1. Start with who's sleeping in the bed

The right mattress size comes down to who's using it and how they sleep. Solo sleepers can be comfortable in a single, king single or double, while couples generally need at least a queen to sleep without disturbing each other. If you share your bed with kids or pets, or one of you tosses and turns, a king or super king gives everyone room to settle.

2. Measure your room before you fall in love with a bed

A bigger bed isn't always better if it leaves you squeezing past the wardrobe. As a rule of thumb, allow about 60cm of clear space on each side and at the foot of the bed. Don't forget doors, windows, wardrobes and bedside tables. Our interactive size guide lets you enter your room dimensions and see how each size fits before you buy.

3. Consider height as well as width

Width gets all the attention, but length matters too. Single and double mattresses are 1880mm long, while long single, king single, queen, king and super king sizes are 2030mm long. If you're over 180cm tall, or shopping for a teen who's still growing, choose a longer size so your feet aren't hanging off the end.

4. Remember your base and bed frame

Your mattress size sets the foundation, but your full bed setup can take up more space. Bed bases match standard mattress sizes, while bed frames, especially upholstered designs with headboards, can add extra width and length. Use the size guide to get a feel for the overall footprint, then check each product's exact dimensions.

5. Think about the future

Buying a mattress is a long-term investment, so think about where life is heading. Is your child about to hit a growth spurt? Are you moving in with a partner? Planning a bigger bedroom? Choosing a size that suits your needs for years to come means you won't be shopping again too soon.

Mattress size comparison guide

Here are the seven most common Australian bed sizes with mattress dimensions in both metric and imperial.