When you see "€40-€110" on a route page, that is not a quote. It is a calibrated range derived from typical operator pricing per kilometre, adjusted by a corridor-specific multiplier that reflects how competitive and how busy a given route tends to be. Here is the actual recipe behind the numbers.
For trains, the lower bound assumes you booked six to eight weeks ahead at advance-purchase fares with no flexibility. The upper bound assumes a walk-up ticket bought at the station on the day of travel. The gap between the two is unusually wide on European trains: in many countries advance fares run 50 to 70 percent below the standard ticket, so the same seat can cost €35 or €95 depending only on when you press buy.
A worked example makes the spread concrete. On Paris to Amsterdam, a Eurostar advance fare booked two months out sits near €39, while the same train bought walk-up on a Friday evening can reach €130, so our range for that corridor reads roughly €40 to €130. On Rome to Florence, a Frecciarossa advance seat costs about €19 against a flexible fare near €55. On Berlin to Munich, ICE fares swing from €18 saver tickets to €150 full-flex. The wider the real-world gap on a route, the more our published range stretches to match it.
For buses, the range is narrower, because most coach operators such as FlixBus and BlaBlaCar Bus use demand-based pricing without the extreme advance-purchase discount. Buy a day ahead and you will typically land within 30 percent of the price you would have paid two weeks earlier.
For flights, the range reflects the split between low-cost and full-service carriers. A €50 Ryanair fare and a €200 Air France fare on the same route are both genuine prices. Ryanair charges extra for seat selection and baggage, while Air France folds those costs into the headline number, so the range tries to capture both ends honestly rather than picking a single misleading figure.
For cars, the range covers fuel only. The minimum assumes a small efficient car and reasonable pump prices, the maximum a thirstier vehicle on the same distance. We deliberately leave out tolls, which vary enormously by country, and vehicle depreciation, which often dominates the true cost per trip once you account for ownership.
What this is not is a live search engine. We do not talk to operator APIs, we do not reflect today's specific fares, and we cannot tell you what seats are available next Tuesday. Treat the range as a way to set expectations and sketch a budget, then book on the operator's own website once your dates are fixed.
What should you do when the operator quotes a price above our range? There are two likely explanations. Either you are booking at the last minute, in which case moving your trip forward two or three weeks usually helps, or you have landed on a peak-travel weekend such as Christmas, the summer school holidays or a French national holiday. Our ranges aim for the typical case, not the peak, so a quote near or above the upper bound is a useful signal to check your dates before you commit.