Ultimate Cot Mattress Size Guide

Choosing the right cot mattress size ensures your baby’s safety, comfort, and a snug fit in their cot. A well‑fitting mattress helps reduce gaps where little limbs could get trapped, supports healthy spinal development, and promotes better sleep. In this guide, we break down standard Australian dimensions, measurement tips, thickness recommendations, and FAQs to help you find the perfect cot mattress. Browse our range of cot mattresses.

Why Cot Mattress Size Matters

A correctly sized cot mattress is crucial for:

• Safety: A mattress with gaps wider than 20 mm from the cot edge can pose entrapment risks and increase SIDS warnings.

• Comfort: A flat, firm surface encourages proper spinal alignment and prevents babies from rolling into unsafe positions.

• Compatibility: Many cots come in standard and compact dimensions, so checking the cot mattress size before purchase avoids costly returns.

Standard Cot Mattress Sizes in Australia

Most Australian cot mattresses fall into two categories. Exact dimensions can vary by brand, so always check manufacturer guidelines.

Standard Size Cots

Standard cot mattresses (130 × 69 cm) suit most full‑size cots and accommodate children from birth up to around 3 years. Popular models include convertibles that evolve into toddler beds.

Compact Size Cots

Compact or mini cot mattresses (120 × 60 cm) are perfect for nurseries with limited space, travel cots and for parents who prefer a smaller sleeping area during the first 6 months.

How to Measure Your Cot Mattress

1. Empty the cot: Remove any existing mattress and bedding.

2. Measure internal dimensions: Use a tape measure to record the length and width at the top of the mattress base.

3. Allow for snug fit: Aim for a mattress no more than 20 mm away from any cot side. Too much gap undermines safety.

4. Check thickness: Measure depth—ideal is around 100 mm, maximum 150 mm to maintain correct sheet fitting and firmness.

Cot Mattress Thickness Guide

Depth affects both support and breathability. Australian standard AS/NZS 8811.1:2013 recommends:

• Minimum thickness: 75 mm for adequate padding

• Ideal thickness: 100 mm for balance of comfort and safety

• Maximum thickness: 150 mm to prevent soft‑landing hazards

Always choose a firm mattress that resists indentation under baby’s head.

Choosing the Right Mattress for Your Cot

When shopping for a cot mattress:

• Fit first: Confirm cot mattress size matches your cot model.

• Material matters: High‑density foam and natural latex are firm yet breathable.

• Firmness: A firm sleeping surface reduces SIDS risk—avoid overly plush options.

• Breathability: Cotton covers and open‑cell cores help regulate temperature in 20–22 °C rooms.

Frequently Asked Questions

Can I use a slightly smaller/larger mattress?

Many parents wonder, “can you reuse a cot mattress from a previous child or swap in one that’s slightly different?” While reusing a mattress can be economical, only do so if it matches your cot’s recommended dimensions within 20 mm, shows no signs of wear, and still meets current safety standards.

What’s the best mattress type for newborns?

Firm, flat surfaces made from high‑density foam or natural latex are ideal. Although are all cot mattresses the same size? In Australia, most follow the standard or compact sizes above, but material and construction can vary significantly between brands.

Do cot mattresses expire?

Mattresses don’t have a legal “expiry,” but manufacturers often recommend replacement every 5 years or sooner if you notice sagging, tears or hygiene concerns.

Final Tips for Buying the Right Cot Mattress

• Prioritise fit over price: A snug, firm mattress is worth the investment.

• Verify specs: Always check both length/width and depth before ordering online.

• Safety certifications: Look for compliance with AS/NZS 8811.1:2013.
  
  

With the right cot mattress size, material and fit, your little one will enjoy safer, more restful sleep—and so will you.