The spread, explained simply
Every tradable market has two prices: the price you can buy at (the ask) and the price you can sell at (the bid). The spread is the gap between them. If EUR/USD is quoted 1.10000 / 1.10012, the spread is 1.2 pips.
When you open a trade you pay the spread immediately — you buy at the higher ask and could only sell back at the lower bid — so a position starts slightly negative and needs the market to move in your favour by at least the spread just to break even.
Why spreads move
Spreads aren't fixed. They tighten when a market is liquid (major pairs during London/New York overlap) and widen when liquidity dries up (rollover time, weekends, exotic pairs) or when volatility spikes around economic news.
That's why a “from 0.0 pips” headline is misleading on its own — it's the best case on a raw-spread account with a commission added on top. What matters is the typical spread on the instruments and at the times you actually trade.
How to compare spreads fairly
Look at average (not minimum) spreads on your main pairs, and remember to add commission on raw/ECN accounts. A 0.1-pip spread plus a $7 round-turn commission may cost more or less than a 1.2-pip all-in spread depending on your position size — do the math for your typical lot size.
Our comparison pages and cost breakdowns line brokers up on the same criteria so you're not comparing a best-case number against an average one.