The real area of an irregular plot, from its four sides
Type the four side lengths in feet or metres and get the area in square feet, square metres and cents. Add one diagonal and the area is exact. Without it you get the largest area those sides can hold, and either way you see how far a length-times-width quote overstates it.
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- In square metres
- 197.30 sq.m
- In cents
- 4.875 cents
- Length times width
- 2,187.5 sq.ft (3.01% above)
- Largest possible for these sides
- 2,175.0 sq.ft
Freeevery run
What we need
One thing at a time. Fill it in and press Run.
The answer
Worked out from the figures you gave, with the rule behind each number.
Nothing run yet. The answer appears here with everything this mini adds:
- The area in square feet, square metres and cents together
- The exact area when you add one diagonal, the largest possible without it
- How far the naive length-times-width figure overstates an irregular plot
- Whether the plot counts as a corner plot from the sides you mark
Plot area, briefly
An irregular plot is one whose four sides are not two equal pairs at right angles, so multiplying an average length by an average width gives more area than the land really holds.
- Four sides alone
- An upper limit
Four lengths can close into many shapes. The answer is the largest area they can enclose, and the real plot is that or smaller.
- Add one diagonal
- Exact area
A diagonal splits the plot into two triangles whose areas are fixed by their sides, so the shape and the area are settled.
- Units
- sq.ft, sq.m, cents
All three together. One cent is 40.4686 square metres, about 435.6 square feet.
How to work out the area of an irregular plot
- 1
Measure the four sides
Go round the plot in order, starting with the front as side A. Feet or metres, whichever your tape reads.
- 2
Measure one diagonal
From the corner where side D meets side A to the corner where side B meets side C. It is optional, and it makes the area exact.
- 3
Mark the road sides and run
Tick the sides that face a road to see whether it counts as a corner plot, then press Run.
When it helps with land
Checking a quoted extent
A seller who multiplies average length by average width quotes more land than an irregular plot holds. The answer shows the gap.
Before paying by the square foot
When the price is per square foot or per cent, the area decides the cheque. Measure the diagonal and pay for the land that is there.
Planning a building
Setbacks, floor space and open space are all worked from the plot area and its road sides, so start from the right figure.
This is the area of the lengths you typed, not the extent in the land records. Compare it with the extent on the patta and the survey sketch (FMB), and have a licensed surveyor measure before you register.
Questions people ask
How do I calculate the area of an irregular plot?
Measure the four sides going round the plot and one diagonal, type them in above in feet or metres, and press Run. With the diagonal the area is exact; with the four sides alone you get the largest area they can enclose.
Why is the area less than length times width?
Because the plot is not a rectangle. Four sides that differ cannot enclose as much as a rectangle with the same average sides, and the difference is what a length-times-width quote adds on.
Do I need the diagonal?
For the exact area, yes. Without it the answer is the largest area the four sides can enclose, and the real plot can only be that or smaller (a plot that leans has less). Measure one diagonal, from the corner where side D meets side A to the corner where side B meets side C.
Can I enter the sides in feet?
Yes. Pick feet or metres; the conversion is done for you, and the area comes back in square feet, square metres and cents.
How many square feet is one cent?
One cent is one hundredth of an acre: 40.4686 square metres, or about 435.6 square feet.
It says my sides cannot close into a plot.
One side is longer than the other three together, or the diagonal does not fit the sides it joins. Re-check the measurements, especially which corner the diagonal runs between.
Is this the extent in the land records?
No. It is the area of the measurements you typed. The recorded extent is in the patta and the survey sketch, and the two should agree closely.
Is this free?
Yes.