A contract specification is the broker's published rulebook for a single tradable instrument. It sets out the contract size behind one lot, the minimum and maximum order volume, the quote currency, the number of decimal places, the tick or point value, the margin requirement, trading hours, and how swaps or overnight financing are charged.
Because CFD instruments are not standardised by an exchange, two brokers can list the same index or commodity with different contract sizes, so "one lot" may carry very different exposure from one platform to the next. Reading the contract specifications — sometimes labelled instrument details or trading conditions — before opening a position is the only reliable way to know what a single lot actually risks.
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Guide
How to Read a Contract Specification
Contract size, tick value, margin requirement, trading hours and swap all live in one table — and every one of them changes what a trade actually costs.