The 15-minute opening range (9:30-9:45 ET on U.S. equities) is one of the most commonly discussed ORB variants because it sits between the two extremes: fast but noisy 5-minute ranges, and smooth but slow 30-minute ranges.
Why 15 Minutes
A 5-minute range often gets set before the initial post-open volatility has settled, producing more false breakouts. A 30-minute range waits long enough that a meaningful part of the day's move may already be over by the time a breakout confirms. 15 minutes is a common compromise: long enough to filter out some of the earliest noise, short enough to still catch most of the move.
This is a widely-used convention, not a rule with any special predictive power — plenty of traders use 5-minute or 30-minute ranges successfully. See how to trade an opening range breakout for the general mechanics that apply to any range length.
How to Mark It
At 9:30 ET, start watching price. At 9:45 ET, the range is locked: the highest price traded between 9:30 and 9:45 becomes your upper line, the lowest becomes your lower line. From 9:45 onward, you're watching for a confirmed close beyond either line.
A Worked Example
Say a stock trades between $88.40 and $89.10 from 9:30 to 9:45. At 9:58, a 5-minute candle closes at $89.45 on volume well above the stock's recent average. That's a confirmed break of the 15-minute opening-range high. A trader following this setup would have already decided, before 9:45, that a close back below $89.10 invalidates the trade.
The 15-minute window is a popular convention, not evidence that this specific length outperforms others. Treat the choice of range length as a tradeoff to understand, not a secret setting to optimize.
Practice This Without Risk
Step through real historical opening ranges in Chart Replay before trying this live.
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