Grass seed calculator

How do I calculate how much grass seed I need?

Whether you’re purchasing lawn grass seed to start that perfectly manicured garden you’ve always dreamed of, paddock grass seed to keep the ponies happy, or you’re buying the best lawn seed for a shady patch, you’ll need to know exactly the right quantity of seed needed.

The amount of grass seed required is not just down to the area that needs to be covered. Density, growth rate and whether you are starting from a clean seed bed or you need grass seed to repair and rejuvenate a space, all define how much seed should be used.

For minor repairs to a lawn, try not to sow the seed too densely or this can result in tufts and an uneven patchy looking lawn. 

If you are looking to create or spruce up a high traffic area such as a grass pathway, sports pitch or hard wearing lawn, a tough grass seed with a higher grass seed sowing rate will serve you best. Our grass seed calculator will take into account whether ryegrass (which will provide the hardiness) will be incorporated into the seed mix and account appropriately.

If you want to create a grassed area that will also benefit the local wildlife or mirror the countryside, why not go for a 80/20 wildflower seed mixture instead? The perfect blend of grass seeds and wildflower seeds. You can use the grass seed calculator to figure out how much wildflower seed mix you’d need too!

How much grass seed is enough?

A good quality grass seed may cost more, but a cheap grass seed will require twice the amount and the results may well be very disappointing if you are after a lush lawn. On the other hand, a fast growing economy grass seed is perfect for larger, general use grassed areas that need to be covered quickly.

Another factor to take into account when ordering grass seed is overestimation. It is a good idea to allow for 30% extra seed. 10% of this will allow for any discrepancies in measurements (we’re only human after all!). Another 10% will allow for unwittingly ‘feeding the birds’, and a further 10% can be kept for future repairs to lawns (sports pitch for the grandchildren, anyone?).

In any case, the Boston Seeds Grass Seed Calculator makes it easy to find out exactly how much grass seed is needed to grow the perfect lawn. Simply enter the dimensions of the area you want to cover with grass seed, choose the type of seed and our tool will do the work for you. Suitable for use on square, circular, and triangular shaped lawns. Have a number of lawns you’d like to seed? No sweat, just add the different sizes and the calculator will provide a total figure. Voila!

1. Area

  • Square shape
  • Circle shape
  • Elipse shape
  • Triangle shape

    2. Seed Type



    3. Requirement

    Please enter details of your area and seed type to calculate