How this calculation works
Normalize each supplied entry before subtracting a shared reference. Show signed differences, the largest absolute difference and the rows outside your entered threshold. The reference is a chosen comparison base, not a determination of the correct legal extent.
Difference = normalized comparison − reference; within tolerance when |difference| × 100 ≤ reference × entered %A worked example
Against 1,200 sq ft, entries of 1,190 sq ft, 111.483648 m² and 1,210 sq ft have differences −10, 0 and +10 sq ft. All are inside an entered 1% threshold of 12 sq ft.
Good to know
An entered-measurement or geometry model. Display rounding and omitted site constraints can change a real result. No survey certification, title, permission, construction or system design is established.
Reference: NIST: exact international-foot and acre factors (opens in a new tab) ↗
Check the land-unit definitions and sources
The standard factors use the international foot and an acre of 43,560 sq ft. Cent means 1/100 acre; gunta means 1/40 acre; the selected Chennai ground means 2,400 sq ft.
The Assam report defines bigha as 14,400 sq ft, katha as 2,880 sq ft and lecha as 144 sq ft. The cited West Bengal court order mentions a 720-sq-ft katha convention. These are explicit presets, not an automatic definition for every record or every place using the same name. Match your record to the stated convention, or use its verified custom factor.
- NIST: exact international-foot and acre factors (opens in a new tab) ↗
- API Setu MDDS: acre/cent and acre/gunta relationships (opens in a new tab) ↗
- Greater Chennai Corporation: one ground is 2,400 sq ft (opens in a new tab) ↗
- Government of Assam AIRBMP framework: section 7.2, page 28 (bigha, katha and lecha) (opens in a new tab) ↗
- Supreme Court order, 7 May 2025: paragraph 2, page 2 (West Bengal katha) (opens in a new tab) ↗
The acre relationships are converted using exact base factors. Rounded or unrelated regional values in a reference table are not substituted for these definitions.
Choose a comparison base without declaring it correct
A reference of 1,200 sq ft gives a common denominator for comparison. It does not establish which deed, plan or measurement is authoritative. The tool reports arithmetic differences from that chosen base, leaving any record or survey decision outside the calculation.
The example’s 111.483648 m² equals exactly 1,200 sq ft under the stated international-foot factor. Comparing the raw numbers 111.483648 and 1,200 without normalizing units would invent a large discrepancy where none exists.
The India land area converter can handle an unfamiliar quantity first. Regional names without a verified definition are not guessed in this comparison table; use the actual supported unit or a separately checked local conversion.
Keep both sign and threshold visible
At an entered 1% tolerance, the example reference produces an absolute threshold of 12 sq ft. The 1,190 and 1,210 sq ft entries differ by −10 and +10 sq ft respectively, and both are within that supplied threshold. Equality with the threshold is also included.
The largest absolute difference identifies the magnitude of a mismatch but not its direction. Read the table’s signed difference for each row. A positive entry is larger than the reference; a negative one is smaller. Opposite signs do not cancel into agreement.
Changing the reference changes the percentage denominator. A ten-square-foot difference is one percent of 1,000 sq ft but half a percent of 2,000 sq ft. Your entered threshold is not promoted into an official survey accuracy or legal significance rule.
A few questions, answered
Does “within tolerance” prove the records agree legally?
No. It means only that the unrounded arithmetic difference satisfies the threshold you supplied.
Why must the reference area be positive?
Percentage difference divides by the reference. Zero would make that comparison undefined.
Can I enter a bigha or katha code?
No automatic regional factor is assigned. Convert using a verified local definition first, then enter a supported area unit.