A firm, wrinkle-free sheet that grips all four corners helps keep your baby’s sleep surface safe and comfortable. Use this quick guide to measure, fit and check your sheet in minutes.
1) Measure before you buy
- Measure the mattress — length × width × thickness (height).
- Match to the closest fitted size. If between sizes, choose the option that fully wraps under the corners without strain.
- See the full sizing table: Cot & Bassinet Sheet Size Guide (AU).
2) Fit steps (60-second routine)
- Start at a corner and pull the pocket fully underneath the mattress.
- Repeat on the opposite corner to create even tension.
- Smooth the surface, then fit the remaining corners.
- Lift test: try to pinch and lift the sheet at the middle. A good fit won’t billow or pop off.
3) Safety checks (do this weekly)
- No slack or bunching anywhere on the sleep surface.
- All corners wrapped under the mattress — elastic not riding up.
- Only a fitted sheet on a firm mattress; no loose bedding or bumpers.
4) Troubleshooting common fit issues
- Corner pops off: re-seat the first two corners on the long side, then refit the others. If it persists, size may be off — check our size guide.
- Wrinkles in the centre: sheet too large; try a smaller size or a deeper pocket with stronger elastic.
- Protector + sheet bunching: if you use two layers, both must be firm-fitting. Consider a 2-in-1 waterproof fitted sheet to reduce layers.
5) Care that preserves fit
- Use a gentle cycle and mild liquid detergent; avoid bleach and fabric softener.
- Line dry where possible; low heat only if your care label allows.
- Full care steps: How to wash waterproof bamboo cot sheets.
Recommended products
Related guides
Trusted resources