The unit of measurement to express the change in value between two currencies is called a “pip”, also referred to as price interest point. A pip is the smallest whole unit price move that an exchange rate can make, based on forex market convention.
Most currency pairs are priced out to four decimal places and a single pip is in the last (fourth or second) decimal place.
There are also brokers that quote currency pairs beyond the standard “4 and 2” decimal places to “5 and 3” decimal places, like Mitrade. These are referred to as fractional pips, also called “points” or “pipettes.”
fig 1. For currency pairs and quotes displayed to 5 decimal places
Suppose the price of EUR/USD was 1.13452. After a price movement, if the price of EUR/USD is now 1.13482, it changes by 0.00030, 30 points or 3 pips (from 1.13452 to 1.13482).
fig 2. For currency pairs and quotes displayed to 3 decimal places
There are also currency pairings with 3 decimal places such as USD/JPY. Suppose the price of USD/JPY was 143.118 and after a price movement, if the price of USD/JPY rose to 143.178, it changed by 0.60, 60 points or 6 pips (from 143.118 to 143.178).