How to Fit a Waterproof Cot Mattress Protector: 60 x 120 Guide
By UK Baby Centre | Published: 2026-11-02
Category: How-to Guides
A step-by-step guide to fitting a 60 x 120 waterproof cot mattress protector, with washing tips and a check on whether your cot really needs one.
Quick answer
Lay the protector flat on the mattress before the sheet, smooth out every crease, and tuck the elasticated skirt right under all four corners. Then check that the sheet sits flat on top with no bunching. A 60 x 120 protector should fit snugly, not loosely.
Why fit matters more than fabric choice
A protector that is too loose can ruck up under the sheet, and a protector that is too tight can pull the sheet corners free. Either way, your baby ends up lying on folds rather than a flat surface. The fit is the safety-critical part, not the waterproof layer itself.
Cotton waterproof protectors work by adding a thin, undetectable polyurethane layer behind soft cotton. That layer keeps moisture out, but it also means the protector does not stretch like a plain sheet. Fit it smooth and flat the first time, and it stays that way through the night.
When a cot protector is worth it, and when it is not
You do not strictly need a mattress protector for a cot, but it saves you from replacing a mattress after every leak, spill or sick episode. If your cot mattress has a wipe-clean cover and your baby rarely leaks, you can manage without one. If you are potty training, dealing with reflux, or sharing a cot between children, a protector pays for itself quickly.
The trade-off is an extra layer between your baby and the mattress. Choose a breathable cotton protector rather than a plastic sheet if you are worried about clamminess, and always follow the cot mattress manufacturer's guidance on what can be placed on top.
Sizing check before you buy
Cot sizes vary, so measure your mattress before ordering a 60 x 120 waterproof mattress protector. The Hippychick protector is made for a 60 x 120 cot, and a protector sized for a larger mattress will wrinkle under a smaller sheet. If your cot is an unusual size, check the product listing rather than assuming a standard fit.
How to fit a 60 x 120 waterproof cot mattress protector
- Measure and check the mattress: Measure the cot mattress before fitting. It should be 60 x 120 cm for a protector sold in that size. If the mattress is thicker than usual, check that the elasticated skirt will reach under it. A protector that only just stretches over the corners will ping off during the night.
- Lay the protector flat, cotton side up: Unfold the protector and place it on the mattress with the soft cotton side facing up and the waterproof layer underneath. Smooth it from the centre outwards with the flat of your hand. Check for creases near the head end, where your baby's face will rest.
- Tuck the elasticated skirt under all four corners: Pull the skirt down over one corner at a time, working diagonally so the protector stays centred. Run your hand around the edge to confirm the elastic is fully under the mattress, not caught on top. If one corner keeps slipping, the protector is probably the wrong size for the mattress.
- Fit the sheet over the top and smooth it down: Put your usual cot sheet on over the protector and smooth out any wrinkles. The sheet should sit flat, with no ridge where the protector's elastic ends. A visible ridge under the sheet means the protector is not tucked far enough under.
- Do a final press test: Press down on each corner and the centre of the mattress. You should feel a flat surface with no loose fabric. If the protector moves independently of the mattress, refit it before putting your baby down. Refit after every wash, as cotton protectors can shrink slightly the first time.
- Wash and refit without guesswork: Follow the care label on your protector. As a general rule for cotton waterproof cot protectors, wash at a moderate temperature and avoid fabric softener, which can reduce absorbency. Tumble dry on low only if the label allows, and refit once fully dry. Buy a second protector so you can wash one while the other is on the cot.
Product facts
- Hippychick Waterproof Fitted Mattress Protector (Cot, 60 x 120) - Cotton: Hippychick Cotton Mattress Protectors are 100% waterproof, with a soft cotton surface over an undetectable polyurethane layer. You get leak protection without the sweaty feel of a plastic sheet, so it can stay on the mattress every night.
Hippychick Waterproof Fitted Mattress Protector (Cot, 60 x 120) - Cotton
