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Common Forex Mistakes

How Does Ignoring the Spread Destroy Forex Profitability?

Pomegra Learn

How Does Ignoring the Spread Destroy Forex Profitability?

The bid-ask spread is the most underestimated cost in forex trading. A trader backtests a strategy that shows 50 pips of profit per trade, declares themselves a genius, and begins live trading. Three months later, they are confused to find that live profits are 30 pips per trade—and some months even negative. The culprit is not that the strategy failed. The culprit is that the trader ignored the spread in their analysis. The spread is not a minor "rounding error" that can be overlooked; it is the single largest friction cost in forex, and ignoring trading costs means systematically losing 30–60% of your expected profits. This article explains how spreads are calculated, why they widen during critical trading windows, how broker fees destroy an otherwise sound strategy, and how professional traders design strategies that survive—and profit—despite the spread tax.

Quick definition: The spread is the difference between the bid price (sell) and ask price (buy) for a currency pair; it is the cost you pay to enter a trade, regardless of whether the trade wins or loses.

Key takeaways​

  • The spread is not a fee you pay once; it is paid on entry and exit, doubling your cost per trade
  • A 1.5-pip spread on 100 trades per month = 150 pips lost per month to trading costs before commissions
  • Backtesting results that ignore the spread are fiction; live results that include spreads are reality
  • Spreads widen during volatility, economic news, and low-liquidity sessions—exactly when traders want to trade the most
  • A strategy with positive expectancy can become negative if its pip profit target does not exceed the spread cost by a 2:1 margin

The True Cost of the Spread​

The spread has two components: the cost on entry and the cost on exit. When a trader enters at the ask price (to go long) and exits at the bid price (to lock in gains), they pay the spread twice—once on entry and once on exit. This is routinely omitted from backtesting and analysis.

Real example: EUR/USD is trading at 1.0850 bid / 1.0851 ask (a 1-pip spread). A trader enters a long position at 1.0851 (the ask). For this trade to break even, the price must rise to 1.0852 (1 pip of gain) just to offset the spread cost on entry. If the trader exits at 1.0851 (the current ask), they have made 1 pip gross but paid 1 pip in spread on exit, resulting in zero profit. To make 20 pips of profit net, the price must move 22 pips: 1 pip to cover entry spread + 20 pips profit + 1 pip to cover exit spread.

Suppose a trader backtests without spreads and calculates that a mean-reversion strategy wins 40 pips on average. In live trading, those 40 pips become 40 – 2 – 2 = 36 pips (after spread costs on entry and exit). If the trader executes 100 trades per month, the annual spread cost is 400 pips × 12 = 4,800 pips per year. On a standard lot, that is $4,800 annually—a non-trivial cost that most traders ignore entirely.

How Spreads Expand During Critical Trading Windows​

A broker quotes EUR/USD at 1.0850 bid / 1.0851 ask (1 pip spread) during normal market hours. But spreads are not fixed. During these high-risk windows, spreads widen dramatically:

  • Economic data releases: 2–4 pips for major pairs
  • Central bank decisions: 3–6 pips
  • Asian open (11 PM–1 AM UTC): 1.5–2.5 pips
  • Pre-open gaps (Friday 4 PM ET): 2–3 pips
  • Volatility spikes: 2–5 pips

Real example: A trader observes that their strategy works best during the London open (8 AM UTC), when volatility is high and breakouts are common. They backtest during this window assuming a 1.5-pip spread (normal for European hours). When they trade live during the London open, they discover that the actual spread is 2.5–3.5 pips, and slippage adds another 0.5 pips. Their effective cost per trade is 4 pips, not 1.5 pips. On 80 trades per month (5 per trading day during London open), this is 320 pips in spread costs, or $3,200 annually per standard lot.

The solution is to backtest using the actual spread costs that occur during your intended trading window. If you trade during the London open, use 3-pip spreads in your backtest. If you trade around economic releases, use 4-pip spreads. Ignoring this adjustment means your backtest is disconnected from reality.

Cost-spread interplay flowchart​

The Broker Selection Factor​

Not all brokers charge the same spread. There are several broker types:

  • Market makers: Fixed spreads (usually 1.5–3 pips), no commission, but the broker profits when you lose
  • STP brokers: Variable spreads (0.5–2.5 pips depending on market conditions), plus $2–5 per round-turn trade
  • ECN brokers: Very tight spreads (0.1–1 pip), plus higher commission ($5–10 per round-turn trade)

A trader ignoring trading costs might choose a market maker with a fixed 1.5-pip spread, thinking it is cheaper than an ECN broker's 0.3-pip spread plus $8 commission. In reality, they are paying 150 pips per month in spreads (assuming 100 trades), which is $1,500 annually, versus the ECN trader's 30 pips in spreads plus $800 in commissions = $830 annually. The ECN trader saves $670 per year per standard lot—and crucially, the ECN trader is not trading against a broker that profits when they lose.

