How long can you use a cot sheet?
Short answer: Typically from birth. Always go by the age, weight and development limits in the instructions for your model.
Product limits vary, so check the instructions and the product page.
- Match the sheet size to the mattress (for example 120 x 60cm or 140 x 70cm).
- Fitted sheets should sit tight and flat, with no loose fabric.
- Buy at least two or three for night-time changes.
What the guidance says
- The Lullaby Trust says a baby needs just two items in their cot: a firm, flat, waterproof mattress and lightweight bedding.
- If you use sheets and blankets, tuck them in firmly no higher than shoulder height. One blanket doubled over counts as two.
Related questions
What is a cot sheet?
A fitted sheet sized to the cot mattress.
Shop at Baby Kingdom
- Cot Fitted Sheets 2pk
- Muslin Fitted Sheet 140cm x 70cm - Ocean Stripe
- Essentials Cot Bed Fitted Sheets 2pk
- Cot Bed Fitted Sheets 2pk
Check each product page for its exact dimensions, mattress size, age and weight limits and safety standards.
More advice
Cot sheets buying guide for UK parentsCan a 5 month old sleep in a sleeping bag?Can I swaddle my baby?Can a 2 month old sleep in a sleeping bag?Guide to swaddles & blankets: what to look forBaby sleeping bags buying guide for UK parentsAll baby bedding and sleeping bags advice →
Sources
- The Lullaby Trust: Safer sleep advice (accessed 2026-10-21)
- The Lullaby Trust: Baby mattresses and bedding (accessed 2026-10-21)
General information only, not medical advice. Always follow your product's instructions. If you are worried about your baby, contact your GP, health visitor or 111. In an emergency, call 999.