Wondering what size sheets fit on a cot? The short answer: most standard Australian cots take a sheet sized around 130 x 70 cm, but the mattress thickness matters just as much as the length and width. Get that wrong and the sheet pops off at the corners, which is both annoying and unsafe.
This guide covers how to measure correctly, how to fit a sheet so it stays put, and what to check before you leave the nursery.
Standard Cot Sheet Sizes in Australia
Australian cot mattresses are most commonly 130 x 70 cm or 132 x 68 cm depending on the brand. Some compact or travel cots run smaller, around 120 x 60 cm. Always check your mattress, not just the cot frame.
The pocket depth on a fitted sheet needs to match your mattress thickness. Most standard cot mattresses sit between 10 cm and 15 cm deep. A sheet with a shallow pocket on a thick mattress will not stay tucked and can bunch under your baby.
- Measure mattress length, width and thickness before buying any sheet.
- Standard AU cot sheet: approximately 130 x 70 cm with a 15 cm pocket depth.
- Compact or travel cot sheet: approximately 120 x 60 cm.
- Bassinet sheet: approximately 75 x 35 cm, though sizes vary between brands.
If your mattress sits between two sizes, always go with the option that wraps fully under each corner without pulling tight. A sheet under tension is more likely to snap loose during the night.
How to Fit a Cot Sheet Properly
A correctly fitted sheet takes less than a minute. Do it in this order and the sheet will lie flat with no gaps at the corners.
- Start at one corner. Push the pocket fully underneath the mattress, not just over the edge.
- Move to the opposite diagonal corner and repeat. This keeps tension even across the sheet.
- Work around to the remaining two corners.
- Run your hand across the sleep surface. It should feel firm and smooth with no loose fabric.
- Check that the sheet is not lifting at any corner before placing your baby down.
If the sheet keeps popping off, it is almost always a sizing issue rather than a fitting issue. The pocket depth is too shallow for your mattress thickness. Measure again and look for a deeper pocket.
What to Check Every Time You Change the Sheet
Safe sleep guidelines recommend a firm, flat, fitted sheet with nothing else in the cot. No pillows, no bumpers, no loose blankets for babies under 12 months. Every time you put a fresh sheet on, run through this quick check.
- All four corners are fully tucked under the mattress.
- The surface is flat with no raised fabric or wrinkles near the head area.
- The sheet has not shifted or bunched after you lift your hands away.
- There is no visible gap between the sheet edge and the mattress side.
It is worth doing this check again after your baby has been in the cot, especially once they start moving around. A sheet that fits fine at bedtime can shift if a baby rolls or kicks during the night.
Fabric Makes a Difference Too
Cotton jersey and bamboo jersey stretch slightly to hug the mattress corners, which makes them easier to keep in place. Woven cotton percale sits flatter and feels cooler, but it needs a well-matched pocket depth to stay put. During winter, a fitted sheet with a little warmth to it can mean your baby stays comfortable without needing extra layers. If you are building out your nursery kit for the colder months, take a look at our winter essentials guide for mum and bub for practical product picks.
Wash your sheets before first use. Most fabrics shrink slightly in the first wash. If a sheet fits perfectly out of the packet, it may be too tight after washing. Factor this in when buying, especially if your mattress is on the thicker side.
How Many Cot Sheets Do You Actually Need?
At minimum, three. One on the cot, one in the wash and one spare for middle-of-the-night changes. If your baby is prone to reflux or nappy leaks, four or five makes the rotation much easier to manage. Having enough clean sheets on hand means you are never caught short at 2 am.
If you are still figuring out what else you need for the nursery, it helps to understand your baby's development alongside your product choices. Our piece on the Wonder Weeks and what to expect is a good starting point for understanding sleep and settling patterns in the early months.
You can browse our full range of baby and nursery products to find fitted sheets, bassinet sheets and everything else you need for a well-set-up sleep space.
