the record
Deeds and adverts often use katha and chhatak (720 and 45 sq ft), while the land record may give the area in decimal or acres. Convert both to square feet before comparing. 3 katha is 2,160 sq ft and 5 decimal is 2,178 sq ft, so the two are close but not equal.
Haryana and the north: marla, kanal and two kinds of bigha
Settled Haryana records use the 66-inch karam: 9 sarsai to a marla (272.25 sq ft), 20 marla to a kanal (5,445 sq ft). Older records use a bigha of 20 biswa, 4.8 to the acre (9,075 sq ft). Read which system the record uses. If a seller's marla isn't 272.25 sq ft, ask which marla they mean.
Bengaluru and the south: a "30 × 40 site" in feet, guntas in revenue records
City sites are sold by their side lengths, so the check is simply taping the two sides. 30 × 40 ft is 1,200 sq ft; 29.5 × 39.5 ft is 1,165.25 sq ft. Land outside the city may be recorded in acres and guntas, 40 guntas to the acre, 1,089 sq ft to the gunta.
Rajasthan: the bigha depends on the jarib
A bigha is one jarib by one jarib. With the 165 ft Shahjahani jarib that is 27,225 sq ft; with the 132 ft Gantari jarib it is 17,424 sq ft. The record or the tehsil office tells you which chain surveyed the village.
Tips and tricks
- Write the state next to every figure on your sheet. The same word can mean a different area in the next state.
- Keep all your working in square feet and convert once at the end. Converting each side separately piles up rounding.
- Tape every side twice, ideally with the same helper, and use the average.
- Take the diagonal that gives two triangles of similar size. A long, thin triangle turns small tape errors into big area errors.
- Photograph the tape's zero against the first pillar and the reading at the second. Two photos per side record exactly where you measured from.
- If the plot faces a road, tape the road's width at both ends of your frontage. It goes on the sketch for your architect.
What we would do
We'd collect every figure first, convert them ourselves in square feet with the state's own unit and tape the plot before talking price. If the tape lands within about 1% of the record, we'd file the sketch and move on to the house budget. If it doesn't, we'd stop there and take the numbers to the land records office and a licensed surveyor, and leave title and ownership questions to a lawyer.
Print the working copy
Plot area check sheet, from the Plot Area Check. One A4 page with tick boxes and blanks; it prints in black and white.
- 1. Every figure on paper
- 2. Tape (same unit for every side)
- 3. Compare and price
- 4. For the sketch
Frequently asked questions
How do I check the plot size before buying?
Is a 30 × 40 site exactly 1,200 sq ft?
How many sq ft is 1 katha, 1 decimal and 1 gunta?
How much difference between the deed and the measured area is normal?
The source we built this on
Read 14 October 2026. The table rounds a cent to 435 sq ft (exact 1/100 acre is 435.6) and a gunta to 100 m² (exact 1/40 acre is 1,089 sq ft or 101.17 m²); this page uses the exact acre fractions. West Bengal's chhatak and bigha come from the WB Directorate of Registration FAQs, cited on the plot area converter. The 1% tape band is our arithmetic for a careful hand tape, not a rule from any code.
This plan covers unit conversion and measuring with a tape. It isn't a survey and says nothing about ownership, title or the legal boundary: a licensed surveyor, the land records office and a lawyer decide those. Watch for open wells, drains and traffic on the road side while taping.