How this calculation works
A planting grid estimates intended positions before establishment. A stand count measures plants actually observed afterward. Gaps and uneven emergence can make those two populations different even when the nominal row spacing is unchanged.
Pooled plants/ha = total counted plants/Σ(row length × represented row spacing) × 10000A worked example
Sample A counts fifty plants in five metres of half-metre rows, representing 2.5 m². Sample B counts eighty in ten metres, representing five m². Pooling gives 130 plants over 7.5 m², or about 173333 plants/ha. Averaging the sample densities of twenty and sixteen would instead give eighteen plants/m², which overweights the shorter sample.
Good to know
Observed one-row-strip density estimate only; no automatic field sampling, statistical interval, yield forecast or target population recommendation. A large projected field total can still be uncertain if samples are few or biased. Preserve the sample table and actual field observations alongside the pooled number.
Reference: UMN Extension — observed stand counts (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.
What the model answers
A planting grid estimates intended positions before establishment. A stand count measures plants actually observed afterward. Gaps and uneven emergence can make those two populations different even when the nominal row spacing is unchanged.
This page treats each counted row segment as representing its row spacing times measured length. It pools total plants over total sampled area so unequal sample lengths are weighted appropriately.
The Rectangular planting grid calculator counts intended positions from spacing and boundaries. This stand-count page measures observed density and should not silently replace a planned grid with a field survival assumption.
Measure and enter consistently
Count whole plants using a consistent field definition, and enter the row length actually examined. Row spacing is the width represented by that one row, not the total width of several counted rows unless the length/count representation is adjusted consistently.
Sample labels are identifiers, not locations or a sampling plan. The calculator does not select representative areas, distinguish healthy from noncontributing plants or identify weeds from images. Those choices determine what the counts mean.
Interpret the result
Per-sample densities expose variation that the pooled estimate can hide. An unweighted average of those densities would give a tiny segment the same influence as a large segment, which is not the method used here.
The projected total assumes the sampled density represents the entered field area. No confidence interval or yield model is inferred from a set of possibly nonrandom row observations. It is not a replanting recommendation.
Work through the numbers
Sample A counts fifty plants in five metres of half-metre rows, representing 2.5 m². Sample B counts eighty in ten metres, representing five m².
Pooling gives 130 plants over 7.5 m², or about 173333 plants/ha. Averaging the sample densities of twenty and sixteen would instead give eighteen plants/m², which overweights the shorter sample.
Where this model stops
Observed one-row-strip density estimate only; no automatic field sampling, statistical interval, yield forecast or target population recommendation.
A large projected field total can still be uncertain if samples are few or biased. Preserve the sample table and actual field observations alongside the pooled number.
A few questions, answered
Why not average the sample densities equally?
Unequal sample areas need area weighting. Total count divided by total area gives that pooled estimate.
Is this the same as planting spacing?
No. This estimates observed established plants, while a planting grid counts intended positions.