Cumulative Volume Delta accumulates the signed difference between ask-side and bid-side volume across a chosen period and plots the running total as a line. It summarizes net aggressive flow instead of price itself, so the line can rise while price stands still or fall while price drifts up. This page covers anchor points, the aggregation interval, divergence settings, axis handling, smoothing and the choice between a sub-panel and an overlay.
01 Anchor points
The anchor is the moment at which the accumulator resets to zero. Everything after the anchor is summed into the running total.
- Session anchor — reset at each scheduled session boundary.
- Day anchor — reset at midnight in the chart time zone.
- Week anchor — reset at the first session of the week.
- Custom anchor — reset at a timestamp entered by the operator, or at the first bar of the visible range.
With a session anchor on a five-minute chart, the first bar of a new session always starts at zero and the line can therefore be compared across days. With a custom anchor placed before a scheduled event, the total before and after the event can be read directly from the same line.
02 Delta aggregation
Delta for a single bar is the ask volume of that bar minus its bid volume. The aggregation interval decides how many bars are merged before that difference is added to the running total.
| Setting | Effect |
|---|---|
| Per bar | one step per bar, most reactive |
| Ticks per step | merge n ticks before adding |
| Volume per step | merge until n size has traded |
| Minimum trade size | ignore prints below a floor |
| Include extended hours | on or off |
Raising the minimum trade size reduces noise from small prints but also removes genuine small aggression. The floor should be chosen from the visible trade-size distribution of the instrument.
03 Divergence detection
Divergence detection compares price extremes with extremes of the cumulative line inside a look-back window. When price prints a higher high but the cumulative line prints a lower high, the condition is flagged, and the mirrored test applies to lows. Settings are the look-back length in bars, the minimum price distance in ticks between the two extremes, and the minimum difference of the cumulative values. Flags can be painted on the bars that formed the extremes or listed in a table with the two extreme prices and the gap between them.
04 Axis normalisation
The cumulative scale is not a price scale, so it must be mapped onto the panel in one of three ways.
- Own scale — the line uses a dedicated axis fitted to its own minimum and maximum in the visible range.
- Percentage of range — the line is normalised against the price range of the window, so it can be read against price levels.
- Zero baseline — the axis is anchored at zero at the anchor point, which keeps the sign of the total meaningful across the whole window.
On an overlay the own scale is usually replaced by a percentage of range, because the price axis must keep its own meaning. On a sub-panel the own scale is the natural choice, since nothing else shares the axis.
05 Smoothing
Smoothing reduces small steps in the line without changing the anchor. Two filters are available: a simple average over n steps and an exponential average with a decay factor. A simple average of 5 steps flattens short reversals and delays each turn by roughly two steps; an exponential average with the same period reacts sooner at the cost of leaving more residual noise. Smoothing is applied for display only and does not alter the stored totals, so switching it off restores the raw line immediately. When divergence detection is active, the detection window can be configured to run against the smoothed line or the raw line.
06 Sub-panel or overlay
Both placements use the same accumulator and differ only in how the line is drawn.
- Sub-panel
- Separate panel below the price chart with its own axis, full height for the line and no overlap with bars.
- Overlay
- Line drawn inside the price panel, offset from the price scale, with a semi-transparent fill against the panel background.
- Hybrid
- Overlay for short windows and a sub-panel for long windows, switched manually per workspace.