Real example: A trader maintains a $5,000 account and executes 5 trades per week (20 per month, 240 annually).

  • Broker A (market maker, 2-pip spread): 240 trades × 2 pips × 2 (entry and exit) = 960 pips = $960 annually
  • Broker B (ECN, 0.5-pip spread, $5 commission): (240 trades × 0.5 pips × 2) + (240 × $5) = 240 pips ($240) + $1,200 = $1,440 annually

In this case, Broker A appears cheaper because the high volume makes commissions expensive. But Broker A is a market maker, which creates a different problem: conflict of interest. When you win, the broker loses. This incentivizes Broker A to widen spreads during volatile trading, slow down order execution, or otherwise disadvantage you. Broker B has no such incentive because it profits regardless of your outcome.

Designing Strategies That Survive the Spread​

The solution is to build the spread cost into your strategy design from the beginning. A strategy with 1:2 risk-reward (risking 30 pips to win 60 pips) is mathematically superior to a strategy with 1:1 risk-reward, but only if your win rate is above 33%. Once you subtract the spread, the effective profit target is reduced.

Real model: A trader backtests a strategy with these parameters:

  • Entry setup: 20-day moving average breakout
  • Average profit target: 50 pips
  • Average stop-loss: 25 pips
  • Win rate: 45%
  • Spread cost: 2 pips per round-turn (1 pip entry, 1 pip exit)

Theoretical profit per trade:

  • 45% × 50 pips (wins) – 55% × 25 pips (losses) = 22.5 – 13.75 = 8.75 pips per trade

Real profit per trade (including spread):

  • 45% × (50 – 2) pips – 55% × (25 + 2) pips = 45% × 48 – 55% × 27 = 21.6 – 14.85 = 6.75 pips per trade

The spread reduces profit by 23% (from 8.75 to 6.75 pips). On 100 trades per month, the annual spread tax is 200 pips per standard lot, or $2,000. Over 10 standard lots, that is $20,000 per year lost purely to trading costs.

To offset this, the trader can:

  1. Increase the profit target: Change the target from 50 pips to 60 pips (a 20% increase)
  2. Reduce the stop-loss: Change the stop from 25 pips to 20 pips (a 20% reduction)
  3. Trade only during low-spread windows: Limit trading to high-liquidity hours when spreads are tightest
  4. Reduce trade frequency: Execute 50 high-conviction trades per month instead of 100 mediocre trades

Option 4 deserves emphasis because it is the most underutilized. A trader who executes 50 trades per month with a 50-pip average profit target has a spread cost of 100 pips. A trader who executes 100 trades per month with a 50-pip target has a spread cost of 200 pips—double. But the second trader's total profit is not double; it is increased by only 30–40% because the marginal win rate on additional trades declines as setup quality deteriorates. Trading less and trading better is the professional approach to spread-cost management.

Comparing Backtested Results to Live Reality​

A trader backtests a strategy on TradingView or MetaTrader and obtains these results:

  • 100 trades
  • 50 wins, 50 losses
  • Average win: 35 pips
  • Average loss: 25 pips
  • Gross profit: (50 × 35) – (50 × 25) = 1,750 – 1,250 = 500 pips

The trader then trades live and obtains these results:

  • 100 trades
  • 50 wins, 50 losses
  • Average win: 33 pips (after spread on exit)
  • Average loss: 27 pips (after spread on entry)
  • Net profit: (50 × 33) – (50 × 27) = 1,650 – 1,350 = 300 pips

The discrepancy (500 backtested vs. 300 live) is entirely attributable to the spread being ignored in the backtest. Many traders interpret this 40% reduction as a sign that their strategy is flawed or that live market conditions are worse than historical conditions. In reality, they simply failed to account for trading costs.

The fix is to add realistic spread and commission assumptions to every backtest:

  • Backtest with a 2-pip spread cost (1 pip on entry, 1 pip on exit) if you trade during normal hours
  • Backtest with a 4-pip spread cost if you trade around economic news
  • Add commissions if using an ECN broker
  • Add slippage (0.3–1 pip) if your account size is large

Real-World Examples​

Case 1: The Scalper's Spread Problem A day trader developed a scalping strategy that aimed for 10 pips of profit per trade. They backtested across 12 months of data and found a 60% win rate with an average win of 12 pips and an average loss of 8 pips. Live performance: (60% × 12) – (40% × 8) = 7.2 – 3.2 = 4 pips per trade. But the actual spread on their broker (a market maker) was 1.5 pips per round-turn, meaning actual profit was 4 – 1.5 = 2.5 pips per trade. On 50 trades per day (8 trading hours × 6 trades per hour), this is 125 pips per day. Gross annual profit (250 trading days): 31,250 pips, or $31,250. Then they switched to an ECN broker with 0.3-pip spreads and $2 commission per round-turn. The effective cost dropped to 0.6 + 2 = 2.6 pips per trade, and their profit per trade rose to 1.4 pips. On 50 trades per day, this is 70 pips per day, or $17,500 annually—56% less than the market maker. However, the advantage is that the ECN broker has no incentive to manipulate spreads against them, and execution is more reliable.

