Backtesting, when applied correctly, can be very effective in assessing the power of your trading strategy. This is true only if the parameters used for backtesting match the market conditions. One of the factors that considerably impacts the backtest accuracy is the spread, which is the difference between the buying price and the selling price.
Many traders in MetaTrader 5 (MT5) completely ignore the spread setting or unknowingly test with unrealistically low spreads. The outcome is that they are getting backtests that look profitable in theory, but lose heavily in reality.
To do this, you must modify and optimise the spread settings in the MT5 Strategy Tester. The full, lengthened guide below covers everything you need to understand.
Why Spread in MT5 Backtesting Affects Accuracy and Common Trader Mistakes
The spread is the factor that almost changes everything in your strategy:
- The entry price for a buy order is the ask, and for a sell order is the bid. Ignoring spreads may cause early stop-loss triggers or unrealistically profitable trades.
- An early trigger is likely to occur at your stop-loss.
- A small margin might not reach your take-profit.
- Scalping and EA strategies can look profitable with ideal spreads but fail in the live markets.
The MT5 platform, if you do not set the spread manually, may default to a near-zero or very tight value, which is quite unrealistic, especially for historical data. This situation leads to a false sense of accuracy, where the traders might think their strategy is stronger than it actually is.
The high accuracy with spread simulation is a must for:
- Prop firm EA testing
- Scalping systems
- Grid and martingale EAs
- News-based strategies
- High-frequency or high-trade-volume systems
If your ambition is to achieve the reliability, consistency, and funding challenges, this step must not be avoided.
Step 1: Open the Strategy Tester Panel
Get MetaTrader 5 running. Open the Strategy Tester by either using the Ctrl + R shortcut or clicking it on the bottom bar.
Pick the EA you want to test, the currency pair, the timeframe, and the testing method (for example, ‘Every Tick’ for maximum accuracy). This is the main panel for all the settings needed for backtesting.
Step 2: Find and Modify the Spread Setting
On the right side of the Strategy Tester:
- Check out the field for Spread.
- The typical setting is Current, which takes the spread then, but just for the opening price, not for historical accuracy.
- Switch it over to “Points”.
- Put in a real spread number that applies to your broker.
Realistic Spread Inputs Examples:
- EURUSD → 10–20 points (1.0–2.0 pips)
- XAUUSD → 200–400 points (20–40 pips, depending on broker/market volatility)
- GBPUSD → 20–30 points (2–3 pips)Â
Note: Spreads vary by broker and account type, so check your broker’s historical data.
By manually setting the spread, you guarantee that the backtest is in line with actual execution conditions.
Step 3: Use Historical Spread (When Available)
If your broker provides this feature, the spread on MT5 will correspond to the historical dates you are testing.
To do this:
Select Use Date and indicate your testing timeframe.
Set the Spread to Current.
In case the broker supplies historical bid and ask data, MT5 will calculate realistic spreads throughout the entire testing period. The method is useful for testing:
- Days with high volatility
- Intervals reflecting abnormal market activity
- Weekends and rollover spreads
- Nonetheless, not all brokers provide complete historical spread data, so always check for accuracy.
Step 4: Simulate Variable Spreads Using Tick Data
When you are using external tick data (Dukascopy or custom imports), spreads will usually change automatically since both bid and ask data are included.
To make the variable spread simulation work:
- Upload tick data containing both bid and ask values.
- Set Spread = 0.
- MT5 will use the bid/ask data from your tick file to simulate variable spreads, giving the most realistic backtest possible.
- This technique works best for EA developers and prop firm testers.
Step 5: Re-Test After Adjusting Spread
Once you have input your desired spread value:
Hit Start to start the test.
Look into:
- Equity curve
- Changes in win-rate
- Behaviour of stop-loss
- Differences in drawdown
- Changes in profit factorÂ
Changing the spread often brings to light weaknesses that were not discovered in tests done with zero spread. A strategy that is only effective with ultra-tight spreads is not strong enough for live markets.
Step 6: Stress-Test the Strategy With Multiple Spread Levels
A reliable strategy must endure under different environmental conditions.
Simulate testing with:
- Low spread: 5–10 points
- Normal spread: 15–25 points
- High spread: 30–50 points
This way, you can find out if your EA is:
- Spread-sensitive (not good for prop firms)
- Very robust (suitable for long-term trading)
- Scalping-dependent (needs ultra-low spreads + VPS)
A lot of losing EAs hit this step failing right away, so it’s one of the quickest methods to detect weak strategies.
How Trading FX VPS Enhances MT5 Backtesting and Live Execution
One of the major difficulties traders encounter is the inconsistency between backtest results and market performance. Assuming that your MT5 Strategy Tester is appropriately adjusted with the realistic spreads, the trades will still react differently under live conditions if there is an execution delay or instability. This is where Trading FX VPS becomes an essential component of a trader’s setup – especially for users of EAs, scalpers, and traders from prop firms who depend on very accurate order placement.
While backtesting accuracy depends on correct spread settings, using Trading FX VPS ensures that live execution reflects the conditions assumed in your backtest. This minimizes slippage and improves EA performance in live or forward-testing environments.
Trading FX VPS operates ultra-low-latency servers in major trading hubs such as Singapore, New York, and London, so your MT5 platform can interact with brokers in milliseconds. This is important since quicker execution results in:
- More accurate spread behaviour
- Lower slippage
- Better fill prices
- More consistent EA performance
- Smoother tick-by-tick data flow
A VPS also permits you to do numerous backtests and optimisations at once while tuning strategies in MT5’s Strategy Tester, which will not cause any slowdown of your personal computer. This will make EA development, forward testing, and optimisation very much more efficient.
For live trading, Trading FX VPS keeps your MT5 terminal online 24/7, no matter if your home internet is down or your computer is rebooting. This is crucial for strategies that need to achieve full uptime – especially grid systems, martingale EAs, news algorithms, and any method that includes pending orders.
When you match the proper MT5 spread simulation with a speedy, reliable VPS environment, you have closed the gap between historical results and real market performance. Trading FX VPS provides traders with a more controlled and predictable execution environment, thus making backtests more relevant, optimisations more accurate, and live trading more reliable.