How long can you use a cot bed mattress?
Short answer: Typically from birth through the cot and toddler-bed years. 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.
- Confirm the cot bed's mattress size before buying, as frames vary.
- Firm, flat, waterproof, with a snug fit.
- Choose foam, spring or fibre for your budget and how much you need to wipe or wash it.
What the guidance says
- Use a firm, flat, waterproof mattress in good condition, with no raised or cushioned edges, that fits the cot or Moses basket with no gaps.
- The Lullaby Trust says your baby's head should sink no more than a few millimetres into the mattress.
- The Lullaby Trust recommends a new mattress for each baby where possible. A second-hand one should have a 100% waterproof cover, no rips, tears or water damage, no sagging, a good fit and a fire-resistant label.
- Mattresses: look for BS 7177:2008+A1:2011, and BS EN 16890:2017+A1:2021 for cot, travel cot and crib mattresses.
Related questions
What is a cot bed mattress?
A firm, flat mattress for a cot bed, usually 140 x 70cm, which carries on into the toddler-bed stage.
Shop at Baby Kingdom
- Obaby Sprung Mattress - 140 x 70cm
- Kidsaw Deluxe Sprung Toddler Cot Bed Mattress
- Tutti Bambini Eco Fibre Cot Bed Mattress (70 x 140 cm)
- Ickle Bubba All Seasons Premium Pocket Sprung Mattress 140 x 70cm
Check each product page for its exact dimensions, mattress size, age and weight limits and safety standards.
More advice
Is a travel cot mattress right for you? Quick quizHow do I choose a cot mattress?Is a sheepskin safe in a cot?Guide to mattress protectors: what to look forWhich baby mattress size do you need?Travel cot mattresses buying guide for UK parentsAll cot and baby mattresses advice →
Sources
- 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.