Square Footage Calculator

Written byOleh Soloninupdated 5 October 2026

Shape

Length or base

Width or height

Input units

Result

Square metres17.5
Square feet188.37
Square yards20.93
Hectares0.00175
How it was calculated
5 × 3.5 = 17.5 square metres 17.5 ÷ 0.09290304 = 188.37 square feet a hectare is 10,000 m² and an acre 4,046.8564224 m²: 0.00175 ha and 0.00432 acres
Acres0.00432
In the units entered17.5

Metres in, feet out, or the other way round

Area of a rectangle, triangle or circle given straight away in square metres, square feet, square yards, hectares and acres.

A 5 × 3.5 m room is 17.5 m², which is 188.37 square feet, 20.93 square yards and 0.00175 hectares. The conversion is exact: a square foot is precisely 0.09290304 m² and an acre precisely 4,046.8564224 m².

The calculator handles three shapes — rectangle, triangle and circle — and works both ways. If a listing is written in feet, enter feet: 20 × 30 feet is 55.742 m².

How to use

Pick the shape: rectangle, triangle or circle.
Enter the dimensions and the unit they are written in, metres or feet.
Read the area in square metres, square feet, square yards, acres and hectares.

One area in five units

Every row is a separate run of this calculator.

Every value was produced by the calculator on this page.
What is measured	Area	m²	sq ft	sq yd	acres	hectares
Room 5 × 3.5 m	17.5	17.5 m²	188.37	20.93	0.00432	0.00175
Plot 20 × 30 ft	600	55.742 m²	600	66.67	0.01377	0.00557
Circle, radius 5 m	78.54	78.54 m²	845.4	93.93	0.01941	0.00785
Triangle 10 × 6 m	30	30 m²	322.92	35.88	0.00741	0.003

The exact factors

The international foot has been exactly 0.3048 metres since 1959, so a square foot is exactly 0.09290304 m². A square yard is nine square feet, 0.83612736 m², and an acre is 4,840 square yards, 4,046.8564224 m².

All of those factors are exact rather than rounded, and the calculator uses them as they are. That is why 600 square feet comes out as 55.742 m² and not "about 56".

Acres, hectares and what they mean

A hectare is 10,000 m²; an acre is 4,046.86 m², so a hectare is nearly two and a half acres. A plot of 20 × 30 feet, or 55.742 m², is 0.0138 acres.

For rooms the useful unit stays the square metre or the square foot: 17.5 m² is 188.37 sq ft, and in acres it would read 0.00432, which tells nobody anything.

What this calculator shows

Area in square metres and square feet
Square yards, hectares and acres for land
The value in whichever unit you entered

What to keep in mind

A square foot is exactly 0.09290304 m² under the 1959 international agreement.
A hectare is exactly 10,000 m²; an acre is 4,046.86 m².

FAQs

How do I convert square feet to square metres?

Multiply by 0.09290304 — an exact factor, because a foot is exactly 0.3048 m. So 600 square feet is 55.742 m².

How many square feet in a 5 × 3.5 metre room?

188.37: the 17.5 m² divided by 0.09290304. In yards that is 20.93 square yards.

How big is a hectare?

10,000 m², or 107,639 square feet. A 17.5 m² room is 0.00175 hectares — which is why rooms are not measured that way.

How does an acre compare with a hectare?

An acre is 4,046.8564224 m² and a hectare 10,000 m², so one acre is 0.4047 hectares and a hectare is 2.471 acres.

How do I get the area of a circle?

π times the radius squared: a circle of radius 5 m is 78.54 m², or 845.4 square feet. The calculator has a shape for it.

How do I measure a triangular plot?

Base times height divided by two: 10 × 6 ÷ 2 = 30 m². If you only know the three sides, use Heron's formula — this page needs a base and a height.

Worked example

A 5 × 3.5 metre room

Input: rectangle, 5 × 3.5 m

Output: 17.5 m², 188.37 sq ft, 20.93 sq yd

Note: That is 0.00432 acres and 0.00175 hectares.

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