How to budget a trip before you book anything

Most trip budgets fail in the same place: they start from the flight, add a hotel, and treat everything else as rounding. The rounding is a third of the trip. Here is the method we use ourselves, in the order the money actually scales, with the two lines that decide the trip done properly and the small lines handled once, mechanically.

Start with the two lines that decide everything

Flights and accommodation are 50–70% of most trips, and they behave differently from every other line: they are priced per trip, not per day, and they are the only two you can't trim once you've landed. Budget them first, and budget them for real.

For the flight, budget the median, not the cheapest fare you've seen. The cheapest quote on any board is the lucky tail of the distribution: a fare at an hour you wouldn't fly, with a stop you wouldn't accept, that may be gone before you finish reading. The median is what ordinary searches on ordinary dates actually see. Our app shows the median on every search for exactly this reason; if you're planning by hand, the reliable proxy is to check three nearby date pairs and take the middle result. A worked example from our own December price data: São Paulo–Lisbon quoted €864 cheapest against a €966 median. Budget the €864 and you start €100 behind; budget the median and every quote below it feels like a win instead of every quote above it feeling like a scam.

For accommodation, the unit is the stay, not the night: nightly rate × nights, plus the city tax most European capitals now levy per person per night, plus whatever the apartment listing adds as a cleaning fee. That last line is why apartments beat hotels only from about four nights up, because the fee amortises. A realistic check: the cheapest central-ish quote on our searches usually sits 20–30% under the median, and it is usually 20–30% further from the centre. Paying the median to sleep where your evenings actually are is usually the right buy.

The lines that scale with days

Everything after the two big lines is a per-day number times your trip length, and each has a ceiling worth naming before you travel:

• Food. Decide your tier, budget, mid-range or premium, and write the number down. Our food budget guide defines the tiers across ten cities; they run from €31 a day to €84 a day at mid-range depending on where you are. The tier you choose at the table matters more than the city.
• Getting around. Local transport is almost always a flat, small number (€2–8 a day in our data) because capitals sell day-capped passes. The line that isn't small is airport transfers, both ends. Price them explicitly; they hide nowhere else.
• Doing things. One paid sight per day is the pattern most happy trips follow. Budget one median ticket per day plus a margin, not a list of everything with an entrance fee.

Then add the buffer, once

Add 10–15% to the total. This is not slush; it has a job. It absorbs the checked bag you end up buying at midnight, the taxi when the metro is shut, the card fee you didn't see coming, the exchange spread at the airport kiosk. Our hidden costs guide lists the usual suspects. If the buffer survives the trip, it rolls into the next one.

When the total comes back over budget

The method also tells you where to cut, and the order matters. Nights come off the middle of the trip: six nights prices almost like seven on the big lines and removes a full day of everything else. The accommodation median steps down before the location does, because the cheapest credible room in a fine neighbourhood beats the fancy room you'll sleep in with the shutters closed. The food tier steps down last and only partly, because a week entirely at the budget tier is a different holiday, not the same one for less. Flights cut last of all, since on most corridors the cheapest fare two days away from your dates is a different itinerary, not a discount on this one.

A worked budget, on purpose-made numbers

Round numbers, illustrative city, seven nights, one traveller:

That is the whole method: two researched lines, three per-day lines, one buffer. And every number above can be replaced with the live equivalents from a single search in the app, which is the one-click version of this page.