What Is Volume in Stock Trading? How to Use It With RSI, VWAP and EMA
Volume tells you how many shares, contracts, or lots traded in a stock during a set period. It has nothing to do with price. It only counts activity.
Every trade needs a buyer and a seller, and volume counts that trade once, no matter the price. But if the same shares change hands more than once in a day, each of those trades adds to the count separately.
Say a trader buys 100 shares in the morning. By afternoon, another trader buys those same 100 shares off them. That is two separate trades, so the day's volume reads 200, even though only 100 shares actually exist and changed hands twice.
Think of it as a crowd meter for a stock. A busy market means more traders are active. A quiet one means barely anyone showed up.
What High Volume Means
High volume points to strong interest in a stock. More traders are buying and selling, so orders move faster.
→ Trades fill quickly, with less slippage → Price moves reflect real demand, not one large order → Breakouts backed by volume tend to hold longer
A stock that jumps 5% on three times its average volume has real buying behind it. The same jump on thin volume often fades within a day or two.
Related Reads: → What Is the Impact of Slippage on an Algo?
What Low Volume Means
Low volume means fewer traders are active. It usually signals weak interest or low liquidity.
→ Wider bid-ask spreads → Harder to enter or exit large positions without moving the price → Sharp swings on a single big order
Low-volume stocks look exciting because they move fast. But that speed works against you too. Getting in is easy. Getting out at your price is not.
Say a small-cap stock that usually trades 50,000 shares a day suddenly sees only 5,000. A single order for 2,000 shares can now swing the price sharply, not because demand changed, but because there is nobody left to absorb it. The same order in a high-volume stock barely moves the price at all.
Related: What Is Square Off in Trading?
How to Use Volume in Trading
Volume alone will not tell you where a stock is headed next. What it tells you is how much to trust the move you are already seeing.
Confirm the trend
Price and volume should move together. Rising price with rising volume signals genuine buying. Rising price with falling volume signals a weak rally that could reverse soon.
Catch breakouts early
Watch for a volume spike, two or three times the 20-day average, near a support or resistance level. That spike usually means bigger players are stepping in, not just retail noise.
Pair it with indicators
Volume works best alongside RSI, moving averages, or Supertrend. An RSI crossover on high volume carries more weight than the same crossover on a quiet day. But do not trade a combination like this on gut feel. Test it on historical data first.
Related Reads: → Volume + VWAP + EMA Combined Strategy
Watch key levels
Volume often spikes near round numbers, previous highs, or opening range breakouts. A level that breaks on low volume is weak. A level that breaks on high volume usually holds.
Where to Track Volume
Every trading platform shows volume as bars below the price chart. NSE and BSE list it on their own sites too. Green bars usually mean buying pressure, and red bars usually mean selling pressure.
The problem is scale. Reading volume bars across dozens of stocks by eye does not work for most traders. If you want to trade a rule like "buy when volume crosses two times average and RSI is above 60," you need to test that rule across years of data first, not just watch one chart.
Related Reads: → Essential Stock Option Trading Terms
Conclusion
Volume is one of the simplest concepts in trading, and one of the easiest to misuse. The real edge is not in spotting a volume spike. It is in knowing, with data, whether that kind of spike has actually worked before.
That is where AlgoTest's Signals come in. You can set volume-based conditions, like volume crossing above a moving average, alongside indicators such as RSI or Supertrend, and backtest the whole strategy on years of Nifty and Bank Nifty data. No coding, no manual chart-watching, just a clear answer on whether your idea would have worked.
If you are tired of guessing what a volume spike means, build the rule and let the backtest answer it.
Join AlgoTest as we simplify algo trading in India, end-to-end.
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