What size lawnmower should I buy?

This, of course, depends partly on the size of your lawn. The general rule of thumb is that the larger your lawn, the larger your lawn mower needs to be.

Larger mowers generally have larger cutting widths, so when reviews mention mower size, this is generally what is meant. It would be unusual to find a huge petrol mower with a large powerful engine and a very narrow cutting width.

Of course, there are more factors involved in this decision than just size. For example, do you need a self-propelled mower? How powerful a mower do you need?  What size collector do you need?   However, regarding lawn size alone, here is a rough guide to what you may need. 

Lawn size (in m2)   

Mower size recommended (cw in cm)

0-100    Under 30
0-250  30-34
100-250     35-39
100-500    40-44 P
250-750 40-44 SP
250-1000      45-49 P
500-1500      45-49 SP
750-2000 50-54cm SP (E -175 cc)
1000-3000        50-54cm SP (E + 175 cc)
1000-3000       55-59cm SP

Key: cm = centimetres cw = Cutting width.P = Push. SP = Self Propelled.

M2 = Square Metres. E = Engine  + = More than.  - = Less than.

cc= cubic centimetres (displacement) 

N.B. You can, of course, buy a larger lawnmower than is recommended for your size of lawn, and people do this in order to cover the lawn faster. However, it is worth considering small spaces, tight corners or awkward spots you have in your garden that may be negotiated more easily with a smaller mower.