How the NBC Exchange Rate Works (and Why It Changes Every Day)

Cambodia runs a dollarized economy, but its official currency is the riel (KHR), and the two circulate side by side. Prices are often quoted in dollars, taxes and government fees are usually calculated in riel, and the rate that connects the two changes daily. That rate is set by the National Bank of Cambodia, and nearly every business in the country ends up needing it somewhere in their accounting.

Who sets the rate, and when

The National Bank of Cambodia (NBC) publishes an official exchange rate for the US dollar against the riel each working day, in the late afternoon. This is the rate used as a reference for accounting, invoicing, and tax filings in Cambodia. It is not a market rate that moves minute to minute. It is a single daily figure that businesses are expected to apply consistently.

Official rate vs. bank and market rates

Banks and money changers quote their own buy/sell rates throughout the day, and those rates move with supply and demand. The NBC rate is different: it is a single reference figure published once a day, and it is the one Cambodian accounting and tax practice expects, not whatever a bank counter is quoting at the time.

Why it matters for bookkeeping

Any business invoicing in both USD and KHR, which covers most businesses in Cambodia, has to convert between the two using the same rate the tax authority expects. Applying yesterday's rate, or rounding differently, lets your books and your tax filings drift out of alignment without anyone noticing. It is a small number with a large effect on financial accuracy.

The manual way most businesses handle it

In practice, someone on the finance team checks the NBC rate each morning or afternoon, and enters it into whatever system runs the books, whether that is an ERP, a POS, or a spreadsheet. It is a small task, repeated every working day for as long as the business exists. Miss a day and every transaction until the next update uses a rate that is already out of date.

Automating it

Because NBC publishes the rate in a consistent, checkable place, the whole lookup and entry routine can be automated: record the published rate, check it against recent history, and write it into whatever system needs it. That is the approach RielSync takes for Odoo, SambaPOS, QuickBooks Online, Zoho Books, and SAP Business One. There is more detail in how it works.