ATR: dynamic stops and volatility-based risk.

Most traders set their stop at a fixed number: "a 100-point stop". The problem? 100 points can be painfully tight on a volatile day (and you get stopped out by noise) or far too loose on a quiet day (and you risk more than you need to). The ATR solves this by letting the stop breathe with volatility. It is the indicator that turns amateur risk management into professional risk management.

01What the ATR is

ATR stands for Average True Range , created by Wilder (the same man behind the RSI). It measures how much price usually moves over a given period — in other words, volatility. Important: the ATR has no direction. It does not tell you whether price will go up or down, only the typical size of the move. An ATR of 150 on Brazil's WIN mini index future means that, on average, price swings ~150 points per candle over that period.

02The main use: a dynamic stop loss

The classic application is the ATR-multiple stop. Instead of "a 100-point stop", you use "a stop 2× the ATR away". So:

• Volatile market → high ATR → wide stop → you do not get stopped out by normal noise.
• Calm market → low ATR → tight stop → you risk less when you do not need that much room.

The common multiple is between 1.5× and 3× the ATR, depending on how much room the strategy needs. The bigger the multiple, the more room the trade has to breathe (and the bigger the potential loss per trade).

03ATR-based position sizing

The ATR also answers "how many contracts should I trade". Combining the ATR stop with your risk per trade, the sizing happens automatically:

Notice the lesson built in: when volatility is high (big ATR), the stop is wide, and to respect your 2% risk you have to trade fewer contracts. The ATR forces you to cut exposure exactly when the market is dangerous. It is automatic risk management.

04Coding the ATR and the stop

//@version=5
strategy("Stop por ATR", overlay=true)

periodo = input.int(14, "Período ATR")
mult    = input.float(2.0, "Múltiplo do ATR")

atr = ta.atr(periodo)

// example: enter at the moving average and use ATR for the stop
ma = ta.ema(close, 21)
if ta.crossover(close, ma)
    stopLoss = close - mult * atr
    takeProfit = close + mult * atr * 2   // target 2x the risk
    strategy.entry("Compra", strategy.long)
    strategy.exit("Saida", "Compra", stop=stopLoss, limit=takeProfit)

plot(atr, "ATR", color=color.purple, display=display.data_window)

import pandas as pd

def calcular_atr(df, periodo=14):
    alta_baixa = df["high"] - df["low"]
    alta_fech  = (df["high"] - df["close"].shift()).abs()
    baixa_fech = (df["low"]  - df["close"].shift()).abs()
    # True Range = the largest of the three
    tr = pd.concat([alta_baixa, alta_fech, baixa_fech], axis=1).max(axis=1)
    return tr.ewm(alpha=1/periodo, adjust=False).mean()

df["atr"] = calcular_atr(df)

# dynamic stop and position sizing
entrada = df["close"].iloc[-1]
atr_atual = df["atr"].iloc[-1]
stop = entrada - 2 * atr_atual

risco_reais = 100          # 2% of a 5000 account balance
valor_ponto = 0.20          # WIN
perda_por_contrato = (entrada - stop) * valor_ponto
contratos = int(risco_reais / perda_por_contrato)
print(f"Stop: {stop:.0f} | Contratos: {contratos}")

05Other uses of the ATR

• Trailing stop: moving the stop as price advances, always keeping it 2× ATR away — it locks in profit without choking the trade.
• Volatility filter: only trading when the ATR is above a minimum (avoids a dead market) or below a maximum (avoids extreme volatility).
• Proportional target: setting take profit as a multiple of the ATR, keeping the risk/reward ratio consistent in any regime.

06Frequently asked questions