# Set your base currency & work in multiple currencies

**Category:** [Accounting](https://help.totalctrl.app/hc/totalctrl/totalctrl-help-center/en-US/categories/accounting)
**Updated:** 2026-08-19

Your **base (functional) currency** is the single currency every report is expressed in. Set it in *Accounting → Settings → Currency* before you post entries — it can't be changed once a ledger exists.
## How foreign transactions work

- Invoice or bill in any currency. Each journal line stores the original amount *and* the converted base-currency amount at that day's exchange rate.
- Reports (trial balance, balance sheet, P&L) always sum the base-currency amounts, so nothing mixes currencies.
- When a foreign invoice is paid at a different rate than it was issued, the difference posts automatically to **Foreign Exchange Gain/Loss** (a realized FX gain or loss).

## Exchange rates

Rates refresh automatically every day. You can also click **Refresh rates** in Settings to pull the latest immediately. At month-end, use **Revalue open balances** on the Close page to restate any open foreign A/R and A/P to the period-end rate (an unrealized FX adjustment).

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## Related Articles

- [Accounting overview](https://help.totalctrl.app/en-US/articles/accounting-overview-2)
- [Payroll: connect Gusto or record runs manually](https://help.totalctrl.app/en-US/articles/payroll)
- [Sales tax: rates and the tax report](https://help.totalctrl.app/en-US/articles/sales-tax)
- [Accounting overview](https://help.totalctrl.app/en-US/articles/accounting-overview-1)
- [Create and send an invoice](https://help.totalctrl.app/en-US/articles/create-an-invoice)

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