Why is my mattress smaller than my bed frame?

The question to ask here is why is my bed frame bigger than the standard size mattresses.

Most bed frames apart from Ikea bed frames are made larger than standard Australian size. This is because most bed frames are imported and made to fit the requirements of other countries and importers merely adjust certain arts of the bed frame instead of all parts to accommodate for the Australian market which is much smaller.  There are also other reasons listed below including to allow for sheets and for your hand to go on the side of the bed frame to be able to lift the mattress.

PLEASE MEASURE THE INTERNAL SIZE OF YOUR BED FRAME. You will find it is larger than the standard specified mattress size. 

BED FRAMES ARE DESIGNED TO BE LARGER THAN YOUR MATTRESS. THIS IS NORMAL. THIS IS NOT A FAULT OF THE BED FRAME OR THE MATTRESS.

IF YOU HAD AN OLD MATTRESS ON A BED FRAME AND IT FIT BETTER THIS IS BECAUSE THE MATTRESS EXPANDED OVER TIME.

Most bed frames are made bigger than the mattress size to accommodate thick doonas and sheets, to enable you to put your hand on the side to lift up the mattress and to allow the expansion of the mattress as time goes on. Bed frames can be anywhere from 2-5cm bigger on each side depending on the country of origin of the bed frame. 

American origin designed bed frames are very wide and often require a base to be set into the bed frame as part of the design.

 

These are the standard mattress sizes

Single 92x188cm

King Single 107x203cm

Double 137x188cm

Queen 153x203cm

King 183x203cm

 

Not every single mattress is going to be this exact size as they are hand made and different designed mattresses can vary by 1-2%.

The most important factor is the person measuring the mattress, you must measure using a metal tape measure and have the mattress lied down flat on the ground. Mattress size is taken from the tape edge of the mattress, not the narrowest part of the mattress.  Basically, most people measure a mattress incorrectly and then assume it is the fault of the mattress. Mattress foam boxes and metal edge frame are made in exact batches, it would be impossible to make a mattress 5cm longer or shorter unless on purpose. 

For example steel edge mattresses measure smaller than box foam edge mattresses as the spring system on a steel edge support mattress will expand over time. A box foam edge mattress will generally keep it’s shape as the box system has been glued in. In a foam mattress, they are generally made up to an inch smaller to allow for the expansion of the mattress once you have started to use it, the foam mattress will grow in size.

 

Measuring a mattress that is upright means the mattress height has reduced by 3-4cm as the spring inside the mattress structure moves with gravity and the mattress will get shorter. 

 

Depending on the internal structure of the mattress, some mattresses are made 1-2cm small on each side to allow for the expansion of the mattress with you.