Decimal to Square Feet: 435.6 Exactly, and What the Roundings Cost
One decimal (dismil, satak) is 435.6 ft², 48.4 gaj and 40.4686 m², 1/100 acre exactly. Same area as a cent; 0.605 Kolkata katha. What 400 and 436 do to a plot.
Decimal to Square Feet — 435.6 exactly, and what the roundings cost
One decimal (dismil, satak) is 435.6 ft², 48.4 gaj and 40.468564224 m²: one hundredth of an acre, with nothing rounded in the chain. It is the unit the Bengal, Bihar, Jharkhand and Odisha records are kept in, the same area the south calls a cent, and 0.605 of a Kolkata katha.
Land in West Bengal, Bihar, Jharkhand, Odisha and Bangladesh is quoted in decimal, spelt dismil in the Bihar glossary and satak in Bengali, and the conversion is one multiplication: 1 decimal = 435.6 ft², so 5 decimal is 2,178 ft² and 202.34 m². The figure is exact because it is built from two definitions and nothing else: an acre is 43,560 ft², and a decimal is one hundredth of it. There is no West Bengal decimal or Bihar decimal that differs from the Odisha one; the unit is defined by the acre, and the acre is the same everywhere.
What goes wrong is the substitutes. Converters print 436, 400 or even 40 m² for a decimal, and each of those moves a plot by a known amount that this page prints beside the exact figure. The other thing that goes wrong is the ladder above it: a katha and a bigha are not fixed fractions of an acre, so “33 decimal to the bigha” is a rounding of 33.06, and the 25 ft² it drops is real land. This page converts the exact unit, shows what each substitute would do, and writes your area the way an acre‑decimal record carries it.
| Decimal | — |
|---|---|
| Square feet | — |
| Square metres | — |
| Gaj (square yards) | — |
| Cent (same area) | — |
| Acre · hectare | — |
| Katha, Bengal 720 ft² | — |
| Bigha, Bengal 14,400 ft² | — |
| As an acre‑decimal record writes it | — |
| As a square plot | — |
| If a rounded decimal were used | — |
| 2 · 3 · 5 · 10 · 33 decimal | — |
A decimal is one hundredth of an acre, and that is the whole definition. The acre is 43,560 ft² by definition, so a decimal is 435.6 ft², which is 48.4 square yards, or gaj, and 40.468564224 m² on the international foot. The Bihar Revenue Glossary gives the unit under its eastern spelling, dismil, as about 435.6 sq ft and one hundredth of an acre, and the acre as 100 decimals; Bangladesh's Ministry of Land table and the Government of India revenue glossary say the same thing of the same fraction. Nobody publishes a rival decimal for any state, because there is nothing to publish: the unit is a fraction, and the thing it is a fraction of does not move. That is what separates it from the katha and the bigha one rung up, and it is why this page prints one number and not a list by region.
It is the same area the south calls a cent. Kerala, Tamil Nadu, Karnataka and Andhra quote land in cent; Bengal, Bihar, Jharkhand, Odisha and Bangladesh quote it in decimal; both are 1/100 acre and both are 435.6 ft². The names differ by region and the number does not, so a “5 cent” plot in Kochi and a “5 decimal” plot in Cuttack are the same 2,178 ft². The cent, and the guntha and ground that sit beside it in southern listings, are on this site's cent page; this page carries the eastern name and the eastern ladder above it and does not repeat that reasoning.
“436 ft²” is harmless, “400 ft²” loses a twelfth, and “40 m²” loses more than it looks. Rounding 435.6 up to 436 adds 0.4 ft² per decimal, 0.09%, and 13 ft² on a 33 decimal plot; that is inside the width of a boundary wall and no deed will notice. Four hundred is 35.6 ft² short per decimal, 8.17%: a 10 decimal plot printed at 4,000 ft² has given away 356 ft², most of a room. Forty square metres is 0.4686 m² short per decimal, 1.16%, and on 33 decimal that is 15.5 m², the floor of a small bedroom. All three circulate on converter sites as if they were the unit, and the two that matter are both short in the same direction, so a buyer pricing off either pays for land that is not being conveyed, or the reverse. The widget prints what each substitute would say for the amount you entered, so the gap is a number and not a percentage.
The katha and the bigha are not fractions of an acre, so the ratios here have tails. On the Bengal measure a katha is 720 ft² and a bigha is 14,400, which makes a decimal 0.605 katha exactly and a katha 1.6529 decimal; a bigha is 33.058 decimal, not 33. The 33 decimal that Kolkata brokers and the Bangladesh ministry table both print for a bigha is 14,374.8 ft², which is 25.2 ft² short of twenty katha, and only the katha ladder closes against the acre (60.5 katha to the acre, exactly). Those two figures are the Bengal ones and no other: Assam puts five katha to the same bigha, Patna's katha is about 1,361 ft², and the Nepal Terai's is 3,645, so the katha and bigha rows on this widget are labelled Bengal and are wrong for anywhere else. The regional ladders, and the regions where no figure can be defended, are on the katha page and the bigha page; nothing about them is re‑derived here.
