Acceleration Bands on TradingView: Formula and Breakout Conditions
Acceleration Bands expand each bar's high and low by a normalized range, then smooth those expanded prices with a simple moving average. A close outside a band describes a breakout condition; a second consecutive close adds confirmation without guaranteeing continuation.
Use the public factor-4 calculation below to compare values, distinguish a wick from a completed close, and define exactly when an alert should fire. Different scripts can use different formulas or filters, so matching the indicator name is insufficient.
Check the formula and worked exampleExpand each bar, then smooth
The TC2000 public formula uses a width parameter. At width 1, define H as high, L as low, C as close, and n as the number of bars:
r = (H - L) / (H + L)
Upper = SMA(H × (1 + 4r), n)
Middle = SMA(C, n)
Lower = SMA(L × (1 - 4r), n)
The denominator is H + L, not their average. Using (H + L) / 2 requires changing the multiplier from 4 to 2 to preserve the same result. Compute the transformed price on every bar before averaging. Applying the expansion to already averaged highs and lows generally gives different values.
A reproducible 20-bar example
Assume 20 consecutive bars each have H = 102, L = 98 and C = 100. The ratio is 4 / 200 = 0.02. Every transformed high is 102 × 1.08 = 110.16; every transformed low is 98 × 0.92 = 90.16. Their 20-bar averages are therefore 110.16 and 90.16, while the middle is 100.
The distances from the middle are 10.16 and 9.84. Although descriptions sometimes call Acceleration Bands equidistant, this public high/low calculation is not generally symmetric around the SMA of closes. Its band midpoint here is 100.16. Do not replace the lower line with a reflection of the upper line.
Denominator and initialization boundaries
- H + L = 0 makes the ratio undefined. A denominator close to zero can magnify small changes. Reject invalid bars explicitly in a custom version; silently substituting zero range changes the method.
- The intended domain here is positive prices with H ≥ L. For negative-price instruments or synthetic spreads, the ratio can change sign or become unstable. This interpretation does not carry over automatically.
- Even with positive prices, the lower multiplier becomes negative when 3H > 5L. A negative lower band is a mathematical output, not a tradable support price.
- With complete data, a 20-bar SMA first has a full window on bar 20. If a custom version rejects a bar, define whether it requires 20 consecutive valid bars before signals resume; skipping missing values is a different policy.
One close, two closes, and a failed breakout
Price Headley's explanation describes two consecutive closes above the upper band and a traditional exit on one close back inside. It also warns that choppy markets can produce false signals. A two-close condition filters out some one-bar excursions but enters later and can still fail.
Use strict comparisons: a long-side outside close means C is greater than that bar's upper band. Equality is a touch. For two-bar confirmation, compare the previous close with the previous upper band and the current close with the current upper band. Do not compare both closes with today's band.
| Case | Bar A | Bar B | Result after B closes |
|---|---|---|---|
| Wick only | High 103; close 101.8; upper 102 | Close 101.7; upper 102.1 | No outside close; no two-close confirmation |
| One-bar excursion | Close 102.4; upper 102 | Close 101.8; upper 102.2 | One-close rule fires at A; two-close rule never confirms |
| Two closes, then failure | Close 102.4; upper 102 | Close 102.6; upper 102.2 | Confirms at B; a later close 101.9 below upper 102.3 ends the run |
| Exact touch | Close 102; upper 102 | Close 102.4; upper 102.2 | Only B qualifies; equality on A is not outside |
For a mirrored short-side experiment, require each close below its own lower band and define the return-above rule separately. If an alert should fire once per breakout, trigger only when the consecutive-close count first reaches two. A condition that stays true on bars three and four can otherwise repeat the alert.
The open bar changes its high, low, close and band values. Evaluate close-based conditions after the bar completes and align the alert frequency with that choice. TradingView explains this realtime behavior. The next executable order price may differ from the signal close because of gaps, spread and slippage.
