# Meta Ads in another currency: converting spend for ROAS

> Why spend and revenue can sit in different currencies, how the conversion works day by day, and how to check it.

Canonical: https://atrby.site/blog/meta-ads-currency-roas
Last updated: 2026-10-26

## Why the currencies differ

A Meta ad account is billed in one currency. Your store might take payments in another. If the account is in euros and your Stripe payments are in dollars, a ROAS of 3 in one currency is not a ROAS of 3 in the other.

The number is only meaningful when both sides are in the same currency, on the same day.

## Where the currency comes from

atrby reads the currency from the file. The layout it reads puts the currency in the spend column header, for example `Amount spent (EUR)`. Google's Analytics import guide names the cost column for Meta `Total Spend (Cost)` in its template, so check which header your export uses.

If the file has no currency, atrby assumes your workspace currency and marks that on the review screen. Check that assumption before you publish, because it changes every number in the import.

## How the conversion works

Each row is converted on its own day. Spend on 3 March uses the rate for 3 March, not today's rate, so a campaign's history doesn't move when the exchange rate does.

The rates are the European Central Bank's published reference rates. Here is an illustration, with a made-up rate: 1,000 EUR at 1.10 dollars per euro is 1,100 USD for that day. The row stores both the original amount and the converted one.

If a day has no rate, the row is rejected with the reason. atrby doesn't fill the gap with a neighbouring day's rate, because that would quietly change the number.

## Checking the conversion

1. Pick one day with spend and look up the ECB reference rate for that day.
2. Multiply the original amount by the rate and compare it with the converted amount on the review screen.
3. Check the total spend in your workspace currency against the sum of the converted rows.

If they match, the conversion is doing what it should. If the review shows a different currency from the one you expected, fix the header or the workspace currency before you publish.

## What this means for ROAS

Revenue and spend are both in your workspace currency, so the ROAS on the Revenue screen is a like-for-like number. It is still only as good as the rate on each day, so small day-to-day moves in the exchange rate can shift a campaign's ROAS a little.

For a campaign that runs across weeks, compare the totals over the same window rather than single days.

## The limits

- **The rates are reference rates.** Your bank or card processor may charge a different rate on the day of payment.
- **Revenue uses the same rates.** Each payment is converted at the rate for its payment day, from the same ECB reference rates, so both sides sit on one basis. Your bank's rate on the day can differ.
- **Days are UTC.** A day boundary can split one campaign's spend across two rates.

## Related
- [Import Google Ads spend into your analytics, step by step](https://atrby.site/blog/import-google-ads-spend)
- [Moving from Google Analytics in an afternoon](https://atrby.site/blog/moving-from-ga4)
- [How to calculate ROAS per campaign from Stripe payments](https://atrby.site/blog/roas-per-campaign-stripe)