The record is in acre and decimal, and that is a convention of the record, not a rule this page can cite. The West Bengal record of rights, the Bihar khatian on the state's land records portal, the Jharkhand khatian and the Odisha record of rights on Bhulekh all carry extent as acre and decimal, written as a whole number of acres and a whole or fractional number of decimals; the West Bengal Land Reforms Act, 1955 works in decimals and never uses the word katha. Bangladesh's khatian and mutation records do the same in acre and satak, with the Ministry of Land publishing the 100‑to‑the‑acre figure. Assam is different: the Brahmaputra Valley record runs bigha, katha and lessa, and no Assam record kept in decimal was read for this page, so Assam listings in decimal are market usage as far as this page knows. Each of those is stated from the records themselves and from the glossaries that describe them; no rule prescribing the format was read, and none is cited. The table above writes your area the way such a record would, so a listing in katha can be checked against the khatian without a second conversion.
Exact by definition: 1 acre = 43,560 ft² and 1 ft = 0.3048 m, NIST Handbook 44
(2023), Appendix C, on the international foot in force since 1 January 2023 (85 FR 62698);
1 yd = 3 ft; 1 hectare = 10,000 m². From those, 1 decimal = 43,560/100 = 435.6 ft² =
48.4 yd² = 40.468564224 m²; the arithmetic is exact and no figure on the widget is rounded
before display. The identity gaj = square yard is graded on the gaj page, not here.
That a decimal is 1/100 acre is read from three government documents: the Bihar Revenue Glossary,
Department of Revenue and Land Reforms (approved 13.10.2025), dismil as about 435.6 sq ft and
one hundredth of an acre, and the acre as 100 decimals; the Ministry of Land, Government of Bangladesh,
“Standard Units of Land Measurement in Bangladesh”, which sets the decimal against the acre
at 100 and prints 1 bigha = 33 decimal, a rounding this page corrects; and the Glossary of Revenue Terms,
Department of Land Resources, Ministry of Rural Development, Government of India, whose Kerala chapter
gives the same 1/100 acre under the name cent. These are the citations the cent and katha pages rest on
and they are reused, not re‑sourced.
Katha and bigha at 720 and 14,400 ft² are the Bengal measure of the Manual of Mensuration and
Surveying for Mandals and Patwaris in Assam, Shillong 1900, section 30(b), and the same Bangladesh
ministry table; a government publication, not a statute. Carried and graded on the katha and bigha
pages.
Convention, not rule: that the Bengal, Bihar, Jharkhand and Odisha records of rights, and the
Bangladesh khatian, are kept in acre and decimal is stated from the records and the glossaries that
describe them, and from the West Bengal Land Reforms Act, 1955 working in decimals; no rule prescribing
the format was read. That Assam records run bigha‑katha‑lessa is the 1900 manual; Assam
usage of the decimal was not verified. Several Indian state land‑record hosts refused connections
from outside India while the sibling pages were researched, and nothing on this page was re‑sourced
from them.
Worked example
A Cuttack listing says 5 decimal. How many square feet is that, and how many Kolkata katha?
- A decimal is exactly 1/100 acre: 43,560 ÷ 100 = 435.6 ft². 5 × 435.6 = 2,178 ft².
- 2,178 × 0.09290304 = 202.34 m², and 2,178 ÷ 9 = 242 gaj. It is 0.05 acre, and a khatian would write it as 0 acre 5 decimal.
- On the Bengal ladder a katha is 720 ft², so 2,178 ÷ 720 = 3.025 katha; the same 5 decimal is 5 cent in Kerala. At the 400 ft² rounding the plot would print as 2,000 ft², 178 ft² short.
2,178 ft², 202.34 m², 242 gaj: the same plot a southern listing would call 5 cent, and 3.025 Kolkata katha. The 435.6 is exact from the acre and is the same in every state; only the katha above it changes by region.
12 values on this page were driven in a browser and compared with independently derived figures on 2026-09-09 (2414 values across 203 calculators site-wide).
Questions
How many square feet is 1 decimal?
435.6 ft², exactly one hundredth of an acre (43,560 ft²). That is 48.4 gaj and 40.468564224 m². The figure does not change by state, because the decimal is defined by the acre and nothing else.
Is a decimal the same as a cent?
Yes. Both are 1/100 acre, 435.6 ft². The east (Bengal, Bihar, Jharkhand, Odisha, Bangladesh) says decimal, dismil or satak; the south (Kerala, Tamil Nadu, Karnataka, Andhra) says cent. Only the name differs.
How many decimal in a katha and in a bigha?
On the Bengal measure a katha of 720 ft² is 1.6529 decimal and a bigha of 14,400 ft² is 33.058 decimal, so the 33 decimal usually quoted for a bigha is 25.2 ft² short. Those ratios hold for Kolkata and Bangladesh only; Assam, Bihar and Nepal have other kathas, and the katha and bigha pages carry those.