We recommend mattresses with a score of 70% or more.

Made up of unused, out of the box comfort score (male and female average, 30%), comfort score after eight years of use (30%), stabilisation (15%), sagging (10%), sweat repellent (10%) and usage wear/damage (5%). We also assessed smell out of the box and two weeks after opening for models tested prior to May 2020. These results no longer contribute to the overall score and models tested after May 2020 do not undergo the smell assessment.

We conduct body support tests for both dorsal (on back) and lateral (on side) positions based on male body types only.

We conduct body support tests for both dorsal (on back) and lateral (on side) positions based on female body types only.

We roll a cask-shaped roller over each mattress for 30,000 cycles to simulate approximately eight years' use. Then, based on sleeping assessment in dorsal and lateral positions. Note that this is not an average of the male and female results. It's a separate test that assesses combined male and female usage of the mattresses at the same time.

We roll a cask-shaped roller over each mattress for 30,000 cycles to simulate approximately eight years' use based on male body types only.

We roll a cask-shaped roller over each mattress for 30,000 cycles to simulate approximately eight years' use based on female body types only.

Using an oscilloscope we measure the movement of the mattress after a standard impact (17.5kg), simulating the turning body of a sleeping person. We also count the number of bounces up and down before the mattress is calm again. Higher-scoring mattresses exhibited fewer bounces and less movement during standard impact.

We roll a cask-shaped roller over each mattress for 30,000 cycles to simulate usage of approximately eight years. Then, we measure height and firmness straight out of the box, and again after this test to note any differences. Models with a higher score showed limited signs of sagging over time. Lower scoring models show increased sagging over time. Models with a higher score will feel almost exactly the same as they did out of the box after eight years of use.

We assess permeability and water intake. Lower scoring models absorb more fluids which can cause damage and odour buildup over time.

We roll a cask-shaped roller over each mattress for 30,000 cycles to simulate approximately eight years' use. Visible damage such as cracking, broken springs or pilling contributes to fatigue score. A higher score means less damage.

A lower score equals stronger packaging odour. Smell is no longer assessed as of May 2020. Existing smell assessments that were conducted prior to this date no longer contribute to the overall score.

Assessed after two weeks of use. A lower score means the mattress still retained packaging odour after a fortnight. Smell is no longer assessed as of May 2020. Existing smell assessments that were conducted prior to this date no longer contribute to the overall score.

The level of firmness based on our tests.

The level of firmness claimed by the retailer.

How warm the mattress feels during use.

'Tested models' should still be available in shops. 'Discontinued models' may still be available second hand or online.

Recommended retail or typical retail price for "retail" mattresses and RRP for bed in a box mattresses.

Mattresses sold at traditional retail stores are often on sale or steep discounts can be obtained by haggling. This data is designed to illustrate the steep markups that are applied to mattresses by retailers and the amount you can save by waiting for a sale and asking for a deal. Bed in a box mattresses are often on sale, but they are typically sold at a lower price point so savings aren't as significant.

Mattresses are cut open to count springs.

A corner of the mattress is cut to count layers and note layer types. A visual cross-section of each mattress is included in the gallery of each product page.

Some bed in a box brands will charge a pickup fee in rural areas, if you wish to exchange the mattress. This varies based on location.

Most bed in a box brands will organise a free pickup in metro areas, if you wish to exchange the mattress.

If applicable. Bed in a box brands offer home trial periods that range from 30 to more than 100 nights. If you're unhappy with your purchase, you can exchange the mattress for a different model (if available) or a full refund.

Occasionally, you'll encounter brands that charge an exchange fee, on top of the pickup costs, if you wish to exchange the mattress.

A mattress with more handles is easier to rotate, flip and move.

Many spring mattresses include a memory foam layer. This is often unadvertised.