ATR position sizing: volatility-based stops and lot size

What ATR measures

The Average True Range (ATR) is an indicator that measures how far price usually moves in a bar. For each bar it takes the "true range": the largest of the bar's high minus low, the high minus the previous close, and the low minus the previous close. It then averages these values over a chosen number of bars.

ATR is expressed in price units, such as pips on a currency pair or dollars on XAUUSD. It shows how much an instrument moves. It does not show direction. A rising ATR means bars are getting larger. A falling ATR means the market is quieter.

MetaTrader 4 and MetaTrader 5 both include ATR in their standard indicator list. You can change its period in the indicator settings.

Why use volatility position sizing

A fixed stop of the same pip distance on every instrument ignores how differently they move. A distance that suits a quiet currency pair may sit inside normal noise on gold or US100. On those instruments, normal price movement can hit the stop even when the trade idea has not failed.

ATR position sizing handles this in two parts:

1. The stop adapts to volatility. The stop distance is a multiple of the current ATR, so it is wider on fast instruments and tighter on slow ones.
2. The size adapts to the stop. The lot size is reduced when the stop is wider and increased when it is tighter. If the stop is hit, the loss in money stays roughly the same.

The goal is consistent risk per trade. Consistent risk does not make a strategy profitable. It keeps a single losing trade from being much larger than the others.

The method step by step

1. Choose your risk per trade. This is a fixed share of your balance. See Risk per trade for how traders think about this choice.
2. Read the current ATR on the timeframe you trade.
3. Pick an ATR multiple. Stop distance = ATR × multiple. A larger multiple gives the trade more room but needs a smaller position.
4. Find the money value of the stop for a single lot. This depends on the instrument's contract size and pip or point value.
5. Calculate the size. Lot size = money at risk ÷ (stop distance × value per pip or point per lot). Round down to the lot step your account allows.

The ATR stop calculator above does the multiple, stop distance and size steps (picking the multiple, finding the stop value and calculating the size). The lot calculator below handles any stop distance, whether it comes from ATR or from chart structure.

Worked example: same risk, different instruments

Suppose you want the same money at risk on EURUSD and on XAUUSD, with the same balance, the same risk percentage and the same ATR multiple.

• Enter the EURUSD ATR into the ATR stop calculator. It returns a fairly narrow stop and a larger lot size.
• Enter the XAUUSD ATR on the same timeframe. Gold usually moves much more, so the calculator returns a wider stop and a smaller lot size.
• Compare the "money at risk" line for both. It should be about the same, apart from small rounding differences caused by lot steps.

You can try a quieter period and a busier period on the same instrument. When ATR rises, the stop widens and the size shrinks. When ATR falls, the stop tightens and the size grows. The calculator shows the exact figures for whatever values you enter, so you do not need to work them out by hand.

Choosing the ATR period and multiple

There is no correct setting. There are only trade-offs:

• Shorter ATR period: reacts quickly to new volatility, but jumps around more.
• Longer ATR period: smoother, but slow to reflect a sudden change.
• Smaller multiple: tighter stop and larger size, but more trades are stopped out by noise.
• Larger multiple: more room for the trade, but a smaller size and a lower reward relative to the stop unless your target is also wider.

Test any combination on a demo account and record the results in a trading journal before you rely on it. Check that your targets still give an acceptable risk-reward ratio. Also compare the ATR stop with the chart levels covered in Stop loss placement.

Limits of ATR stops

• ATR looks back, not forward. It describes recent movement, not the next move.
• Gaps and news. Price can jump past a stop, so the actual loss can be larger than planned. See Gap and weekend risk and Trading news risks.
• Spread and swap. Spread widening can trigger stops earlier than expected. Overnight swap fees add costs that the sizing formula does not include.
• Correlated positions. Equal risk per trade can still add up to a large total if several positions move together. See Correlation risk.
• Leverage. Leveraged CFD and forex trading can lose money fast. A correct lot size limits a planned loss but does not remove that risk. Check the contract specifications and lot steps for each instrument in your broker's official materials.

Frequent questions

Is ATR position sizing better than a fixed lot?

Neither method guarantees results. ATR sizing keeps the money at risk more consistent across instruments and market conditions. A fixed lot keeps the size constant while the risk changes. See Fixed fractional vs fixed lot.

Which timeframe's ATR should I use?

Use the timeframe you base your trade decisions on. ATR from a lower timeframe gives a stop that is too tight for a higher-timeframe trade.

Should I move the stop when ATR changes?

Some traders trail the stop by an ATR multiple as the trade moves in their favour. Moving a stop further away after entry increases your risk beyond the plan.

Does ATR sizing work on indices and crypto CFDs?

The method works the same way on any instrument. Check that you are using the correct point value and contract size for each instrument.

Where can I learn the basics first?

Start with Position sizing and Risk management basics. More tools are on the Calculators page.