In plain English
What Contract size means
Contract size tells you how much market exposure one CFD controls. For a share CFD, one contract may represent one share; for an index CFD, one contract may represent a cash amount per index point. It is the multiplier used to translate price movement into profit, loss, and margin calculations.
Why it matters
Without contract size, the quoted price alone is misleading. A one-point move can mean very different cash outcomes depending on the contract multiplier. Contract size also affects position sizing, margin required, and how large any financing or dividend adjustment will be.
Example
If an index CFD has a contract size of 1 per index point and the index rises from 7,000 to 7,015, one long contract gains 15 units of the account currency before costs. If the contract size were 10 per point, the same move would be 150 units. This is simplified.
Quick answers
Common questions
Is contract size always the same across brokers?+
No. It depends on the product and the provider’s contract specification.
Does contract size affect margin?+
Yes. Larger contract size generally means larger notional exposure and, therefore, more margin.
Sources