Multi-currency

Plutus keeps three things distinct when a connected cost source bills in a currency other than your display currency: what the provider actually charged, a common base figure used for totals, and the figure you see on screen.

What’s captured

Every cost record keeps the amount exactly as the provider billed it, plus the ISO 4217 currency code it was billed in. This is invoice truth — it never changes, so you can always reconcile a figure in Plutus against the provider’s own invoice.

Alongside that, Plutus converts the same amount to a USD base figure, using the exchange rate in effect on the date the cost was incurred (not today’s rate). The base figure is what every total, chart, and aggregate is built from — this is what lets Plutus add AWS spend billed in USD to Hetzner spend billed in EUR into one correct account total, instead of adding two different currencies together as if they were the same number.

If a cost source’s currency can’t be determined for a given sync, that sync fails rather than guessing. Manual cost sources take the currency you enter when you create them. A silently wrong currency (for example, treating euros as dollars) produces a total that’s off by the exchange rate and looks completely plausible on screen, which makes it much harder to catch than a failed sync.

Choosing a display currency

You can pick which currency cost figures are shown in. Plutus resolves your display currency in this order, each level overriding the one before it:

1. Account default, set by an admin.
2. Your own preference, per account — useful if you belong to a US-based org and a UK-based org and want each to show in its own currency.
3. A one-off override on a single chart, which applies only to that view and isn’t saved.

If none of these is set, figures show in USD. A stored preference for a currency Plutus holds no exchange rate for also falls back to USD.

Converting to your display currency happens instantly, without a server round trip, because the underlying figure is already stored as a USD base amount — showing it in another currency is one multiplication by the current rate, not a new query.

Worked example: an account has AWS billing in USD and Azure billing in EUR. Viewed with GBP as the display currency, both providers’ spend is converted from their stored USD base figure into GBP at today’s rate, and the account total is the sum of both — a single number in one currency, even though nothing was actually billed in GBP.

Because a converted figure moves with the exchange rate, it’s only ever “correct as of now.” A chart you looked at yesterday and the same chart today can show a slightly different total in your display currency even though nothing about the underlying spend changed — only the rate did.

What does not convert

A few figures are deliberately fixed to one currency and ignore your display currency setting. Seeing a number that doesn’t match the rest of the page in these cases isn’t a bug:

• Budgets. A budget carries its own currency, set when it’s created. A £5,000 budget is always evaluated and displayed as £5,000 — spend is converted into the budget’s currency for comparison, not the other way around. The rate used is the one for that budget period, not today’s, so a closed period’s status never moves. Changing your display currency preference doesn’t change what currency a budget is denominated in.
• Savings and commitment recommendation quotes. These come from a provider’s own recommendation engine (AWS, Azure, GCP) and are shown in whatever currency that provider quoted them in, so the number matches what you’d see in the provider’s own console. Account-level totals across multiple recommendations still convert to a common base so they can be summed.
• Plan pricing, tier spend limits, and overage. What Plutus charges you and what your plan allows are quoted in the currency you’re billed in. Your display currency setting doesn’t change them.

The reasoning is the same in all three cases: these are commercial or provider-quoted figures, not spend totals being re-expressed for convenience. Letting them drift with a display currency you can change at any time would make a budget threshold, a savings estimate, or your own bill inconsistent from one moment to the next.