Start with one selling currency
The selling currency is the currency your traveller sees and pays. Choose it once for the departure. A supplier currency is different: it belongs to the quote and should remain attached to that cost even after you calculate a converted value.
A common spreadsheet error is to label the final column USD and then add EUR, GBP and USD rows as though the labels changed the money. The total looks precise while the underlying arithmetic has no shared unit.
Record the rate as a decision
For each foreign currency, record the direction of the rate, the date, and the source or policy used. For example: 1 EUR = 1.10 USD, recorded on 12 September for this planning version.
Rates used for a planning price do not need to predict the future. They need to be explicit enough that another person can reproduce the calculation and update it deliberately.
- Keep the quoted amount and currency unchanged.
- Use one documented rate per currency for the pricing version.
- Add any contingency for exchange-rate movement as its own visible rule.
- Recheck rates before a price commitment or major supplier payment.
Convert line by line before totaling
Suppose the ground package is EUR 10,000 and the coach is GBP 3,000. At 1 EUR = 1.10 USD and 1 GBP = 1.28 USD, their planning values are USD 11,000 and USD 3,840. The combined planning cost is USD 14,840—not USD 13,000.
The same method applies before per-person allocation, margin and break-even calculations. Converting after costs have already been mixed cannot repair the earlier total.
Stop when a rate or currency is missing
An unidentified currency or missing rate is a pricing input, not a rounding issue. Hold that line out of the price and ask for the missing information. A visible hold protects the operator from quoting one currency as another.
When the input arrives, update the affected rate, recalculate the group-size scenarios, and keep the earlier pricing version so the movement can be explained.
Put the lesson to work
Give one real departure a calmer home.
Bring the spreadsheet, supplier emails and next actions together, so the answer is there when you come back. Viabasis is invitation-only during the pilot.