Lawn Mowers Sizes Explained

In depth

Lawn mowers are often marketed with confusing size designations – ‘12’, ‘18’, ‘24’, ‘30’ – that can leave buyers unsure of what they're actually purchasing. These numbers aren’t simply about the engine power; they represent the cutting width of the mower deck, and understanding this is absolutely crucial to choosing a machine suitable for your garden. The cutting width refers to the distance between the front and rear edges of the mower blade when it rotates. It’s usually expressed in inches, and the number you see on a lawnmower – for example, a ‘30’ inch mower – indicates this width.

The most common lawnmowers available in the UK fall into three primary size categories: narrow (18-24 inch decks), medium (24-30 inch decks), and wide (30+ inch decks). Narrow mowers, typically around 18 or 20 inches, are ideal for smaller lawns – generally under 500 square metres. They’re incredibly manoeuvrable, making them great for navigating tight spaces like borders, around trees, and along pathways. Because of their narrow width, they can also get closer to edges without the risk of scalping the lawn; a key benefit if you're particularly concerned about maintaining a neat finish. However, on larger lawns, you’ll find yourself repeatedly returning to the same area, significantly increasing mowing time.

Moving up to 24 and 30-inch mowers represents a more versatile solution for gardens between 500 and 1000 square metres. These sizes offer a good balance between cutting width – which reduces the number of passes required – and manoeuvrability. A 24-inch mower will still be relatively easy to handle, particularly on slightly uneven ground, while the wider deck will cover more area with each pass. Thirty-inch mowers are suitable for larger gardens up to around 1200 square metres. They’re noticeably heavier than smaller models and require a bit more strength to manoeuvre, but the increased cutting width significantly reduces mowing time on bigger spaces.

A very common mistake amongst first-time lawnmower buyers is opting for a wide mower deck – often a 30 inch or greater – when they have a relatively small garden. The larger cutting area can actually *increase* the amount of time it takes to complete a job, especially if you're not used to operating a larger machine. It’s much more efficient to choose a mower that matches the size of your lawn; attempting to force a wide mower into a compact space will simply result in slower mowing and potential damage to borders or delicate plants. Always prioritise the area you need to cover, rather than being swayed by the perceived benefit of a wider cutting deck.

Before making any purchase, it’s essential to accurately measure your lawn's dimensions. Don’t just estimate; take precise measurements using a measuring tape. Consider the overall length and width of your garden, as well as any obstacles – trees, sheds, patios – that might affect your mowing strategy. A simple way to calculate the area is by multiplying the length by the width. However, remember to account for areas you don't intend to mow, such as flowerbeds or pathways, when determining the appropriate mower size. If you have a particularly oddly shaped lawn, it’s often better to overestimate slightly than underestimate, especially if you plan on regularly maintaining a pristine finish.

Finally, consider the terrain of your garden. A steep slope will necessitate a lighter, more manoeuvrable mower – generally a narrower model – making it easier to control and preventing accidental rolls. Flat, relatively level lawns are suitable for wider mowers, allowing you to cover larger areas quickly. It's worth noting that some lawnmower manufacturers offer models with adjustable deck heights, which can be beneficial if your garden has varying levels of ground. This allows you to raise the deck in low-lying areas and lower it in slightly raised sections, ensuring a consistent cut across your entire lawn.