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How to backtest a trading strategy, step by step

Imagine testing your rules on 100 trades before you risk a cent. That's backtesting: replaying past charts by hand. It's free, and it trains your eye too.

Beginner guide · 9-minute read · Updated 2026-10-21

What backtesting is

Backtesting is testing a set of trading rules on past price data. You go back in time, follow your rules exactly, and write down what each trade would have done.

There are two kinds:

• Automatic: a computer runs coded rules over years of data.
• Manual: you move through a past chart one candle at a time and make each decision yourself.

This guide is about the manual kind. It's slower, but for a beginner it's better: you're not just testing the rules, you're practicing seeing them.

Step 1: Write your rules down first

You can't test a strategy that lives in your head. Before you open a chart, write rules that someone else could follow without asking you questions.

• Market and timeframe: which chart, which time frame.
• Direction: how you decide whether to look for buys or sells (for example, from the bigger chart's trend).
• Entry: the exact thing that must happen. One sentence.
• Stop: where it goes — for example, just past the last turning point.
• Target: where it goes — for example, the next level price turned at, at least 2-to-1.
• Skip rules: when you don't trade.

The test for a good rule: two people reading it on the same chart would take the same trade. If they'd argue, the rule isn't clear enough yet.

A one-page trading plan is a good place to put these.

Step 2: Set up replay on TradingView

TradingView has a Bar Replay tool. You pick a date in the past, and the chart hides everything after it. Then you step forward one candle at a time.

1. Open your chart and time frame.
2. Click Replay in the top toolbar.
3. Click a point in the past to start from.
4. Use the step-forward button to reveal one candle at a time.

Full walkthrough: TradingView bar replay. Replay features can vary by plan, so check what your account includes.

Step 3: Never peek

This is the rule that makes or breaks a backtest. Don't look at what happens next before you decide.

If you scroll ahead, or you already remember this chart, your brain will "find" the trades that worked and skip the ones that didn't. The results will look great and mean nothing.

• Pick a start date you don't remember.
• Make the decision, write it down, then step forward.
• If you accidentally see the future, skip that stretch.

Step 4: Log every trade, including the ugly ones

Each trade gets a row, even the ones you'd rather forget. Track at least:

• Date on the chart, and market.
• Long or short.
• Entry, stop and target.
• Result in units of risk (−1 at the stop, +2 at a 1:2 target).
• Did I follow my rules? Yes or no.

A trading journal works for this. Our free journal template has the columns ready.

Step 5: Do 100 trades

Ten trades tell you almost nothing. A few lucky ones can make a bad rule look good, and a few unlucky ones can make a good rule look bad.

Aim for 100 trades before drawing conclusions. That's enough to see the shape of the results. Spread them over different months and market moods: some trending, some choppy.

It sounds like a lot. Done in replay, many traders get through 10–20 a session.

Step 6: Measure what matters

When you have your trades, work out:

Expectancy is the headline number: (win rate × average win) − (loss rate × average loss).

Plug your own numbers into the expectancy calculator.

Common backtesting mistakes

• Changing the rules halfway. If you change a rule, start a new test from trade 1.
• Peeking. The most common one, and it ruins everything.
• Testing only the good-looking charts. Use whatever comes next.
• Ignoring costs. Spreads and commissions shave every trade a little.
• Treating a backtest as proof. It's evidence, not a guarantee.

What comes after

A backtest answers "do these rules hold up on the past?" The next step is real time with no money at stake: paper trading. Then, if you choose, very small live size. Each step tests the same rules under a little more pressure.

Try it today

1. Write your entry rule in one sentence.
2. Open a daily chart in replay, starting a year back.
3. Take 10 trades without peeking. Log every one.
4. Count how many followed your rules exactly.

Questions