Splitting expenses across multiple currencies, honestly
Last updated by The EvenRound team.
Eight friends, three countries, two weeks. Here's what actually happens to your money.
Multi-currency expense splitting sounds straightforward in theory - log expenses in their local currency, convert at settlement - but the details matter. Whose exchange rate? Snapshotted when? What about the friend whose Wise account converts at a different rate from your bank? This guide covers the honest mechanics so your group doesn't end up arguing about FX margins of 0.3%.
Snapshotted FX vs live FX at settlement
There are two schools of thought. Snapshotted FX (used by EvenRound) locks the exchange rate at the time the expense is logged. So a €40 dinner in Lisbon on day 1 is always €40, and the GBP equivalent is fixed at day 1's rate. Live FX (used by some apps) re-converts at the moment of settlement, meaning the €40 might suddenly cost £35 or £37 depending on how rates moved during the trip. Snapshotted is fairer because it reflects what the money was actually worth at the time of spending.
Whose rate? The provider question
FX rates aren't a single number - they vary by source. The European Central Bank reference rate is the most-cited 'mid-market' rate. Banks add a 1-3% margin. Wise and Revolut add 0.3-0.7%. Cash bureaux add 4-8%. EvenRound uses the ECB rate (mid-market) for snapshotting. When the actual settlement happens via Wise or Revolut, the user pays at their provider's rate - but the EvenRound plan is computed at mid-market, so neither party is gaming the other.
What can go wrong
Common failure modes: (1) one person logs an expense in the 'wrong' currency by accident (logs €40 instead of $40), creating a 10% error; (2) the app uses bank-of-record rates rather than mid-market, baking in a 2% margin; (3) one person settles via PayPal F&F (which converts at 4% above mid-market) without the group knowing. Solution to all three: use snapshotted mid-market rates and settle via Wise or Revolut.
Worked example: 5-day Iceland trip
Group of 4: 2 in EUR, 2 in GBP. Trip costs ISK 280,000 in expenses. Logged in ISK as they happened, snapshotted at day-of rates. Final balances: GBP user A owes EUR user C £280 (snapshotted), GBP user B owes EUR user D £225. Settled via Wise at trip end. ECB rate at logging matches Wise's actual conversion within 0.5%; nobody complained.
When live FX is acceptable
If your group is settling weekly during a long-running scenario (e.g., shared rent in a multi-currency household), live FX at settlement can be fine because the timeframes are short. For trip groups, snapshotted is universally better - you don't want a lazy roommate's late settlement to capture an FX move.
Multi-currency works well if you commit to snapshotted FX at mid-market rates and settle via low-spread rails like Wise or Revolut. Most arguments about money in multi-currency groups are actually arguments about which rate was used.