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Volume Oscillator on TradingView: formula and limits

The Volume Oscillator compares a fast average of volume with a slow average. A positive value means the fast average is higher. It measures a change in trading activity; price direction is absent from the calculation.

Difference = Fast volume MA − Slow volume MA

Percent = 100 × Difference / Slow volume MA

This guide covers the two-average definition. TFS Volume Oscillator signs volume by candle direction and is a separate algorithm. The earlier TFS example on this URL has been replaced.

Read and copy the codeCheck the calculation
Hypothetical volume pulse: a 2-bar SMA oscillator stays positive on bar 5 and turns negative on bar 6 while current volume stays at 100.
Illustrative data, not a market chart or backtest. The table below provides the inputs and calculations.

Choose the scale before comparing values

A raw difference keeps the units supplied by the chart feed. A percentage divides by the slow average, so a value of 20 means that the fast average is 20% above the slow average. It is neither a 20% price return nor a share of buying volume.

Output definitions and their limits
OutputFast 200, slow 150Constraint
Difference50 volume unitsMagnitude depends on feed units and activity.
Percent33.33%Requires a positive slow average.
Percent with fast denominator25%Different formula; do not compare as identical.

TradingView documents the slow-average denominator for PVO. Its full PVO also adds a signal line and a histogram equal to PVO minus that signal. The bars in our code show the oscillator itself, without that extra subtraction. See the PVO guide for the separate three-series structure.

A volume spike can change the sign after it has passed

Use these six hypothetical bars in order: 100, 100, 100, 300, 100, 100. Set fast length to 2 and slow length to 4. For SMA, average the latest 2 or 4 observations. For EMA, seed both averages at the first observation, 100, and use α = 2 / (length + 1).

Synthetic volume units; values rounded only for display.
BarVolumeFast SMASlow SMASMA diff.SMA %EMA %
4300200.00150.0050.0033.33%29.63%
5100200.00150.0050.0033.33%−2.40%
6100100.00150.00−50.00−33.33%−10.86%

At bar 4, the SMA values are (100 + 300) / 2 = 200 and (100 + 100 + 100 + 300) / 4 = 150. At bar 6, the spike has left the fast window but remains in the slow window. The resulting −33.33% occurs even though bars 5 and 6 have identical volume. No price movement or selling pressure was needed to create that negative reading.

EMA follows a different path: at bar 4, fast = 233.3333 and slow = 180; at bar 5, fast = 144.4444 and slow = 148. Its percentage has already turned negative. SMA removes an observation at a fixed window boundary; EMA decays its influence recursively. Different lengths, seeds or smoothing methods can therefore change the crossing bar.

Complete Pine Script v6: inspect both averages

Paste this standalone educational indicator into Pine Editor and add it to your chart. It supports EMA or SMA, raw or percent output, a status message and confirmed zero-crossing alerts. The Data Window exposes both averages and both output scales. This is a custom example, not a claim that the Pineify visual editor has a matching module.

Pine v6 · chart timeframe
//@version=6
indicator("Volume Oscillator: auditable averages", overlay=false, precision=2)

fastLength = input.int(5, "Fast length", minval=1, maxval=500)
slowLength = input.int(10, "Slow length", minval=2, maxval=500)
maType = input.string("EMA", "Average type", options=["EMA", "SMA"])
outputMode = input.string("Percent", "Output", options=["Percent", "Difference"])
confirmedOnly = input.bool(true, "Show only closed bars")

if fastLength >= slowLength
    runtime.error("Fast length must be less than slow length.")

// Explicit EMA seed: first valid volume. A missing bar resets the state.
resetEma(float source, int length) =>
    float alpha = 2.0 / (length + 1)
    var float average = na
    average := na(source) ? na : na(average[1]) ? source : alpha * source + (1 - alpha) * average[1]
    average

validVolume = not na(volume) and volume >= 0
sourceVolume = validVolume ? volume : na
var int validRun = 0
validRun := validVolume ? validRun + 1 : 0
fastEma = resetEma(sourceVolume, fastLength)
slowEma = resetEma(sourceVolume, slowLength)
fastSma = ta.sma(sourceVolume, fastLength)
slowSma = ta.sma(sourceVolume, slowLength)
fastAverage = maType == "EMA" ? fastEma : fastSma
slowAverage = maType == "EMA" ? slowEma : slowSma
ready = validRun >= slowLength
rawDifference = ready ? fastAverage - slowAverage : na
percentDifference = ready and slowAverage > 0 ? 100 * rawDifference / slowAverage : na
oscillator = outputMode == "Percent" ? percentDifference : rawDifference
showBar = not confirmedOnly or barstate.isconfirmed

plot(showBar ? oscillator : na, "VO (selected units)", color=oscillator >= 0 ? color.blue : color.orange, style=plot.style_histogram, linewidth=2)
hline(0, "Zero", color=color.gray)
plot(showBar and ready ? fastAverage : na, "Fast volume average", display=display.data_window)
plot(showBar and ready ? slowAverage : na, "Slow volume average", display=display.data_window)
plot(showBar ? rawDifference : na, "Difference (volume units)", display=display.data_window)
plot(showBar ? percentDifference : na, "Difference (%)", display=display.data_window)

crossUp = ta.crossover(oscillator, 0)
crossDown = ta.crossunder(oscillator, 0)
alertcondition(barstate.isconfirmed and crossUp, "VO above zero", "Fast volume average crossed above slow volume average at close.")
alertcondition(barstate.isconfirmed and crossDown, "VO below zero", "Fast volume average crossed below slow volume average at close.")