Compare AB, Bollinger and Keltner on the same window
Use the same 20 hypothetical bars above, with the previous close also 100. For the Keltner comparison, assume EMA and ATR have already stabilized on identical earlier bars. Set both lengths to 20 and the ATR multiplier to 2. This isolates how the width measures differ.
| Indicator and settings | Width input | Middle | Upper / lower |
|---|---|---|---|
| Acceleration Bands, n = 20, factor 4 | (102 - 98) / (102 + 98) = 0.02 | 100 | 110.16 / 90.16 |
| Bollinger, SMA(20), 2 standard deviations | All closes are 100, so standard deviation = 0 | 100 | 100 / 100 |
| Keltner, EMA(20), 2 × ATR(20) | True range = 4; stabilized ATR = 4 | 100 | 108 / 92 |
Bollinger Bands measure dispersion of the selected source; with close as the source, intrabar movement alone need not produce dispersion. An ATR-based Keltner Channel measures ranges around a moving average. Acceleration Bands average transformed highs and lows.
A gap exposes another difference: with previous close 100, H = 111 and L = 109, the bar range is 2 but true range is max(2, 11, 9) = 11. The AB range ratio is 2 / 220, about 0.00909; it has no previous-close term. Its levels still move with H and L, but it does not directly measure the gap the way true range does. None of these formulas establishes a universal speed or profitability ranking.
Read the plotting example before adding signals
This existing example uses the public factor-4 calculation and a fixed 20-bar length. It draws three plots and a fill. It has no alert conditions, strategy orders, editable length input or explicit denominator guard. Use positive-price data with complete bars for formula comparison; do not treat the plot as a complete trading system.
// This source code is subject to the terms of the Mozilla Public License 2.0 at https://mozilla.org/MPL/2.0/
// © Pineify
//@version=6
indicator(title="Acceleration Bands", overlay=true, max_labels_count=500)
p_ta_ab(simple int length) =>
upper = ta.sma(high * (1 + 4 * (high - low) / (high + low)), length)
middle = ta.sma(close, length)
lower = ta.sma(low * (1 - 4 * (high - low) / (high + low)), length)
[upper, middle, lower]
[p_ind_1_upper, p_ind_1_middle, p_ind_1_lower] = p_ta_ab(20)
p_ind_1_upper_plot = plot(p_ind_1_upper, "AB - Upper", color.rgb(120, 123, 134, 0), 1)
plot(p_ind_1_middle, "AB - Middle", color.rgb(255, 152, 0, 0), 1)
p_ind_1_lower_plot = plot(p_ind_1_lower, "AB - Lower", color.rgb(120, 123, 134, 0), 1)
fill(p_ind_1_upper_plot, p_ind_1_lower_plot, title = "AB - Band", color=color.rgb(33, 150, 243, 95))In TradingView, open Pine Editor, paste the example and add it to a standard candlestick chart. Compare upper, middle and lower values in the Data Window on completed bars. Match symbol, timeframe, session, adjustment settings, length, factor and any display offset before comparing with another script. Similar-looking bands do not prove matching calculations.
Turn a verified rule into a Pine script
Pineify's Pine Script AI Coding Agent can create and edit Pine code from a written specification. Supply the public formula, valid-price assumptions, warm-up behavior and closed-bar rules together. Review the generated source and compare its numerical outputs in TradingView before adding alerts. A syntax check cannot establish signal quality or reproduce a proprietary indicator's hidden logic.
Example request: Build an Acceleration Bands indicator using the public factor-4 high/low formula with a 20-bar SMA. Reject nonpositive prices and invalid denominators, require a complete valid window, and expose the length as an input. Add separate markers for the first outside close and the second consecutive outside close. Evaluate only completed bars and emit the confirmation alert once per run. Show the band values for comparison.Build an Acceleration Bands script
Product access and usage limits depend on your plan. These examples are educational, not investment advice. No performance is claimed. Backtests need explicit exits, fills, costs and position sizing, and historical results do not guarantee future returns.
Acceleration Bands FAQ
Sources and related indicators
Sources reviewed October 17, 2026. Numeric examples are synthetic calculations, not measured trading results.