How we work this out

Every verdict on this site comes from prices we've recorded ourselves. Here's exactly how.

Where the prices come from

We read the prices each brand or retailer publishes on its own website, for every size it sells. We check each one every hour, or every few hours for retailers with very large ranges. We follow each site's published rules for automated visitors, and we don't get round anything a site blocks.

Some retailers show one "from" price per mattress rather than a price for each size. For those, we track the "from" price, which is usually the smallest size.

What we record

• The price shown for each size.
• Any "was" price shown next to it.
• Discount codes the brand publishes on its own site, and when we first and last saw them.
• The time of every check, which is the "Checked" time on each page.

We only store a new price when it changes, but every check updates the "Checked" time. So a price that hasn't changed for months still shows when we last confirmed it.

Older prices

For dates before we started checking a mattress ourselves, we use archived copies of the retailer's page from Common Crawl, a free public archive of the web. These snapshots are roughly a month apart, so a short sale between two snapshots won't show. Product pages say where this older history begins.

How the verdict works

We compare today's price with every day in our record, up to the last 12 months.

Good time to buy

Today's price is within 3% of the lowest price we've recorded.

Usual price

The mattress has cost today's price or less on at least half of the days we've recorded.

Worth waiting

It has been noticeably cheaper on enough days that today's price isn't special.

Not enough history yet

We give a verdict only once we've recorded at least 30 days of prices.

The price ruler

The ruler runs from the lowest price we've recorded to the "was" price the retailer shows, or to the highest price we've recorded if there's no "was" price. The dark tick marks the usual price: the middle price across all the days we've recorded.

Discount codes

When a brand publishes a code on its own website, we show the price with that code applied and draw it as a separate line on the price history. You'll find the code itself on the brand's website. We don't apply codes that are limited to "selected" products, codes past their end date, or codes with a minimum spend above the price. We can't test codes at checkout, so where a code's terms aren't clear we say so.

What's not included

Our prices don't include delivery charges, bundles, finance offers, or discounts you'd only get by signing up for emails.

Mistakes

Websites change, and occasionally we'll record something wrong. If you spot an error, tell us and we'll check and correct it.