Volumes is the simplest indicator on this site, and also the one every other volume-based tool here — OBV, Accumulation/Distribution, Money Flow Index, Force Index — is quietly built from. It doesn't accumulate, it doesn't oscillate, and it doesn't compress anything into a bounded scale; it plots one raw number per bar, a histogram of how much trading activity happened during that bar. Where the other volume tools transform that raw number into something derived, Volumes just shows it to you directly, which makes it worth understanding on its own before layering anything else on top of it.
What Volumes Plots
Each bar in the histogram is a single count: how many times the price updated during that bar. Taller bars mean more price updates happened in that period; shorter bars mean fewer. There's no smoothing, no formula, and no comparison against price built in — it's the rawest possible read of market activity, plotted bar for bar underneath the price chart.
That raw simplicity is also Volumes' main advantage over the derived indicators built on top of it. OBV and A/D both transform volume into a cumulative running total that only makes sense compared to its own history; Volumes has no such abstraction layer, so a single bar's reading is immediately interpretable on its own — tall means busy, short means quiet, full stop.
Reading a Volume Spike
The single most useful pattern on a volume histogram is the spike: a bar (or short run of bars) that stands noticeably taller than the bars around it. A volume spike happening at the same time as a significant price move — a breakout past a resistance level, a sharp reversal candle, a fast run in one direction — is generally read as a sign that the move has real participation behind it, not just a handful of thin prints drifting price around. The diagram above shows the pattern: an ordinary, unremarkable volume histogram suddenly spikes on the exact bar price breaks out, which is a stronger breakout than the identical price action occurring on quiet, average volume would be.
The reverse is just as informative. A price move on conspicuously low volume — especially a breakout — is a reason for caution rather than confidence, since it suggests few participants are actually behind the move, leaving it more vulnerable to reversing once a bit of counter-pressure shows up. Low volume during a session's typically slow hours (see Trading Sessions) is expected and not itself a warning sign; the pattern worth watching for is low volume at a moment when the price action implies something significant should be happening.
Volumes vs the Derived Volume Indicators
It's worth being explicit about how Volumes relates to the other volume tools on this site, since they're easy to lump together. Volumes is the raw input; OBV, A/D, MFI, and Force Index are all different transformations applied to that same raw input, each answering a different question:
- Volumes — how much activity happened on this bar, full stop.
- OBV — a cumulative running total, adding a bar's full volume on an up-close and subtracting it on a down-close, used to spot divergence between price and accumulated buying/selling pressure over time.
- A/D — the same cumulative idea as OBV, but weighting each bar's volume by exactly where the close landed within that bar's own high-low range, rather than a simple up/down count.
- MFI — volume-weighted price movement compressed into a bounded 0-100 oscillator, read the way you'd read RSI.
- Force Index — volume multiplied by the size of the price change from the previous close, capturing the combined force of a move rather than just its participation level.
None of these replace Volumes — they all still ultimately depend on the same raw tick-volume input this indicator plots directly. Volumes is most useful as the first, simplest check ("was this move backed by activity or not?"), while the derived indicators are better suited to spotting patterns — divergence, momentum shifts — that require comparing volume's behavior against itself or against price over many bars.
Entry Conditions: The Volume Spike Alert
Because a raw volume count has no natural threshold to alert on, the included indicator manufactures one the same way the other tools on this site do: it computes a simple moving average of volume over a configurable AveragePeriod (20 bars by default), then fires when the current bar's volume exceeds that average by a configurable multiple.
- Spike alert — the just-closed bar's volume is greater than
SpikeMultiplier × the AveragePeriod-bar average volume(default multiplier 2.0, meaning volume needs to be at least double its recent average to qualify).
Unlike the other alert indicators on this site, this signal has no BUY/SELL direction of its own — a volume spike says something happened, not which way it went. Pair the alert with the direction of the candle it fires on (or with price structure more broadly) to decide what the spike actually means for that bar.
Parameters
- AppliedVolume (MT5 only, default
VOLUME_TICK) — which volume series the histogram plots. MQL4'siVolume()always returns tick volume directly, with no equivalent input. - AveragePeriod (default 20) — the lookback window for the moving average that current volume is compared against. Shorter periods make the average more reactive, so it takes a bigger relative spike to still trigger; longer periods smooth the average out, making moderate spikes easier to trigger against a steadier baseline.
- SpikeMultiplier (default 2.0) — how many times the average volume the current bar must exceed to count as a spike. Raising it (e.g. 3.0) restricts alerts to only the most extreme volume bursts; lowering it (e.g. 1.5) fires more often, including on more moderate upticks in activity.
- EnableAlert (default true) — pop up a terminal alert the moment a volume spike is detected.
- EnablePush (default false) — also send a push notification to your phone via MetaTrader's mobile app.
The Forex Tick-Volume Caveat
This caveat matters more here than anywhere else on the site, because Volumes is the raw number every other volume tool depends on — any imprecision in it propagates into all of them. Forex is an over-the-counter market with no central exchange, so there's no single, universally agreed record of how many units of a currency pair actually changed hands during a given bar. What MetaTrader plots by default is tick volume — a count of how many times the quoted price updated — not true traded volume, which generally isn't reported for currency pairs at all (the MQL5 build's VOLUME_TICK default makes this explicit, since the alternative VOLUME_REAL setting typically has no data behind it on forex symbols).
Tick volume correlates reasonably well with genuine trading activity in practice — busier markets really do generate more quote updates — but each broker only observes its own slice of the global market's liquidity providers and price feed, so the exact bar-by-bar volume histogram can differ somewhat between brokers even for the identical pair and timeframe. This doesn't make the indicator useless; spikes and quiet stretches still show up in roughly the expected places. It just means a "2x average" spike on your broker's feed is a read on quoting intensity through your specific liquidity connection, not a literal count of contracts traded across the whole global forex market.
A Word of Caution
Volume on its own says nothing about direction, and a spike can just as easily accompany a sharp reversal against the prevailing trend as it can confirm a continuation — always read a spike alongside the price action that produced it, not as a standalone signal. Because tick volume is a proxy rather than a precise measurement, treat a single borderline spike (say, 2.1x average when the threshold is 2.0x) with less confidence than an obvious, order-of-magnitude spike. As with every tool on this site, combine a volume read with price structure (see Support and Resistance and Trend vs Range) rather than acting on volume in isolation, and always size positions with a defined stop before acting on any signal — see Risk Management Basics for the position-sizing math.
Download the Indicator
This custom indicator plots tick volume as a histogram in a separate window and automatically alerts when the current bar's volume spikes above a multiple of its own recent average. A version for each platform — MetaTrader 4 and MetaTrader 5 — is linked below.