How to Build a Web-Based Trading Journal and Performance Calculator

Last checked: 12 October 2026. This guide explains standard performance metrics and a simple browser-only design. It is educational and is not financial advice.

A trading journal records every trade so you can learn from what you actually did instead of what you remember. A web-based journal is easy to build with plain HTML and JavaScript, and it can calculate the numbers that matter: win rate, average win and loss, profit factor, expectancy and maximum drawdown. This guide explains each metric and how to build a small journal that runs entirely in the browser.

What to record for each trade

• Date and time, symbol and direction (buy or sell).
• Entry price, stop loss and exit price.
• Lot size and the money result after costs.
• The reason for the trade and the setup name.
• A short note on how you felt and whether you followed your plan.

The last two fields are the ones most traders skip and the ones that teach the most. A trade that lost money while following your rules is different from one that lost because you broke them.

The core metrics

Let a “win” be a trade with a positive result and a “loss” be a negative one.

• Win rate = winning trades divided by total trades.
• Average win = total profit of winners divided by the number of winners. Average loss is the same for losers, taken as a positive number.
• Profit factor = total profit of winners divided by the total loss of losers. Above 1 means gross profits exceeded gross losses.
• Expectancy per trade = (win rate × average win) minus (loss rate × average loss). It is the average amount you gained or lost per trade.
• Maximum drawdown = the largest fall from a peak in your running balance to a later low.

Why win rate alone misleads

A trader who wins 70 percent of trades but loses three times as much on each loser can still lose money. Another who wins 35 percent but makes three times as much on each winner can profit. Expectancy and profit factor combine win rate with size, which is why they matter more.

A minimal browser calculator

The function below takes an array of trade results (positive or negative numbers) and returns the metrics. It can be placed inside a script tag in a web page or in an HTML artifact.

function analyse(results, startBalance) {
  const n = results.length;
  if (n === 0) return null;

  const wins   = results.filter(r => r > 0);
  const losses = results.filter(r => r < 0);
  const grossWin  = wins.reduce((a, b) => a + b, 0);
  const grossLoss = Math.abs(losses.reduce((a, b) => a + b, 0));

  const winRate  = wins.length / n;
  const avgWin   = wins.length   ? grossWin / wins.length : 0;
  const avgLoss  = losses.length ? grossLoss / losses.length : 0;
  const expectancy = winRate * avgWin - (1 - winRate) * avgLoss;
  const profitFactor = grossLoss === 0 ? Infinity : grossWin / grossLoss;

  // maximum drawdown from the running balance
  let balance = startBalance, peak = startBalance, maxDD = 0;
  for (const r of results) {
    balance += r;
    if (balance > peak) peak = balance;
    const dd = (peak - balance) / peak;
    if (dd > maxDD) maxDD = dd;
  }

  return { trades: n, winRate, avgWin, avgLoss, expectancy,
           profitFactor, maxDrawdownPct: maxDD * 100,
           endBalance: balance };
}

// Example
console.log(analyse([120, -60, 80, -60, -60, 200, 40, -60], 1000));

Treat breakeven trades (a result of exactly zero) as neither win nor loss. If you prefer to count them, change the filters, but be consistent.

Storing the data

A simple journal can keep trades in the browser’s localStorage so they survive a refresh. Wrap reads and writes in try and catch, because storage can be disabled or full. Browser storage (localStorage) is private to that browser on that device, so it will not sync to your phone, and clearing browser data deletes it. Provide an Export button that downloads your trades as a CSV file, and keep a backup. If your journal is hosted on a public site, do not send trade data to a server unless you understand the privacy implications.

Importing from MetaTrader 5

In the terminal’s History tab you can right-click and choose Report to save results as HTML or CSV. You can then paste the profit column into your journal. Check that you use net profit, including commission and swap, otherwise the numbers will look better than reality.

How to review

1. Once a week, read your notes and tag trades as “followed plan” or “broke plan”.
2. Compare the expectancy of the two groups. Many traders find their rule-breaking trades are the ones that hurt.
3. Look at the largest loss. Was it within your risk limit?
4. Change one thing at a time and track whether the metrics improve over the next fifty trades.

Limits

• With few trades, all metrics are noisy. Twenty trades say very little.
• Metrics describe the past and do not predict the future.
• Honest journalling depends on recording losing trades too.

What we could not confirm

• What counts as a “good” profit factor. Commonly quoted thresholds vary and are opinions, not standards.
• How your broker reports swap and commission in exported reports.

Frequently asked questions

Can I use a spreadsheet instead? Yes. The same formulas work in any spreadsheet, and a web page just makes it more convenient.

Is a web journal safe for my data? If it runs only in your browser and stores nothing on a server, your trades stay on your device. Always export backups.

Key takeaways

Record what you did and why, calculate expectancy and drawdown rather than relying on win rate, keep backups and review your behaviour, not just your results.

Sources checked

• General trading-statistics definitions (win rate, profit factor, expectancy, drawdown). These are standard formulas rather than a single published source, so verify them against your own platform’s report.