How to work out the real cost of any trade before you open it, and why the spread actually matters to your results.
The spread is the difference between the buy price (Ask) and sell price (Bid) for any instrument at a given moment. It's essentially how a broker earns money (or part of it) instead of, or alongside, a separate commission on certain account types.
Every trade you open starts "below zero" by the spread amount — the price needs to move in your favour by at least the spread before you're actually in profit.
A wider spread means you need a bigger price move to break even — which affects short-term traders (scalpers) or anyone opening many trades per day more than long-term traders.
Most major brokers (covered in the broker guide) run variable spreads on their Raw/Zero account types.
Say you open a 1-lot gold position (100 ounces), with a 0.30 spread:
If you're opening many trades over a month, the difference between a 0.10 spread and a 0.40 spread adds up fast and eats into net profits.