Fundamentals6 min read

What Is Backtesting?

Backtesting means running a trading strategy against historical price data to see what would have happened. It's the difference between guessing a strategy works and knowing what it would have done over the past year.

Why Backtesting Matters

Most retail CFD traders lose money. The standard industry disclosure says 70-80% of retail accounts lose money when trading CFDs. There are many reasons for this, but one of the biggest is simple: they never tested their strategy.

You wouldn't buy a car without knowing if it runs. You wouldn't invest in a business without seeing the financials. Yet most traders risk real money on strategies they've never seen tested against historical data.

Backtesting doesn't guarantee future results — markets change, and past performance is just that. But it gives you a baseline. If your strategy lost money every month for the past year, that's a signal. If it was profitable with a 40% win rate and a 1.8 profit factor, that's a different signal.

How Backtesting Works

The process is straightforward:

Choose a strategy. Pick your entry and exit rules — which indicators, what thresholds, what conditions.

Select an instrument. Forex pair, index, commodity, stock — whatever you plan to trade.

Set risk parameters. Stop-loss, take-profit, trailing stop, risk percentage per trade.

Run the backtest. The engine walks through historical data bar by bar, executes trades based on your rules, and records every result.

Read the statistics. Win rate, total P/L, Sharpe ratio, profit factor, max drawdown, and every individual trade.

What the Numbers Mean

Win Rate — Percentage of trades that were profitable. 50% means half your trades won. Alone, this tells you nothing — a 90% win rate with tiny wins and huge losses is still losing money.

Profit Factor — Gross profit divided by gross loss. Above 1.0 means profitable. Above 1.5 is solid. Above 2.0 is excellent. This matters more than win rate.

Sharpe Ratio — Risk-adjusted return. Above 1.0 is good, above 2.0 is excellent. Measures how much return you get per unit of risk taken.

Max Drawdown — The largest peak-to-trough decline in your equity curve. If your account went from $10,000 to $6,000, that's a 40% drawdown. This is the number that tells you whether you can stomach the strategy emotionally.

What Backtesting Can't Do

Backtesting has hard limitations. It does not account for:

✗ Slippage — the difference between expected price and actual fill price
✗ Spread widening — spreads can blow out during news events or low liquidity
✗ Liquidity gaps — price gaps where no trades can be executed
✗ Real-world execution — requotes, order rejection, platform downtime

A strategy that looks perfect in backtesting can still lose money in live trading. The point of backtesting is not to find a guaranteed winner — it's to eliminate strategies that don't work and understand the ones that might.

Start Backtesting

You can test any of 5 strategies across 50+ instruments right now on the backtester — no login, no signup. Or browse the Strategy Lab to see the top-performing setups from 1,200 nightly backtests.

→ The Honest Truth About Backtesting → Win Rate vs Profit Factor → Monte Carlo Simulation

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