On this page
Delta Acceleration — Tape & flow, in its own panel below the chart.
What Delta Acceleration measures
Delta is buying minus selling within a bar; this indicator takes the difference between consecutive values, with a lag fixed at one bar, and draws it as a signed histogram. Two bars at plus 200 each produce zero acceleration, because the pressure was steady; plus 50 followed by plus 200 produces a strongly positive value, because the buying intensified. No session anchoring applies: the output is a difference between two bar aggregates rather than a running total, so there is nothing to anchor, unlike cumulative delta. The first bar of a series has no value, because there is no previous bar to compare it with.
The formula, as implemented
This is not how the indicator is usually defined elsewhere — it is what the shipped code computes, documented next to the implementation:
Accélération du delta — dérivée seconde du flux : value = delta(t) − delta(t−1) POURQUOI : le delta dit la pression, son accélération dit si elle S'INTENSIFIE ou s'essouffle. Deux barres à +200 de suite = pression stable (accélération nulle) ; +50 puis +200 = les acheteurs montent le ton. C'est le signal qui précède les cassures, et il est invisible sur l'histogramme de delta seul. Convention : lag FIXE d'une barre et sortie HISTOGRAMME SIGNÉE — à ne pas confondre avec `delta-momentum` (delta.ts), qui est un ROC paramétrable en ligne (défaut N=5). Pas de reset de séance : c'est une DIFFÉRENCE de deux agrégats de barre, pas un cumul — rien à ancrer (le CVD, lui, est ancré). Première barre → PAS de point : on ne compare jamais à une barre inventée.
How to read it
- The sign shows the direction in which pressure changed, not the direction of the flow itself. A negative bar can follow strong buying that simply eased.
- Zero means stable pressure, which is an observation in its own right: flow continued at the rate of the previous bar.
- Repeated same-sign bars describe pressure building over several bars, the pattern this indicator exists to expose and the one a plain delta histogram flattens.
- A sharp reversal in acceleration while delta stays positive says the push is losing intensity before it loses direction.
- Since the value is a difference of two bars, a single extreme print often reflects an unusually quiet previous bar; check both bars before reading anything into it.
Parameters and defaults
The one-bar lag belongs to the definition and is not adjustable; for a configurable lookback, the delta momentum measure covers that case with a rate of change over 5 bars by default. Positive and negative bars take their own colours. Smoothing is 1 out of the box, leaving the histogram raw — averaging a difference series reduces its spikiness and also its point, since the spikes are the acceleration events.
| Parameter | Type | Default | Range |
|---|---|---|---|
| Smoothing | number | 1 | 1 – 200 |
What it does not show
A difference of two bars is noisy by construction, and the series changes sign frequently in ordinary two-sided trade. It inherits everything delta depends on, including aggressor-side classification, and it has no notion of price, so intensifying flow into a level looks identical to intensifying flow into open space. Bar boundaries dominate the result: the same trades split differently across two bars produce a different acceleration. The first bar of the chart has no value.
Related indicators
- Tape Speed — Tape & flow
- Diagonal Imbalances — Tape & flow
- Stacked Imbalances — Tape & flow
- Absorption Score — Tape & flow
- Unfinished Auctions — Tape & flow
- Effort vs Result — Tape & flow
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Frequently asked questions
- What is delta acceleration in orderflow?
- It is the change in delta between two consecutive bars — this bar's buying minus selling, less the previous bar's. Delta tells you which side was pressing; acceleration tells you whether that pressure grew or eased. A steady stream of identical deltas produces an acceleration of zero.
- How does delta acceleration differ from delta momentum?
- Delta acceleration uses a fixed one-bar lag and is drawn as a signed histogram. Delta momentum is a rate of change over a configurable window, five bars by default, drawn as a line. One reacts to the immediately preceding bar, the other to a longer stretch of them.
- Why is there no delta acceleration value on the first bar?
- Because the calculation needs a previous bar to subtract from. Rather than compare against an assumed starting value, which would invent a first reading, the first bar is left without a point.