The World Sleep Almanac is how World Day turns a mattress’s published facts into a score you can check. Most mattress reviews, comparisons and buying guides on World Day end with a “World Sleep Almanac score” block: three to five criteria, each scored out of 10, and an overall score that is simply their average. This page explains what we look at, how we score it, and what the score does not mean.
What does the World Sleep Almanac score measure?
The score measures how well a mattress is documented and backed for a US buyer: the protection you get if it does not suit you, how long the maker stands behind it, what it is made of, what it costs compared with similar mattresses, and what owners report in public. It does not measure how a mattress will feel to you, because feel depends on your body, your sleep position and your preferences.
Which criteria do we score?
Each page scores the three to five criteria that matter for the decision it covers, chosen from this list:
- Trial and returns: the length of the home trial, whether a return costs money (pickup or processing fees), and conditions such as a minimum break-in period.
- Warranty: how long the warranty runs, whether it is prorated, what counts as a defect (for example the depth of a body impression), and any fee to file a claim.
- Materials and construction: how clearly the maker documents layers, coil systems, foam types and certifications such as CertiPUR-US, and whether the build fits the sleepers the mattress is sold to.
- Price at equal size: the listed price in one size, usually Queen, compared with mattresses of a similar type and build.
- Public customer reviews: what owners report in public, including recurring complaints, read with caution because reviews hosted on a brand’s own site are moderated by that brand.
The overall score is the plain average of the criteria shown in the block, rounded to one decimal. Every sub-score is printed on the page, so you can recompute it yourself.
Where do the facts come from?
Trial length, return fees, warranty terms, layer descriptions, sizes and listed prices come from the manufacturer’s official product and policy pages, as stated there when the article was last written or updated; the date at the top of the article shows that update. Prices and terms change, so check the official page before you buy. When the official page does not publish a fact, we do not invent a figure for it.
Do we test mattresses in a lab?
No. The World Sleep Almanac is desk research, not a sleep lab. We do not run firmness, heat or motion-transfer measurements, and we do not claim to. When a page describes how a mattress is likely to feel, that reading comes from the maker’s stated firmness and construction: it is an editorial reading, not a measurement.
Does a score mean a mattress helps with pain?
No. A mattress is not a medical treatment, and no score on this site means a mattress treats back pain or any other condition. Pages about pain or health conditions carry a reminder to talk to a doctor or a qualified health professional before changing your mattress.
How do affiliate links affect the score?
World Day is reader-supported. Some links on our mattress pages are affiliate links, mainly to Saatva, and we may earn a commission when you buy through them, at no extra cost to you. Affiliate links are marked as sponsored. Commissions never change a verdict or a score: the criteria and their scores are on the page for anyone to check. On reviews of other brands, the brand under review stays the subject and Saatva is mentioned as an alternative.
How often are scores updated?
A score reflects the facts published on the official page when the article was last written or updated, as shown by the date at the top. Because each page scores the criteria that matter for its own decision, the block for one mattress can differ between its review and a buying guide.
Who writes the World Sleep Almanac?
The World Sleep Almanac is published by World Day (journee-mondiale.com). Each article shows its byline and the date it was published or last updated.
How can you report an error?
If a fact or a score is wrong, email [email protected] with the page address and a source that shows the correct information. Corrections are checked against the manufacturer’s official page.
Where should you start?
Browse all mattress reviews, comparisons and guides, start with the best mattress overall, or see how the Saatva lineup ranks.