Methodology

Sources

Official rates: the Central Bank of Nigeria

• US dollar. The closing rate of the Nigerian Foreign Exchange Market (NFEM), with the day's weighted average, high and low, as published by the CBN. We read it from the CBN's own data feed at https://www.cbn.gov.ng/api/GetAllNFEM_Rates, the same data as the CBN's published rates pages.
• Pound sterling, euro and the other currencies. The CBN's daily exchange-rate table: buying, central and selling rates in naira per one unit of each currency. We read it from https://www.cbn.gov.ng/api/GetAllExchangeRates?format=json. Our pound and euro pages headline the central rate.

You can check any figure against the CBN exchange rates page. These feeds are public but not documented by the CBN, so we treat them with care (see validation below).

Reference rate: ExchangeRate-API

Pair pages also show a mid-market reference from the open access service of ExchangeRate-API (“Rates By Exchange Rate API”). It is the midpoint of international buy and sell prices, updated about once a day. It is clearly labelled, is never presented as the official rate, and we show one figure per page for comparison only.

Update times

• The CBN publishes figures for business days only: none for weekends or Nigerian public holidays.
• The CBN gives each figure a date, not a time of day. Figures can appear a day or more after the date they are for.
• We check the CBN at most once an hour. Each page shows the CBN date of its figure and the time we last checked, in West Africa Time (WAT).
• So on a Monday morning, or the day after a holiday, the latest figure is often dated the last business day. That is expected.

How we check the data

• Every row must have a real date and positive numbers; malformed rows are dropped.
• For each currency the CBN buying rate must not exceed the central rate, and the central rate must not exceed the selling rate.
• The dollar, pound and euro must all be present, with at least a week of history, or we reject the whole update.
• If the newest figure moved more than 10% from the day before, we hold it back for a day and say so on the page. A real move that large will still be there on the next CBN publication; a feed error usually will not.
• We never fill a gap, estimate, average across sources or round a figure before showing it.

When the CBN cannot be reached

If the CBN feed fails, or its data fails these checks, we keep showing the last good CBN figures we hold, each with its own CBN date, and a “Couldn't update” note at the top of the page saying when we last checked successfully. We never invent a number to fill the gap.

Converters and rounding

The converters multiply or divide by the CBN figure exactly as published (up to four decimal places), and round only the result for display: two decimal places, or more for very small amounts such as the value of ₦1 in dollars.

Why the rate you are offered differs

The CBN figure is a reference for the official market. The price you get depends on who you deal with:

• Banks price foreign currency around the official market rate, then add their margin and charges, and may limit how much you can buy.
• Licensed bureaux de change (BDCs) buy and sell cash at their own prices, which depend on their supply and costs.
• Money-transfer services and card payments use their own rate, often with a margin built in, plus any fees.
• Street dealers trade outside the official market. Their prices vary by place and by hour and are not recorded by any official source.

For that last reason we do not publish a “parallel” or “black market” rate: there is no reliable, sourced figure to publish.

Limits

• These are indicative, published rates. Nobody will necessarily deal with you at them.
• Nothing on this site is financial, investment or tax advice.
• We show the dollar, pound and euro in detail and the rest of the CBN table as published. See about LagosXchange.