Case 2: The News-Release Blowup A fundamental trader built a strategy around interest-rate decisions and inflation announcements. During normal trading, EUR/USD had a 1.5-pip spread. The trader backtested assuming this 1.5-pip spread throughout, and the backtest showed a 3-pip average profit per trade. Live trading: when the actual news hit, the spread widened to 4 pips, instantly erasing the entire edge. The trader lost money on every news trade for three months before realizing that backtesting during normal conditions but trading during high-volatility conditions was the root cause. The solution was to either avoid trading around news, or to rebuild the strategy to work with a 4–5 pip spread cost (requiring 10+ pip average profits to break even).

Common Mistakes​

  1. Backtesting without spreads: A strategy backtested without spread costs will show 30–50% better results than live trading. This is not your strategy working better in the past; it is your analysis ignoring costs.

  2. Ignoring the spread on exit: Traders often account for the spread on entry but forget that they pay it again on exit. The true round-trip cost is double the quoted spread.

  3. Trading during wide-spread windows: Scalpers trading during Asian hours and around economic releases are paying 3–4x the typical spread cost, destroying the profit potential of their otherwise viable strategy.

  4. Choosing the wrong broker type: A trader with a high-volume, low-profit-margin strategy (scalping or day trading) should use an ECN broker despite commissions. A trader with a lower-volume, high-profit-margin strategy (swing trading or position trading) can use a market maker.

  5. Assuming spreads are symmetric: Brokers often offer tight spreads on major pairs (EUR/USD, GBP/USD) but wide spreads on exotic pairs (USD/ZAR, AUD/NZD). Trading exotics with the same frequency as majors will destroy profitability due to spread costs alone.

FAQ​

What is a reasonable spread to assume when backtesting?​

For major pairs during normal market hours: 1.5–2 pips. For economic releases: 3–4 pips. For Asian hours: 2–2.5 pips. For exotic pairs: 3–5 pips. Always backtest with the spread that reflects when you actually trade.

Should I include commission in my backtest if I use an ECN broker?​

Yes. The commission is a real cost. A $5 commission per round-turn on a $10,000 account executing 10 trades per month is $500 in annual commission, which is 5% of your account. It must be modeled.

How much of my strategy's profit comes from the spread, and how much from skill?​

Calculate it: gross profit per trade (no spread) minus net profit per trade (with spread) = spread cost per trade. If your gross profit is 8 pips and your net profit is 5 pips, then 3 pips come from skill and 3 pips are erased by the spread. This reveals whether your strategy's edge is real or illusory.

Can I avoid the spread by trading only the most liquid pairs?​

Partially. Major pairs (EUR/USD, GBP/USD, USD/JPY) have the tightest spreads during liquid hours. But you cannot eliminate spread costs; you can only minimize them. The difference between a 1-pip spread (best case) and a 2-pip spread (normal case) is often the difference between profitable and unprofitable trading.

What is the impact of spread on a high-leverage account?​

Spread impact is proportional to lot size. A 1.5-pip spread costs $15 per standard lot, $1.50 per micro lot. If you are using high leverage and trading 10 standard lots per trade, the spread cost is $150 per trade. Over 100 trades per month, that is $15,000 in spread costs—15% of a $100,000 account. High leverage makes spread costs catastrophic.

Is there a broker that offers zero spreads?​

No legitimate broker offers zero spreads. Brokers profit either from spreads or commissions (or both). Any broker claiming "zero spreads" is either a market maker taking the other side of your trades (conflict of interest) or is hiding commissions elsewhere.

How do I know if a broker is widening spreads against me?​

Compare the spread you see in your trading platform to the spread quoted on multiple other platforms or broker websites. If your spreads are consistently 0.5–1 pip wider than other brokers on the same pair at the same time, you may be using a market maker that is widening spreads against you.

Summary​

Ignoring the spread means systematically underestimating your trading costs and overestimating your strategy's profitability. A strategy that shows 8 pips of profit per trade in a backtest that excludes spreads will show 5 pips of profit in live trading that includes spreads. The 37% reduction is not because the market changed or your skill declined; it is because you ignored a fundamental cost. Professional traders design strategies with spread costs built in from the first backtest. They trade during low-spread windows, they trade high-conviction setups rather than high-frequency setups, and they choose brokers aligned with their trade frequency. A trader who acknowledges spread costs and designs around them will consistently outperform a trader who ignores them and discovers the gap between backtested and live results only after losing money.

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