Methodology
What this page covers
Our how we rank page explains the method in plain English. This page is the technical version: exactly where the data comes from, the formulas we run, and how you can verify any number yourself.
How the data flows
Catalogue syncWe pull plans and prices from provider catalogues through automated feeds, never by typing numbers in.
NormalisationEvery plan is reduced to the same fields: data amount, validity, price, coverage, 5G, top up and hotspot support.
Price mathsWe compute price per GB = plan price divided by data in GB, rounded to the cent, at the moment of the check.
SnapshotEach check writes a timestamped record of every country's cheapest rate. That timestamp appears on every page.
How price movement is measured
Movement compares the latest snapshot against the previous one, per country. A green arrow with a percentage means the cheapest rate genuinely fell between two timestamped checks. A red arrow means it rose. A dot means it did not move. We never display a movement that the snapshot history cannot back, which is why arrows only appear when prices actually change.
How provider ratings are computed
Provider star ratings are calculated, not chosen: 45 percent value for money (the provider's median price per GB against the market median), 35 percent country coverage, and 20 percent features (5G, top ups, hotspot support). Each provider page shows its own component scores as bars. The rating updates automatically whenever prices change, and no human can adjust it.
How unlimited plans are handled
A plan without a fixed data amount has no honest price per GB, so we do not invent one. Unlimited plans sort after fixed plans in every table, and the country guides explain the fair use rules that usually apply to them, such as daily full speed caps.
Where the country research comes from
The network, coverage, and local rules content on country pages comes from researched sources: regulators, operators, measurement firms and official guidance, checked at the time of research. Where a fact could not be verified, the field was left empty rather than guessed. Statistics that are old are dated in the text.
How reviews are moderated
Every user review is held unpublished until a human reads it. We reject fake, abusive, or self serving reviews, including providers reviewing themselves or rivals. Providers cannot pay to add, edit, or remove a review.
Check our work
Every page carries the exact GMT timestamp of the last price check. The Price Index can be downloaded as CSV and reused with credit. If you find a number that does not match a provider's checkout, tell us at hello@esimwatchdog.com and we will correct it.