var table status = table.new(position.top_right, 1, 1)
if barstate.islast
    string message = not validVolume ? "Volume missing or invalid" : not ready ? "Waiting for consecutive volume bars" : outputMode == "Percent" and slowAverage == 0 ? "Percent undefined: slow average is zero" : not showBar ? "Waiting for bar close" : outputMode == "Percent" ? "VO unit: percent" : "VO unit: supplied volume"
    table.cell(status, 0, 0, message, text_color=color.white, bgcolor=color.new(color.black, 20))

Implementation policy: require slow-length consecutive valid bars before output. Missing or negative volume resets the EMA seed and the valid-bar count; zero volume is valid. EMA starts from the first valid volume after a reset. This deliberate policy may differ from the gap handling of another script or initialization.

Inputs and failure states to check

Setting or conditionBehavior in this example
Fast 5, slow 10; EMADemonstration defaults, measured in chart bars. Fast must be smaller than slow; otherwise the script reports an error.
Show only closed bars: onThe current open bar remains blank until its closing update. Alerts always require bar close, even with live plotting enabled.
No volume or an isolated missing barOutput is unavailable. Require a new consecutive valid run; do not replace missing data with zero.
Four zero bars with SMA 2/4Both averages are zero. Difference is 0; percent is undefined and stays blank, rather than displaying a fabricated 0%.
Tiny positive slow averageThe percentage can be large. Inspect the underlying averages before applying a threshold.
Tick volume or different providersReadings describe the supplied series. Price-update counts and traded shares are different inputs; percent normalization does not make the feeds equivalent.

How to use the Volume Oscillator indicator on TradingView

  1. Choose the exact exchange or data provider, symbol, chart timeframe and session. Confirm that Volume has usable data. A missing feed cannot be repaired by an oscillator.
  2. Set the same lengths and average type in both scripts being compared. Match the denominator and determine whether a histogram shows the main oscillator or main minus signal.
  3. Select a closed bar and inspect fast average, slow average, raw difference and percent in the Data Window. Recalculate one bar before comparing crossings.
  4. Inspect an isolated volume spike, a quiet interval and a session transition. A crossing can come from old volume leaving a window; keep price evidence separate.
  5. If you later build a strategy, specify entries, exits, sizing and transaction costs separately. Validate calculations first, then evaluate the trading rules.

The code runs on the chart timeframe and does not request another timeframe. Bar-close confirmation removes the unfinished-bar value from this display; it does not guarantee identical results after a data-provider revision. Educational material, not investment advice.

Volume Oscillator questions

The fast volume average exceeds the slow volume average. The formula uses unsigned volume, so a positive value does not identify buying pressure or predict rising prices.

This page uses the slow volume average: 100 × (fast average − slow average) / slow average. With fast 200 and slow 150, the result is 33.33%. Dividing by fast instead gives 25%, which is a different definition.

No. TFS signs the volume of each bar by close versus open before averaging. This page compares two moving averages of unsigned volume. The previous example on this URL used TFS; the replacement code implements the two-average definition.

Check the status message. This example waits for consecutive valid volume bars equal to the slow length, leaves an open bar blank by default, and suppresses percentage output when the slow average is zero. A symbol without volume cannot produce a meaningful result.

There is no universal best pair. The example starts with 5 and 10 bars using EMA. Keep the fast length below the slow length and compare one change at a time on the same symbol, session and timeframe. These are demonstration inputs, not optimized trading parameters.

A zero crossing describes the relationship between two volume averages. A strategy still needs price direction, entry and exit rules, sizing, costs and an evaluation period. The supplied indicator places no orders and makes no return claim.

Sources and related calculations

Official references checked October 17, 2026. Tables and the pulse diagram are original hypothetical calculations.

For a different input construction, see OBV Oscillator. Return to TradingView indicator guides for the category overview.

Specify the calculation before asking for code

Use Pine Script AI Coding Agent to describe or adapt your version. Include the two lengths, SMA or EMA, output units, the slow-average denominator, missing-data policy and confirmation time. Ask for both averages in the Data Window so you can compare each bar.

Example request: "Adapt the supplied Volume Oscillator to SMA 2/4, show percent, leave undefined values blank, and alert only on confirmed crossings. Keep the diagnostic averages." Review the generated source and chart values before relying on alerts.

Open Pine Script AI Coding Agent