Every number on this site comes from prices Fareband observed itself and stored, with the date of observation. This page explains how that works. It is linked from every data component on the site.
Once a day, Fareband queries fares for each route it tracks and stores every result as an observation, together with the departure and return dates, the trip type, the carrier, the currency and the moment it was read. Prices are stored as whole units of the smallest denomination of their currency, pence, cents, yen, so no rounding error can accumulate. Nothing is averaged before storage, and no observation is edited after the fact.
A price is a fare that was available at the moment it was read. It is not a prediction, not a guarantee, and not an offer. Fares change constantly, and the figure you see when you follow a link may differ from the one recorded here.
For each route Fareband computes a band over a rolling window, usually 90 days, from all observations of that route in that window. The 10th percentile is the price that 10% of observations fell at or below. The median is the middle observation. The 90th percentile is the price only 10% of observations exceeded.
The band describes what this route has actually cost recently. It says nothing about what any individual traveller paid, and it does not adjust for cabin class, baggage or how far ahead the booking was made. Observations in different currencies are never mixed inside one band.
A route page becomes indexable only once it has at least 60 observations, at least 90 days since its first observation, fares on at least 45 distinct days inside that span, and fares from at least 3 distinct carriers. The 45-day rule exists because a span is not coverage, a route observed on day one and day ninety has ninety days of history and two days of data. Below any of those thresholds the page stays out of search results and keeps collecting. A page that cannot show an observed figure with its date does not publish at all.
The guides carry a second kind of figure, a price read by a person on a provider’s public page, per plan, before checkout, in the currency the page displayed, on one date. Those tables say so beneath them, name the page each price was read from, and are not averaged, not adjusted and not refreshed automatically. When a provider is one we earn from, its rows link through our tracked redirect and the table says which rows those are. Reference rows are providers we do not earn from, included so the comparison is not a comparison between our partners only.
A number on its own is an assertion. A number with the day it was read, and the address of the page it was read from, is checkable by anyone who doubts it. That is not pedantry, and one worked case shows why.
Radical Storage runs a luggage storage network. On 15 September 2026 its Madrid guide page stated, under the heading Security Guarantee, “Every item stored with Radical Storage partners is covered by a €10,000 guarantee”. Higher up the same page the same guarantee appeared as “3,000 euros guarantee for each stored item”, and its own comparison table gave it a third time as “Yes (up to £3,000)”, in pounds. Three figures and two currencies for one guarantee, on one page, read in one sitting.
The contract says something else again. Read the same day, clause 9 of the terms and conditions states “Each Bag is covered with a Radical Storage Guarantee for a value of € 3000”, and clause 9.4 puts the ceiling on it, “the Company will pay up to a maximum of €3000 per claim to repair or replace (at our discretion) your property”. Per claim, and clause 9.8.3 excludes anything above that limit arising out of one or more bookings by the same claimant. So three bags lost together are covered to €3,000 in total, not to €9,000, and the €10,000 on the marketing page is not a figure a traveller can rely on.
None of that is an accusation of bad faith. Marketing pages are written by people who are not holding the contract open, and they go stale quietly. That is the reason for the rule rather than an exception to it. So a figure here is quoted from the page we read, names that page, and carries the date, which is what lets a reader catch it when it changes.
Read 15 September 2026 from
radicalstorage.com/travel/madrid-luggage-storage-guide-2025/, which shows its own
last-modified date of 28 August 2026, and from radicalstorage.com/terms-and-conditions.
Radical Storage is a company we are contracted with and have placed no link for, which our
affiliate disclosure states.
Where a source refuses an automated fetch, we read it by hand in a browser and record the same two things, the exact address and the day. A figure nobody here has read does not go on a page at all.
Observations are collected daily. Bands are recomputed nightly for the 30, 90 and 365-day windows. The date shown beneath a price band is the date of the observation it describes, not the date the page was last rebuilt.
When a figure turns out to be wrong, the page is corrected and the correction is noted with its date rather than quietly overwritten.