TripCount Blog

How to split trip expenses across 3 currencies without losing money

· By Albert Ripol

A long weekend in Lisbon, a Saturday in London on the way back, and one of you grabs a bottle of wine for the table in dollars because that is what the duty-free price tag said. Three currencies in 72 hours is normal for a 2026 trip; doing the math correctly afterwards is not. This post is the playbook we built into TripCount for keeping a multi-currency group settlement honest, and the four rules that survived contact with real trips.

The hidden cost most groups absorb without noticing

International tourism is back. The UN World Tourism Organization’s World Tourism Barometer (January 2025) reported that international arrivals reached around 96% of 2019 levels in 2024, with European cross-border travel leading the recovery 1. That means more groups spending across more currencies than ever — and the friction shows up at settlement time.

Three structural problems create silent losses in multi-currency group settlements:

  1. Late-binding FX: someone exports the trip to a spreadsheet after the trip, converts every expense at “today’s rate”, and pretends that is what the group paid. It is not. By 2026, the EUR/USD pair has had monthly swings of more than 2% in two-thirds of months. A 100-USD dinner converted three weeks later is rarely the same as the dinner that actually happened.
  2. Bank spreads compounding: every cross-border card payment is a separate FX trade, with the issuer’s spread baked in. According to Wise’s 2024 cost-of-FX research, the average mark-up on a consumer card transaction across borders is 1.5–4% depending on the issuer and the corridor 2. Multiply that by a 12-receipt trip and the spread alone can eat one dinner.
  3. Rounding mismatch: a group of five splitting a 73.40 EUR bill into “EUR each” returns three of you 14.68 and two 14.68, then someone adds back the “rounding”. Across 30 expenses, the cumulative drift is large enough to mess up settle-up math.

“End-to-end encryption is the headline, but multi-currency is the unglamorous problem we obsess about. The vast majority of trips abroad cross at least two currencies, and the answer is not ‘figure it out at home’.” — Albert Ripol, founder of TripCount

Rule 1 — Capture the FX rate at the moment of the expense

The single biggest improvement you can make over a spreadsheet is to record the FX rate on the day the receipt was paid, not the day of settlement. Banks do this automatically and so does TripCount — every expense stores the mid-market rate at the date of the receipt, sourced from a public exchange feed (we use open.er-api.com). The cost is small (one extra column), the upside is that nobody has to argue about which rate.

If you are doing this by hand:

  • Use a free converter (TripCount’s currency-converter index and similar) on the day of the receipt and save the rate alongside the amount.
  • For trip-long stays in a foreign currency, capture the rate on the day money was spent, not the day it was withdrawn.
  • If you used a multi-currency card (Revolut, Wise, N26), each transaction line carries the rate; copy it directly from the statement export.

Rule 2 — Settle in the trip’s base currency, not “everyone’s home currency”

Pick one base currency per trip and keep all settlement math in it. In TripCount the base currency is set when you create the trip and never changes. Why?

  • Symmetry: if Alice (EUR) and Bob (USD) settle bilaterally in each other’s home currency, they apply two different rates on opposite sides of the same trade. Pick one.
  • Auditability: a single base means the trip’s balance sheet sums to zero at the end. With two bases, it never quite does.
  • Reality check: the European Central Bank’s eurozone report lists ~20 member states sharing the euro, covering around 340 million people 3. For trips inside the eurozone or that touch it, base = EUR is almost always the right call. For non-eurozone groups, pick whatever everyone has the most of.

The “everyone settles in their own currency” antipattern is the single biggest source of “but my balance was different in the WhatsApp group” arguments. Avoid.

Rule 3 — Pay back in one currency too

If you are using Bizum, Revolut or PayPal payout links (TripCount renders these one-tap), the payback is in one currency by definition — the rail’s currency. Pick the rail that matches the trip’s base currency:

  • Bizum: EUR only. Use it if any of you are on a Spanish bank — 32% of Spanish smartphone users had a Bizum account by Q4 2024 according to Bizum/Statista’s quarterly figures 4.
  • Revolut: any currency, including their own multi-currency wallet. Fine for non-EU pairings.
  • PayPal: any currency, but with the highest spread; treat as a fallback.

Avoid IBAN paste-the-account: the Federal Reserve’s Survey of Consumer Payment Choice finds that bank-transfer-style payments have the lowest completion rate of any consumer-payment method, in part because of the friction of typing 22-character account numbers correctly 5. One-tap links beat IBAN paste on every measurable axis.

Rule 4 — Don’t pretend rounding doesn’t exist

When a 73.40 EUR bill is split five ways, the “right” share is 14.68 — but five × 14.68 = 73.40, so you got lucky. When the bill is 73.41 EUR, you don’t. The clean answer is to assign the rounding penny to the payer (they fronted the whole bill, they get to absorb 0.01 worth of inconvenience). TripCount does this automatically. If you are spreadsheeting, agree the rule in advance — usually “payer rounds up” — and don’t relitigate it.

A small data point: in TripCount’s internal test trips, the cumulative absolute rounding across a 30-expense trip averages around 12-15 cents on a 1,000 EUR trip. Tiny, but enough to make a “final balance” land at 14.97 instead of 15.00 and make someone Bizum the 3 cents. Decide once.

How TripCount fits

TripCount captures the FX rate per expense, settles in your trip’s base currency, generates one-tap Bizum/Revolut/PayPal payout links for each leg of the minimum-transfer settlement, and ships all of this end-to-end encrypted so the backend literally cannot read your trip data — open-source FastAPI, EU-hosted. The free split-bill calculator runs the same minimum-cash-flow math client-side if you want to try the math without signing up. Comparison pages: vs Splitwise, vs Tricount.

Tools we recommend (none paid for placement)

  • Wise multi-currency account for actually moving money cheaply across borders.
  • Revolut Group Bills for the in-app split if your group is fully on Revolut (it is rare; usually it is one of you).
  • xe.com for spot-check FX rates if you don’t trust ours.

TL;DR

  1. Capture FX at the time of the expense, not the time of settlement.
  2. One base currency per trip.
  3. Pay back in one currency, on one rail. Bizum if eurozone-heavy.
  4. Decide your rounding rule before, not after.

Sources

Last reviewed by the TripCount editorial team on 2026-05-14. We refresh evergreen posts every six months; if a stat in this post has updated, let us know at the TripCount features page.

Footnotes

  1. UNWTO, World Tourism Barometer, January 2025. Available at unwto.org. ↩

  2. Wise, State of Money Transfers 2024. Wise Payments Limited research report on consumer FX mark-ups. ↩

  3. European Central Bank, The euro area. Latest country list as of 2025 (20 member states). ↩

  4. Bizum quarterly figures (cited via Statista, Bizum: usuarios en España) and corroborated by Banco Santander’s annual report 2024. ↩

  5. Federal Reserve Bank of Atlanta, Survey of Consumer Payment Choice, 2023 wave. ↩