# Revenue & Currency

Track money made by each version and report it in a single currency — Otter converts other currencies for you so the comparison is fair.

Measure the money each version makes — and report it all in one currency, even when your customers pay in several. Otter does the converting for you.

Clicks and sign-ups are useful, but sometimes the real question is: *which version makes more money?* A revenue goal answers that. When a visitor buys something, your site tells Otter the amount and the currency, and we tie that money to the version they saw — so you can compare **revenue per visitor** between versions, not just conversion counts.

The twist: customers often pay in different currencies. To keep the comparison fair, Otter A/B reports everything in one **reporting currency** of your choosing and converts the rest automatically.

## Set your reporting currency

1. **Set a project default** — Open your project's settings and find **Default revenue currency**. Enter a three-letter code (like `USD`, `EUR`, or `GBP`) and save. Every revenue goal in the project uses this unless you say otherwise. New projects start on USD.
2. **Override it for one test (optional)** — When you add a revenue goal in the test wizard, there's a **Use project currency** switch (on by default). Turn it off to type a custom currency for just that goal — useful when a single test should report differently from the rest of your project.

## How conversion works

- **Many currencies in, one currency out.** Payments in other currencies are converted into your reporting currency automatically, so a test with mixed-currency orders still shows one clean revenue number per version.
- **Rates stay fresh.** Exchange rates refresh every day in the background. You never enter or maintain a rate yourself.
- **Your original data is untouched.** The amounts and currencies your site sent are always kept as-is. Changing the reporting currency only changes how they're displayed and added up — so you can switch it anytime without losing anything.

> **Keeping revenue comparable:**
>
> - **Always set a reporting currency if you sell in more than one.** If orders arrive in several currencies and no reporting currency is set, the results page can't safely add them up and will say *"Revenue cannot be compared."* Setting a Default revenue currency fixes it.
> - **Always send both an amount and a currency.** Revenue tracking needs both for every purchase. If some conversions are missing one, that goal's revenue can't be compared. See [Goals](https://www.otterab.com/docs/building-tests/goals) for setting up a revenue goal, and [Reading Results](https://www.otterab.com/docs/analyzing-results/reading-results) for how revenue per visitor is compared.

## Frequently asked questions

### How does Otter track revenue?

When a visitor buys something, your site tells Otter the amount and the currency (your developer sends this with a single line of code). Otter ties that money to the version the visitor saw, so on the results page you can see which version earns more per visitor — not just which gets more clicks.

### What is the reporting currency?

It's the single currency your revenue results are shown in. Even if customers pay in dollars, euros, and pounds, the results page adds everything up in one currency so you're comparing like with like. You set this so the numbers make sense to you.

### How do I set my currency?

Open your project's settings and find "Default revenue currency." Enter a three-letter currency code (like USD, EUR, or GBP) and save. Every revenue goal in that project uses this currency unless you choose otherwise for a specific test. New projects start on USD.

### Can one test use a different currency?

Yes. When you add a revenue goal in the test wizard there's a "Use project currency" switch, which is on by default. Turn it off to type a custom currency for just that goal — handy if one particular test should report in a different currency from the rest of your project.

### What if customers pay in several different currencies?

That's exactly what the reporting currency is for. Otter automatically converts every payment into your chosen currency using up-to-date exchange rates, so a test with mixed-currency orders still gives you one clean, comparable revenue number per version.

### How fresh are the exchange rates?

They're refreshed every day, so conversions reflect recent rates. You don't have to enter or maintain any rates yourself — it happens automatically in the background.

### Why does my report say 'Revenue cannot be compared'?

This appears when Otter can't safely add your revenue up into one number. The usual causes: orders arrived in more than one currency but no reporting currency is set, a currency turned up that there's no exchange rate for, or some conversions are missing their amount or currency. The fix is almost always to set a Default revenue currency in your project settings and make sure your revenue tracking always sends both an amount and a currency.

### Does changing the currency rewrite past results?

Your underlying data (the original amounts and currencies) is always kept exactly as it came in. The reporting currency only changes how those amounts are shown and added up, so you can switch it without losing anything — the results simply re-display in the new currency.

### Do I need a revenue goal to use this?

Yes — currency settings only matter for revenue goals (the goal type that measures money). If your test measures clicks, page views, or sign-ups instead, there's no money involved and the currency setting doesn't apply.

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Canonical page: https://www.otterab.com/docs/building-tests/revenue-and-currency