How to Convert Bigha, Katha, and Dhoor into Square Feet & Decimal in Bihar and UP?
In northern and eastern Indian states such as Bihar, Uttar Pradesh (UP), Jharkhand, West Bengal, and Assam, traditional agricultural and residential land transactions still rely heavily on regional units like Bigha, Katha (Kattha), Dhoor (Dhur), Dhurki, Biswa, and Decimal (Dismil). However, when registering property (Kewala/Registry), applying for bank home loans, or approving building maps, government revenue departments require measurements in standard units like Square Feet (Sq.Ft), Square Meters (Sq.Mt), Decimal, or Acres.
Our free online Bihar/UP Land Unit Converter bridges this gap by allowing buyers, sellers, and Amin surveyors to select their regional Katha/Laggi preset and instantly get exact conversions across six standard units.
Standard Bihar & UP Land Measurement Conversion Table (2026)
Based on the standard 5.5 Haath Laggi commonly used in Patna and central Bihar revenue records, here is the official conversion reference table:
| Regional Land Unit | Sub-Unit Equivalent | Area in Square Feet (Sq.Ft) | Area in Decimal (Dismil) |
|---|---|---|---|
| 1 Dhoor (Dhur) | 20 Dhurki | 68.0625 Sq.Ft | 0.156 Decimal |
| 1 Katha (Standard 5.5 Haath) | 20 Dhoor | 1,361.25 Sq.Ft | 3.125 Decimal |
| 1 Bigha | 20 Katha (400 Dhoor) | 27,225 Sq.Ft | 62.50 Decimal |
| 1 Decimal (Dismil) | Universal Standard | 435.60 Sq.Ft | 1.00 Decimal |
| 1 Acre | 32 Katha (approx.) / 1.6 Bigha | 43,560 Sq.Ft | 100 Decimal |
| 1 Hectare | 2.471 Acres | 1,07,639 Sq.Ft | 247.10 Decimal |
Understanding "Laggi" (Haath) System in Bihar Land Measurement
Why does the size of 1 Katha change when you travel from Patna to Muzaffarpur, Chhapra, or Ranchi? The reason lies in the historical Laggi (measuring rod) system. One standard Haath equals 18 inches (1.5 feet):
- 1 Dhoor = (Laggi in Feet) × (Laggi in Feet). For example, if a district uses a 5.5 Haath Laggi, its length in feet is 5.5 × 1.5 = 8.25 feet. Squaring this gives 8.25 × 8.25 = 68.0625 Sq.Ft per Dhoor.
- 1 Katha = 20 × 1 Dhoor = 20 × 68.0625 = 1,361.25 Sq.Ft.
- Because Decimal (435.6 Sq.Ft) and Acre (43,560 Sq.Ft) never change across districts, Bihar Bhumi and UP Bhulekh portals officially record land mutations (Dakhil-Kharij) in Decimal, Acre, and Hectare.
Frequently Asked Questions (FAQs)
1. How many Square Feet are in 1 Katha in Patna vs Ranchi?
In Patna and nearby districts of Bihar, 1 Katha is strictly 1,361.25 Square Feet (3.125 Decimal). In Ranchi and most parts of Jharkhand, 1 Katha is much smaller, equaling 720 Square Feet (approx. 1.65 Decimal).
2. How do I convert Square Feet into Decimal (Dismil)?
Simply divide the total Square Feet by 435.6. For example, if your plot is 2,178 Sq.Ft, dividing 2,178 by 435.6 gives exactly 5 Decimal.
3. What is the difference between Katha and Biswa?
Both represent 1/20th of a Bigha. In Bihar, Jharkhand, West Bengal, and Assam, the unit is called Katha, whereas in Uttar Pradesh, Uttarakhand, Haryana, and Rajasthan, the equivalent unit is called Biswa.