Quick answer: To convert Decimal to Katha in Bihar, divide the Decimal by 3.415.
So 10 Decimal ÷ 3.415 = 2.93 Katha — roughly 2 Katha, 18 Dhur and 11 Dhurki.
That one line is enough for a rough estimate. It is not enough if you are signing a sale deed, and the rest of this guide explains why. Bihar does not use one single Katha everywhere, and picking the wrong rate is exactly how two people end up arguing over the same plot with two different numbers — both of them “correct” on paper.
The formula, in plain words
Katha = Decimal ÷ 3.415
And if you want the answer the way it is actually written in most land records — in Katha, Dhur and Dhurki — you split the result like this:
- The whole number is your Katha.
- Multiply what is left over by 20. That whole number is your Dhur (1 Katha = 20 Dhur).
- Multiply the new leftover by 20 again. That is your Dhurki (1 Dhur = 20 Dhurki, so 1 Katha = 400 Dhurki).
A worked example: 25 Decimal
This is the amount that comes up again and again, so let’s do it slowly.
- 25 ÷ 3.415 = 7.32 Katha
- Keep the 7. You have 0.32 Katha left.
- 0.32 × 20 = 6.42 Dhur → keep 6 Dhur. You have 0.42 Dhur left.
- 0.42 × 20 = 8.4 Dhurki → about 8 Dhurki.
25 Decimal = 7 Katha, 6 Dhur and 8 Dhurki (approximately).
If you would rather not do this by hand, our free Katha to Decimal Converter works in both directions and breaks the result into Katha, Dhur and Dhurki for you.
Decimal to Katha conversion table (Bihar, 3.415 rate)
| Decimal | Katha | Katha · Dhur · Dhurki (approx.) |
|---|---|---|
| 1 Decimal | 0.29 Katha | 0 Katha, 5 Dhur, 17 Dhurki |
| 2 Decimal | 0.59 Katha | 0 Katha, 11 Dhur, 14 Dhurki |
| 5 Decimal | 1.46 Katha | 1 Katha, 9 Dhur, 6 Dhurki |
| 10 Decimal | 2.93 Katha | 2 Katha, 18 Dhur, 11 Dhurki |
| 25 Decimal | 7.32 Katha | 7 Katha, 6 Dhur, 8 Dhurki |
| 50 Decimal | 14.64 Katha | 14 Katha, 12 Dhur, 17 Dhurki |
| 100 Decimal (1 Acre) | 29.28 Katha | 29 Katha, 5 Dhur, 13 Dhurki |
Read the last row carefully. A lot of people expect 100 Decimal to come out as a neat round number of Katha. At the 3.415 rate, it doesn’t — and that is the first clue that a different local rate may be in play on your document. Which brings us to the part most converter pages skip.
Why your number might not match your neighbour’s
Here is the honest problem with Katha: it is a traditional unit, not a standardized one. Its size was fixed locally, long ago, by the length of the measuring chain used in that area. So “1 Katha” does not cover the same ground in every district.
Two rates are commonly used in Bihar:
- 3.415 Decimal per Katha — the practical rate used across much of Bihar, and the rate used in the table above. It works out to a Katha of about 1,487.6 square feet.
- 3.125 Decimal per Katha — the rate you get from a Katha of exactly 1,361.25 square feet (1,361.25 ÷ 435.6 square feet per Decimal = 3.125). This is the standard associated with the Patna/Arrah side.
Watch what that difference does to a real plot:
10 Decimal at 3.415 = 2.93 Katha
10 Decimal at 3.125 = 3.20 Katha
Same land. Two different answers, almost a third of a Katha apart. Neither person made an arithmetic mistake — they just used different local standards.
So before you convert anything that matters, do this one thing first: look at your Jamabandi or Khatauni and see which standard your own records are already using. Match that. Do not borrow a rate from a website (including this one) just because it was the first result on Google.
Three mistakes that cause most conversion disputes
1. Converting with one rate and registering with another.
Someone checks a plot online at 3.415, agrees on a price, and then finds the deed was prepared at the local rate. The land hasn’t changed. The expectation has. Settle the rate before you settle the price.
2. Rounding too early.
If you round 7.32 Katha to “about 7.5” at the first step and then convert the Dhur and Dhurki from that rounded figure, the error compounds. Keep at least two decimal places until the very last step, and only then round the Dhurki.
3. Forgetting that Decimal and Dismil are the same thing.
In Bihar, Decimal is also written as Dismil or Shotangsha in older documents. It is one unit with three names, not three different units. If your grandfather’s record says Dismil and the new record says Decimal, the numbers should still line up — and if they don’t, that is a genuine discrepancy worth asking the revenue office about.
For reference: 1 Decimal = 435.6 square feet = 1/100 of an acre.
When a calculator is enough — and when it isn’t
A converter like ours is perfect for the everyday jobs: checking a listing, comparing two plots, understanding an old family record, or getting a fair estimate before you talk to a broker.
It is not enough for the final number on a registration, a mutation (Dakhil Kharij), a partition between family members, or a bank loan against the land. For those, get the figure confirmed by your local revenue office (the Bihar Bhumi portal is where land records are maintained) or a registered land surveyor who will measure on the ground. A five-minute verification at that stage is a lot cheaper than correcting a deed later.
Frequently asked questions
How many Katha is 1 Decimal in Bihar?
1 Decimal = about 0.29 Katha at the commonly used 3.415 rate. In the units used in land records, that is roughly 5 Dhur and 17 Dhurki. At the Patna-side 3.125 rate, 1 Decimal = 0.32 Katha.
How do I convert Decimal to Katha manually?
Divide the Decimal by 3.415. For example, 10 ÷ 3.415 = 2.93 Katha. Then multiply the decimal part by 20 to get Dhur, and the next remainder by 20 again to get Dhurki.
Is 1 Katha the same in every Bihar district?
No, and this is the single most important thing in this guide. The size of a Katha varies by local tradition, which is why both 3.415 and 3.125 Decimal per Katha are in genuine use. Always confirm which standard your district and your own land record use.
What is 1 Acre in Katha in Bihar?
It depends on the rate, and any page that gives you one answer without saying that is oversimplifying. 1 Acre = 100 Decimal, which is 29.28 Katha at the 3.415 rate, or exactly 32 Katha at the 3.125 rate.
Can I use this conversion for land registration?
Use it for estimation and cross-checking, yes. For registration, stamp duty, or mutation, verify the final figure with the Bihar Revenue Department or a registered surveyor. Conversion rates can differ by district and by document.
Bottom line
Decimal to Katha in Bihar is a one-step formula — divide by 3.415 — sitting on top of one genuine complication: Katha is not the same size everywhere. Learn the formula, check which rate your own record uses, and you will not be caught out by a number that looks right but belongs to a different district.
Want the reverse calculation instead? Head to the Katha to Decimal Converter — it converts both ways and shows the full Katha, Dhur and Dhurki breakdown instantly.
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