Accelerator Oscillator Indicator: Formula, Settings and How to Read It
The Accelerator Oscillator is a Bill Williams momentum histogram that subtracts a simple moving average of the Awesome Oscillator from the Awesome Oscillator itself. Where the AO measures the speed of a move, the AC measures whether that speed is rising or falling.
Senzoukria · Indicators · Updated September 2026
Accelerator Oscillator ships with the Senzoukria desktop app, in the Momentum group of the indicator catalogue. It is drawn in its own panel below the chart.
What Accelerator Oscillator measures
The calculation starts from the median price of each bar, (high + low) / 2. The Awesome Oscillator is the 5-period simple moving average of that median minus the 34-period one, and the Accelerator subtracts a further 5-period simple average of the AO from the AO. A positive value therefore means momentum is currently running above its own recent average; a negative one means it is falling back toward it. The smoothing average refuses any window containing a missing value instead of averaging over whichever bars happen to exist, so the first plotted point lands at index slow + smooth − 2 — index 37 with the defaults, which is the 38th bar of the series.
The formula, as implemented
This is not a description of how the indicator is usually defined elsewhere — it is what the shipped code computes, documented next to the implementation:
Accelerator Oscillator (Bill Williams) — la DÉRIVÉE de l'Awesome : AC = AO − SMA_smooth(AO) (SMA simple, comme l'AO lui-même) POURQUOI : l'AO mesure la vitesse du momentum, l'AC son accélération — l'idée de Williams est que l'accélération tourne AVANT la vitesse. Défauts 5/34/5 (Williams). WARM-UP composé : l'AO n'existe qu'à partir de `slow` barres, sa SMA en exige `smooth` de plus → premier point à l'indice slow + smooth − 2. La SMA traverse une série À TROUS (`smaNullable`) : elle refuse toute fenêtre incomplète plutôt que de moyenner sur ce qui existe. Histogramme : pas de point tant que ce n'est pas défini. Même convention de couleur par SIGNE que l'AO (cf. sa déf).
How to read it
- Read the sign against the zero line: bars above zero say momentum is building, bars below say it is draining, whatever direction price is going.
- A run of shrinking bars on the same side of zero is the case the indicator was built for — acceleration fading while the oscillator underneath has not crossed yet.
- Compare AC with AO on the same chart: AC turning while AO still extends is the ordering Williams described, and it is a warning, not a trigger.
- A large bar means the AO has pulled far away from its own average, which describes a recent burst of speed rather than what comes next.
- Values that hug zero for long stretches describe a market with no momentum trend, where the sign flips on noise.
Parameters and defaults
fast and slow (5 and 34 by default) define the Awesome Oscillator underneath, while smooth (5) sets the average the AO is measured against. Lengthening smooth makes the histogram slower and its sign changes rarer; shortening it makes the AC track AO's bar-to-bar changes and flip often. Every increase also pushes the first usable bar further right, because the warm-up periods add up.
| Parameter | Type | Default | Range |
|---|---|---|---|
| Fast SMA | number | 5 | 1 – 200 |
| Slow SMA | number | 34 | 2 – 500 |
| AO smoothing | number | 5 | 1 – 200 |
What it does not show
The Accelerator is built from bar highs and lows only — no traded volume, aggressor side or order book reaches it, so it cannot tell a rise driven by aggressive buying from one drifting up on a thin book. Being a difference of averages of a difference of averages, it lags twice over, and its sign changes after the price turn, not before it. On instruments or sessions with few trades the median price is a poor summary of the bar, and the histogram then reacts to jumps in that midpoint rather than to real acceleration. Note also that smooth happens to default to 5, the same number as fast, but the two are independent: fast changes the AO underneath, smooth only changes what the AO is compared against.
Using it in Senzoukria
Add it from the Indicators panel of any footprint chart or candle chart. It runs on futures data from Rithmic or Databento and on crypto pairs from Binance and Bybit, on the same engine — the calculation does not change with the venue, only the data feeding it does. Market data subscriptions are billed by the provider, separately from the app.
Related indicators
See the full indicator library, or start with the order flow guide if you are new to reading aggression, delta and absorption.
Frequently asked questions
- How is the Accelerator Oscillator different from the Awesome Oscillator?
- The Awesome Oscillator is the gap between a 5-period and a 34-period simple average of the median price, so it measures the speed of a move. The Accelerator subtracts a 5-period average of the AO from the AO, which measures whether that speed is increasing or decreasing. Because the AC crosses zero when the AO crosses its own average, and the AO crosses zero only when its two price averages cross, the AC changes sign more often and cannot exist before the AO does.
- Why does the Accelerator Oscillator only start after several dozen bars?
- Its warm-up is cumulative. The Awesome Oscillator has no value until the slow average is complete — 34 bars by default — and the AC's own smoothing average then needs 5 consecutive AO values on top of that. The first point therefore lands at index slow + smooth − 2, index 37 with default settings, and it moves further right if you lengthen any period.
- What do the colors of the Accelerator histogram mean?
- In Senzoukria the histogram is colored by sign: bars above zero use the positive color, bars below the negative one. Bill Williams' original version colors each bar according to whether it is higher or lower than the previous bar, which is a different rule and can point the other way on the same data. Check which convention a platform uses before carrying a color habit across.