Lawn Care
Lawn Area Calculator: Measure Your Lawn Size
Calculate your lawn area in square metres and square feet before buying turf, grass seed, or fertiliser.
Estimated lawn area
Lawn area results
Measured area is 1,000.00 sq ft before subtracting non-lawn areas. Use this value for grass seed, fertilizer, soil, or topdressing estimates.
Why lawn area matters
Most lawn products are applied by area. Grass seed, fertilizer, compost, topsoil, and soil amendments often use rates per 1,000 square feet. Measuring lawn area first helps prevent underbuying, overbuying, and uneven application.
Common lawn area formulas
| Shape | Formula | Example |
|---|---|---|
| Rectangle | length x width | 40 ft x 25 ft = 1,000 sq ft |
| Square | side x side | 30 ft x 30 ft = 900 sq ft |
| Circle | pi x radius squared | 36 ft diameter = about 1,018 sq ft |
| Irregular lawn | split into smaller shapes | add each section, then subtract non-lawn areas |
Example
A backyard is 60 ft by 40 ft, but a patio covers 300 sq ft. Gross area is 2,400 sq ft. Subtract 300 sq ft, and the lawn area is 2,100 sq ft. Use 2.1 units of 1,000 sq ft when estimating seed or fertilizer.
What to do next
- Use the Lawn Seed Calculator to estimate seed from your lawn area.
- Use the Fertilizer NPK Calculator for nitrogen-based fertilizer math.
- Use the Soil Calculator for lawn topdressing or shallow fill.
FAQ
Lawn area calculator FAQ
How do I calculate lawn square footage?
For a rectangle, multiply length by width. For a circle, use pi times radius squared. For irregular lawns, split the area into smaller shapes and add them together.
Should I subtract patios and garden beds?
Yes. Subtract areas that will not receive seed, fertilizer, soil, or other lawn products.
Why does the result show 1,000 sq ft units?
Many seed and fertilizer rates are listed per 1,000 square feet, so this number makes the next calculation easier.
How many square feet are in an acre?
One acre equals 43,560 square feet.
Can I use metres?
Yes. Select metres / square metres and the calculator will convert the result to square feet and square metres.