Currencies and Exchange Rates¶

Updated 22 October 2026

PNLCS keeps its books in one currency, the default currency. Every price, invoice amount, credit balance, refund and report is in it. Other currencies are for showing prices to customers and for the currency an invoice is billed in; their amounts are always converted from the default currency at a rate.

Currencies are under Setup → Currencies. A new installation has four: USD (the default), EUR, GBP and TRY, with placeholder rates that the first rate update replaces.

Add a currency¶

Setup → Currencies → + Add Currency:

Amounts always have two decimals. Edit changes the same fields. A currency can be deleted only if it is not the default and no customer is billed in it: the Customers column counts them, and you move those customers to another currency on their profiles first.

The default currency¶

Make default on a currency's row makes it the books currency. It changes nothing else: prices are not converted and rates are not recalculated. Press Update rates now straight afterwards, so every rate is against the new default.

Prices in other currencies¶

A product's Pricing box has one block per currency. The shop, the cart, and the invoices all use the block of the default currency (or the first block that has prices, if the default one has none). The other blocks are only used once their currency becomes the default.

A price shown in another currency is always the default-currency price multiplied by that currency's rate, rounded to two decimals. Domain prices and invoice items have no currency of their own and are converted the same way.

Rate updates¶

With Update exchange rates every day ticked (card Customer currency and exchange rates on Setup → Currencies; on by default), rates are fetched every morning at 05:30, against the default currency. Update rates now fetches them at once, whether the daily update is on or not.

• Rates come from open.er-api.com; if that fails, from frankfurter.app (European Central Bank reference rates). Neither needs a key.
• Each rate is stored with five decimals. A currency neither source quotes keeps the rate it had.
• The default currency's rate is set back to 1.
• If both sources fail, every rate is kept as it was and the run reports an error.

A rate you type by hand is overwritten by the next update. To keep your own rates, untick Update exchange rates every day.

The command is pnlcs:currency-update (Scheduled Commands).

Official lira rate (TCMB)¶

For a shop whose default currency is USD and that has TRY, the lira rate can come from the Central Bank of the Republic of Turkey instead, so customers can check it. Under Setup → General Settings → Billing currency:

• Official rate source: None (commercial rate) (the default) or TCMB (Central Bank of Turkey).
• TCMB rate: forex selling rate (the default) or forex buying rate.

Each update then takes the USD rate from the latest TCMB bulletin (the bank publishes on business days, so on a weekend it is Friday's) and remembers its date and bulletin number for the invoice note. If TCMB cannot be reached, the commercial rate stays for that day. Other base currencies are not affected.

Which currency an invoice is billed in¶

Amounts on an invoice are always in the default currency. An invoice can also carry a billing currency: the currency the customer pays in, with the rate fixed on the day the invoice was created. Reprinting it later shows the same figure.

PNLCS picks the billing currency in this order:

1. The customer's own currency, when Let customers choose their currency is on and their account has a currency other than the default.
2. Bill customers in (Setup → General Settings → Billing currency), when it is set to a currency other than the default. The default choice is Shop currency only.
3. Otherwise none: the invoice is in the default currency only.

How a card payment is charged depends on the gateway: in the default currency, unless its Charge in the invoice's billing currency option is on (Payment Gateways).

Letting customers choose¶

Let customers choose their currency (Setup → Currencies, off by default) needs at least two currencies.

• A visitor picks a currency in the top bar and sees every price converted at the current rate. The cart and checkout say which rate is used and that the invoice will be in that currency.
• The account they open keeps that currency. After that, a signed-in customer cannot change it: staff do, under Clients → the client → Edit → Currency.
• The admin area always shows the default currency.

On the invoice PDF¶

Lines and totals are printed in the default currency. An invoice with a billing currency adds an Amount due (TRY) line (with that invoice's currency code) and a note under the totals:

• with a commercial rate: Billed in TRY, converted from USD at a rate of 41.8500.
• with the TCMB rate: Converted at the forex selling rate published by TCMB on 21.10.2026: 1 USD = 41.8500 TRY (bulletin 2026/201)

The rate is printed with four decimals.

Rounding¶

• A converted amount is the amount times the rate, rounded to two decimals. On an invoice, only the total is converted, so line amounts in the billing currency are never added up and cannot drift from it.
• Add Funds asks for the amount in the billing currency. It is divided by the rate and rounded to two decimals; that figure goes on the invoice and, once paid, on the credit balance. The quick amounts (10 to 500 in the default currency) are converted and rounded to round figures, and so are the limits: 5 to 10,000 in the default currency.