Get the fit right

Measure over what you'll wear underneath

Overtrousers are designed to fit over another layer, but how much room they allow varies between brands. Measure your waist and hips over the trousers you normally wear underneath, whether that is walking trousers, jeans, thermal leggings or padded work trousers, and compare with the maker's size chart rather than assuming your usual size.

If you wear bulky layers (winter work trousers, knee pads, motorcycle armour), take them with you when trying on, or size up.

Leg length

Overtrousers should cover the top of your boot or welly by a few centimetres when you're standing, so rain runs down the outside of the boot rather than into it. They should stay clear of the ground at the heel. Too short and they ride up above the boot when you bend your knee; too long and they drag in the mud, fray at the heel and catch on crampons or bike chains.

Many makers offer short, regular and long leg lengths. If you're under or over average height, look for those options rather than relying on adjustable cuffs.

The step-up test

Before you remove the tags, try them on over your usual layers and footwear, then:

• Step up high, as if onto a stile or a tall rock. The crotch shouldn't pull tight and the waist shouldn't drag down at the back.
• Squat and kneel. Check the knees aren't straining and the waist stays covered at the back.
• Sit down. The hem should still cover the top of your boots.
• Check the zips open far enough to get your boots through.
• Walk briskly and listen: are they rubbing or rustling annoyingly?

Waist and braces

Most overtrousers have an elasticated waist with a drawcord, which copes with a range of sizes and layers. If you find they slide down when you move (common with heavier fabrics or bulging pockets), consider a pair with braces, or a bib-and-brace style, particularly for work, fishing and farming.

Women's and kids' sizing

Unisex overtrousers are usually cut on men's proportions, which can mean a baggy leg and a tight hip. Women's-specific cuts are worth trying if unisex styles don't fit well. For children, buy by height rather than age, with a little growing room. See our kids & school guide.