Our methodology
Every number on SimSift comes from a written, repeatable method. This page is that method. Version 1.0 · last reviewed 15 Oct 2026 · reviewed by Ironbridge, SimSift editorial team
1. Where prices come from
Once live, prices come from the official product feeds that networks publish through the Awin affiliate network, and from each network's own website. A feed price that changes by more than 60% in a day, or that is missing a required field (price, term, data, intro period), is held back and checked by hand before it is published.
2. How often we check
Every deal is re-checked daily at about 06:15 UK time, and twice a day in promotional weeks such as Black Friday. Every page shows the time it was last updated. Once our live feeds are connected, prices will be no more than about 24 hours old. During our preview, the prices shown are examples. Every check is logged in our price-check changelog.
3. True monthly cost
True monthly cost = total paid over the contract ÷ number of months. The total includes introductory prices ending and any mid-contract price rise. Since 17 January 2025, Ofcom requires rises to be set out in pounds and pence, so we can calculate them exactly. 30-day rolling plans are costed over 12 months at today's price.
Worked example: £8 a month for 6 months, then £12, on a 24-month contract with a £1.50 rise each April (taken here as month 7 and month 19). Months 1–6 cost 6 × £8 = £48. Months 7–18 cost 12 × £13.50 = £162. Months 19–24 cost 6 × £15 = £90. That's £300 in total, so the true monthly cost is £300 ÷ 24 = £12.50, not the £8 in the advert.
4. Cost per GB
True monthly cost ÷ monthly data allowance. Unlimited plans don't get a £/GB figure.
5. When we publish a page
Combination pages (for example, 30GB+ deals under £10) are only offered to search engines when they list at least 5 distinct live deals and at least 40% of those deals differ from the broader page they sit under. Other combination pages stay available to visitors but are marked noindex and point search engines to the broader page. We don't publish pages for towns or other variations where there's no real difference in deals.
6. "Cheapest" claims
We only say "cheapest" when the claim comes from the dated table on the same page, and we always say what was compared (for example, "cheapest 30GB+ SIM-only deal we track, checked 15 Oct 2026").
7. What we don't do
Commission never changes the order of deals. There are no paid placements. If we ever add a paid placement, it will be labelled "Sponsored" and kept separate from the ranked list. See How we rank and How we make money.
8. Corrections
Spotted a wrong price? Email [email protected]. We aim to fix confirmed errors within one working day and log them in the changelog.