How I budget for currency exchange fluctuations on long trips and why this matters more than most guides suggest.

The problem: you plan a 3-month trip with a $3,000 budget at current exchange rates. By month 2, the currency of your home country has weakened 8% against the dollar. Your real budget is now $2,760. The reverse is also possible — your currency strengthens and you have more than expected.

The planning approach: use a slightly conservative exchange rate assumption (5-10% worse than current rates) when estimating trip costs. This creates a natural buffer. If rates stay favorable, you have extra budget. If they weaken, you're protected.

The execution approach: don't convert all your money to a single destination currency at the start of the trip. Keep your reserves in your home currency (or USD) and convert as needed. This means you convert at whatever the rate is when you need money, rather than locking in a rate months before you need it.

The Wise card advantage: Wise converts at mid-market rates in real time. Holding a balance in your home currency and spending in local currency via Wise means you get the current rate, not a rate locked in weeks earlier.

For long trips: the variance over 3 months can be significant. A 10% swing in a major currency pair is not unusual. Budget for this explicitly rather than hoping the rate stays favorable.