Grass Seed Calculator


Our online grass seed calculator will help you calculate how much seed you will require for your garden lawn or amenity project.

We have split this into sowing, which is for new gardens and overseeding which can be used to rejuvenate a tired lawn. Enter the length and width of the area you wish to seed.

Calculating Seed and Turf Quantities

It is far easier to measure areas in metres, but for customers who are more comfortable with feet and inches here are some examples to help you work it out:-


Area measurements: 18.750m x 22.430m
Simply multiply the two figures together using a calculator and the result is 420 square metres (m2)

If you intended sowing rate is 50grammes/m2 then multiply the area (420m2) by the sowing rate (0.050). The result is 21kgs of seed.

Alternatively, if you have the equipment to sow more accurately then the reduced rate (of 35grammes/m2) can be utilised. As before multiply the area (420m2) , but this time by 0.035. The result is 14.7kgs of seed.

Wild flower/grass meadow mixtures have much lower sowing rates, i.e. around 5gms/m2.
The calculation is 420m2 x 0.005
The result is 2.1kg of seed

With turf , it is even simpler as each roll of turf covers an area of 1m2, so the calculation is 420 x 1 = 420m2 of turf.


Taking the same area as above but measured in feet and inches we need to do a few more calculations initially.
a) To convert 61’ – 6” to metres multiply 61.5 x 0.305 and the result is 18.755 metres. You will notice that we needed to convert the 61feet and 6 inches into a metric equivalent , i.e. 61.5 feet

To convert the other dimension 73’-6” we do exactly the same again, i.e. 73.5 x 0.305
= 22.420 metres

This gives us an area of 420m2

Return to the METRIC workings out and proceed as though you had started out in metres.