How long can you use a cot mattress?

Product limits vary, so check the instructions and the product page.

• Measure the inside of the cot. The mattress should fit with no gaps.
• Choose firm, flat and waterproof. Your baby's head should sink no more than a few millimetres.
• Check for a fire-resistant label and the relevant British Standard.

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 mattress?

A firm, flat mattress for a standard cot, usually 120 x 60cm.

Shop at Baby Kingdom

Browse cot mattresses 120 x 60

• Obaby Pocket Sprung Mattress - 120 x 60cm
• Obaby Foam Cot Mattress 120 x 60 cm
• Tutti Bambini Sprung Cot/Cot Bed Mattress
• Tutti Bambini Eco Fibre Cot Mattress (60 x 120 cm)

Check each product page for its exact dimensions, mattress size, age and weight limits and safety standards.

More 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.