Why Traders Must Understand Daily Gain/Loss Volatility and How to Use It to Forecast Portfolio Swings

Many people look only at gain % or maximum drawdown of a trading system, but forget that along the way from point A to point B, how much does our portfolio swing each day? Some make 20% profit per month, but in exchange for days when the portfolio jumps 5% then plunges 7% the next day, causing panic and withdrawals before the system reaches its target. This is why traders must understand Daily Gain/Loss Volatility—the volatility of daily gains and losses—to mentally prepare and manage risk in line with their own psychological tolerance.

What Is Daily Gain/Loss Volatility

Daily Gain/Loss Volatility measures the volatility of daily profit and loss in our trading account. Typically, the Standard Deviation of daily returns is used as the indicator. The higher the value, the more violently our portfolio swings up and down each day. The lower the value, the smoother the portfolio movement.

Example: Traders A and B both make 15% profit in the same month. But Trader A has a daily volatility of 0.8% per day, whilst Trader B has a daily volatility of 3.5% per day. This means Trader B experiences portfolio swings nearly 4 times more violent, even though the final result is the same.

Why Traders Must Care About Daily Volatility

1. Helps Assess Hidden Risk

Metrics like Sharpe Ratio or Calmar Ratio tell us whether returns are worth the risk, but they don't tell us how much volatility we must endure along the way. If you open an account with 100,000 baht and find that daily volatility is 2%, that means on a normal day your portfolio may swing about 2,000 baht, and on abnormal days (2 standard deviations) it could reach 4,000 baht.

2. Prevents Emotional Decision-Making

Most traders abandon good trading systems because they aren't mentally prepared for daily volatility. They see the portfolio plunge 5% in one day, think the system is broken, close orders and cut losses, then the next day the system rebounds with 7% profit—but we're no longer in the game. Knowing the daily volatility in advance lets us expect which days the portfolio might plunge or surge and not panic.

3. Helps Choose a Trading System That Fits Your Personality

People with high volatility tolerance may choose systems that use high leverage, trade frequently, and have daily volatility of 3-5% in exchange for higher returns. But people who can't sleep when they see the portfolio drop 2% should choose systems with daily volatility below 1%. Even if returns are lower, consistency and mental health are better.

How to Calculate and Interpret Daily Gain/Loss Volatility

Simple Calculation Method

1. Pull daily profit-loss data (% change of equity each day) for at least the past 30-90 days
2. Calculate the Standard Deviation of those daily returns
3. The resulting value is your daily volatility

If you use a platform like Thaifxbook, the system will calculate and display this value automatically, along with a graph showing the distribution of daily returns, giving you a clear picture of how much your portfolio swings each day.

Interpreting Daily Volatility Values

• Below 0.5% per day: Very smooth trading system, suitable for people who want stability and low risk
• 0.5-1.5% per day: Moderate level, suitable for average traders who want balance between risk and return
• 1.5-3% per day: High level, suitable for experienced traders with good volatility tolerance
• Above 3% per day: Extreme level, often found in scalping systems or systems using very high leverage. Must be especially careful about Psychological Drawdown

How to Use Daily Volatility to Adjust Trading Strategy

1. Set Appropriate Position Size

If you find daily volatility is too high, it means you may be opening lots that are too large. Try reducing lot size by 30-50% and observe whether daily volatility decreases. The goal is to find the balance where you can sleep comfortably but still get satisfactory returns.

2. Set Daily Loss Limits

If you know your daily volatility is 1.5%, you can set a rule that if any day losses exceed 2x daily volatility (3%), stop trading that day immediately. This means that day is abnormal. Continuing to trade increases the chance of heavier losses because emotions interfere.

3. Compare with Other Traders

On Thaifxbook you can view other traders' profiles and compare their daily volatility with yours. If someone with similar profits has much lower daily volatility than you, it means they have better risk management efficiency and you should study their strategy.

Common Mistakes Traders Make Regarding Daily Volatility

1. Looking Only at Total Returns, Ignoring Volatility Along the Way

Many people see a trading system make 50% profit per year and jump in immediately, without knowing that along the way the portfolio swings 5-10% per day. When they encounter real volatility, they panic and close the system before achieving that 50% profit.

2. Not Adjusting Volatility for Time Periods

Daily volatility is not a fixed number. During periods of major news or economic crisis, volatility will spike. Traders must monitor and adjust strategy accordingly, such as reducing lot size during periods of abnormally high volatility.

3. Comparing with Others Without Considering Timeframe

A scalper who trades 50 times per day versus a swing trader who holds orders across weeks will have very different daily volatility. Comparisons must consider the context of trading frequency and holding time as well.

Tools to Monitor Daily Volatility

Platforms like Thaifxbook connect to your MT5 account and display daily volatility statistics in real-time, along with graphs showing the distribution of daily returns. You can see immediately how much your portfolio has swung over the past 30-90 days, which days were outliers (abnormal), and when you should be cautious.

Additionally, you can set alerts when daily volatility spikes above your defined threshold, to remind you to adjust strategy or reduce risk immediately, before volatility destroys your portfolio.

Summary

Daily Gain/Loss Volatility is a metric professional traders use to assess how much our portfolio must swing along the way to our goal. Knowing this value in advance helps us mentally prepare, adjust strategy, and choose a trading system that fits our personality, rather than looking only at final profit figures and panicking midway when encountering unexpected volatility.

Remember that sustainable trading isn't just about chasing maximum returns, but finding balance between returns, risk, and our mental health. And daily volatility is a crucial tool to help you achieve that balance.