Forex

How to Calculate the Forex Spread: Formula and Examples

Astron Team · 09/24/2026 · 4 min read

To calculate the forex spread, simply subtract the buy price (bid) from the sell price (ask) and convert that difference into pips. If EUR/USD is quoted at 1.08500 on the sell side and 1.08512 on the buy side, the spread is 0.00012, or 1.2 pips. If the pip value in that trade is R$ 10, that spread costs about R$ 12 just to enter and exit the trade.

That's the easy part of the math. The part the trader feels afterward is what the spread does to a small target, a tight stop, or a strategy that trades too frequently.

First step: calculate the spread in pips

The spread is the difference between the sell price (bid) and the buy price (ask):

Spread = buy price − sell price

For most major pairs, one pip equals 0.0001. For pairs with the Japanese yen, one pip equals 0.01. Example with EUR/USD: sell price at 1.08500, buy price at 1.08512. The difference is 0.00012, which equals 1.2 pips.

A buy trade normally opens at the buy price and closes at the sell price; a sell trade does the reverse. This difference between the two prices is one of the quiet ways the cost of trading shows up — the trade already starts slightly negative, and it's easy to get used to seeing that without realizing it remains a real cost on every entry.

Second step: turn the spread into money

Once you know the spread in pips, calculating the cost in money is straightforward:

Spread cost = spread in pips × pip value

If the spread is 1.5 pips and the pip value is R$ 10, the estimated cost is:

1.5 × R$ 10 = R$ 15 per trade

Over twenty similar trades in a month, that cost climbs to R$ 300. The math is simple — the hard part is remembering to do it before getting attached to a strategy that relies on small targets.

Why position size changes everything

The spread is measured in pips, but paid in money — which means the same 1.5-pip spread can be irrelevant or expensive, depending on the position size:

• 0.01 lot (pip value of about R$ 0.50) — a 0.8-pip spread costs R$ 0.40; a 1.5-pip spread costs R$ 0.75; a 2.5-pip spread costs R$ 1.25.
• 0.10 lot (pip value of about R$ 5.00) — the same spreads cost R$ 4.00, R$ 7.50, and R$ 12.50.
• 1 standard lot (pip value of about R$ 50.00) — the same spreads cost R$ 40.00, R$ 75.00, and R$ 125.00.

Saying only "the spread is 1 pip" is incomplete information. One pip on 0.01 lot of EUR/USD is worth about R$ 0.50; the same pip on 1 standard lot is worth about R$ 50. Anyone trading large positions or at high frequency can't treat the spread as background noise.

The spread's cost as a percentage of the target

The more useful comparison isn't "how many pips is the spread", but "how much of my planned target does the spread represent". If a trade's target is 5 pips and the spread is 1 pip, the spread already eats up 20% of the gross target before the price even moves in the trade's favor.

This problem is more visible for very short-term traders, but isn't limited to them. A trader who enters several times in the same session can see a small spread on a single trade become significant over a full week of trading. Meanwhile, someone trading larger swing-trade targets feels the spread less per trade, but still needs to compare the cost across different pairs — an exotic pair with a wide spread can make a technically good setup much less attractive in practice.

A complete example, start to finish

A trader with a R$ 5,000 account trades 0.20 lot of EUR/USD (pip value of about R$ 2), with a 1.4-pip spread and a 40-pip target. The spread cost is:

1.4 × R$ 2 = R$ 2.80 per trade

Compared to the gross target of 40 pips, equivalent to R$ 80, the spread represents 3.5% of the target — a manageable cost. The same trader, going for a scalping target of just 6 pips (R$ 12), would see the spread eat up about 23% of the gross target — a much more significant chunk, requiring a higher win rate just to offset the cost of trading.

The habit that avoids surprises in the result

Before adopting any strategy based on small targets, it's worth calculating the spread in pips for the chosen pair, converting it into money at the planned position size, and comparing that amount with the trade's target. If the spread eats up a small slice of the target, the cost is reasonable. If it eats up a large slice, the strategy may be competing against the cost of trading itself before even considering market risk. This simple calculation, done on Astron or any other platform before confirming the order, helps you understand whether a strategy is truly viable or whether the spread alone already undermines the expected result.