Technical analysis · updated October 21, 2026
What is OBV (on-balance volume)
OBV adds the volume traded on days when the price rises and subtracts it on days when the price falls. If OBV is rising, more money is flowing in than out: buyers are more active.
OBV formula
- Volume
- The number of shares traded during the day.
Worked example
On Monday the price rises, with 1 million shares traded. On Tuesday it falls, with 400,000.
On our pages you see the 50-day OBV slope: if it is positive, volume is backing the rise.
How to read OBV
What counts is the direction, not the value: OBV depends on the day you start adding from.
When OBV can fool you
A single day with huge volume (a big trade, joining an index) moves OBV without saying anything about the trend.
Related terms
Questions about OBV
Why does volume matter?
Because a rise on heavy volume shows many convinced buyers, while one on light volume can be fragile.
These explanations are for information only. They are not a recommendation to buy or sell.
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