Bollinger Bands vs Keltner Channels: What Is the Difference?

Bollinger Bands vs Keltner Channels

Bollinger Bands take their width from the standard deviation of closing prices; Keltner Channels take theirs from Average True Range, which counts gaps. So Bollinger width spikes and collapses faster on a few extreme closes, while Keltner width changes gradually and holds steadier through a trend. Bollinger’s documented defaults are a 20-period simple moving average with bands 2 standard deviations out; Keltner commonly uses a 20-period exponential moving average with a factor of 2.

Bollinger Bands vs Keltner Channels
	Bollinger BandsBollinger Bands	Keltner ChannelsKeltner Channels
Center Line	Simple moving average, 20 periods by default	Moving average, commonly a 20-period EMA
Width Input	Standard deviation of closing prices	Average True Range of full bar ranges
Formula	SMA(n) ± k × standard deviation(n), default k = 2	EMA(n) ± m × ATR(p), default m = 2, p about 10 to 14
Treatment of Gaps	Ignored unless the gap changes closing prices	Captured, since true range uses the prior close
Reaction to One Outlier Bar	Sharp, a single extreme close can flare the bands	Muted, one wide bar is averaged into the ATR
Behavior in a Sustained Trend	Often flares open, then contracts while price grinds on	Tracks the advance at a more stable width
What a Band Touch Tells You	Price is statistically stretched versus recent closes	Price has reached the selected ATR distance from the center line
Common Width Read	Bandwidth, (upper − lower) / middle, for squeezes	Channel width in ATR terms, also used for stop sizing

Bollinger BandsBollinger Bands

Keltner ChannelsKeltner Channels

Center Line

Simple moving average, 20 periods by default

Moving average, commonly a 20-period EMA

Width Input

Standard deviation of closing prices

Average True Range of full bar ranges

Formula

SMA(n) ± k × standard deviation(n), default k = 2

EMA(n) ± m × ATR(p), default m = 2, p about 10 to 14

Treatment of Gaps

Ignored unless the gap changes closing prices

Captured, since true range uses the prior close

Reaction to One Outlier Bar

Sharp, a single extreme close can flare the bands

Muted, one wide bar is averaged into the ATR

Behavior in a Sustained Trend

Often flares open, then contracts while price grinds on

Tracks the advance at a more stable width

What a Band Touch Tells You

Price is statistically stretched versus recent closes

Price has reached the selected ATR distance from the center line

Common Width Read

Bandwidth, (upper − lower) / middle, for squeezes

Channel width in ATR terms, also used for stop sizing

What is the difference between Bollinger Bands and Keltner Channels?

Bollinger Bands and Keltner Channels draw the same shape: a center line with an upper and a lower line that widen when markets get busier and narrow when they quiet down. The difference is what supplies the width. Bollinger Bands use the standard deviation of closing prices, so they measure how scattered the closes have been. Keltner Channels use Average True Range, so they measure how much ground the bars have covered, gaps included.

Bollinger Bands take the standard deviation of closing prices over the same window as the center line and multiply it by a factor. The documented defaults are a 20-period simple moving average with bands two standard deviations above and below, and Fidelity lists 10 periods with 1.5 standard deviations for short-term work and 50 periods with 2.5 for long-term work. The formula is SMA(n) plus or minus k times the standard deviation over n.

Keltner Channels take Average True Range and multiply it by a factor. The modern default most traders see is a 20-period exponential moving average with a factor of 2, with ATR measured over roughly 10 to 14 periods. True range for a bar is the greatest of the high minus the low, the absolute value of the high minus the prior close, and the absolute value of the low minus the prior close. That prior-close term is why ATR registers gaps and standard deviation of closes does not.

The word modern matters here. Chester Keltner’s original construction centered a simple moving average of typical price, (high + low + close) / 3, and drew band width from an average of the high-low range with no ATR multiplier. Fidelity still documents that version under the name Keltner Bands. Charting platforms later shifted to the EMA and ATR form, so a study labeled Keltner Bands and one labeled Keltner Channels can plot different lines on the same chart.

How Bollinger Bands and Keltner Channels differ in practice

Run the worked numbers side by side. In the Bollinger example, a 20-period SMA at $80 with a 20-period standard deviation of $2.50 and a two-standard-deviation setting puts the upper band at $80 + (2 × $2.50) = $85 and the lower band at $75, a normalized bandwidth of ($85 − $75) / $80 = 12.5%. In the Keltner example, a 20-period EMA at $100.10 with a 10-period ATR of $0.45 and a 2.0 multiplier puts the upper channel at $100.10 + (2.0 × $0.45) = $101.00 and the lower channel at $99.20, a width of $1.80 or about 1.8% of price.

Standard deviation is the square root of the average squared distance from the mean. Large closing-price deviations increase Bollinger width. ATR averages true ranges, including gaps, to set Keltner width. Compare the two to distinguish dispersion in closing prices from the size of individual trading ranges.

That is also why the standard compression reading works. When the Bollinger Bands contract inside the Keltner Channels, dispersion of closes has fallen faster than average bar range. The break out of the squeeze picks the direction.

When to use Bollinger Bands vs Keltner Channels

Start with the regime, not the indicator. In a rotating market with a flat center line, the faster envelope is more informative, because Bollinger Bands mark the moments closes have stretched furthest from their own mean and percent B quantifies location inside the envelope. In a trending market, the steadier envelope is more informative, because a Keltner Channel keeps a usable outer reference while price walks it rather than snapping open and shut.

Use the width measurement to set a price distance, then size the position to the trade budget. With a $500 budget and a $2 stop distance, the planned size is 250 shares. If the stop distance rises to $4, reduce the size to 125 shares. ATR and standard deviation both provide price-distance measures; position size determines the dollars allocated to that distance.

Before buying options on a squeeze, check the chain: the envelopes measure what price has done, and implied volatility sets what the option costs. A contract that already prices a large expected move stays expensive however narrow the bands get.

Whichever you use, fix the inputs before testing anything. Price source, average type, lengths, and multiplier all change the signals on identical data, and searching across those settings for the best historical result fits the sample rather than describing a durable effect.

Bottom line

Bollinger Bands measure dispersion of closes and react fast, while Keltner Channels measure typical bar travel including gaps and react smoothly. Use Bollinger Bands to find compression and stretch inside a range, Keltner Channels for trend context and ATR-scaled risk, and the two together for the squeeze reading. Both measure what price has already done, so pair them with levels, volume and the option chain before you trade the break.

Bollinger Bands vs Keltner Channels: FAQ

Which is better, Bollinger Bands or Keltner Channels?

Bollinger Bands fit a range and Keltner Channels fit a trend. Bollinger Bands describe dispersion of closes and react faster, which suits compression and mean-reversion work in a range. Keltner Channels describe average bar travel and hold a steadier width, which suits trend context and ATR-based risk sizing. Many traders plot both. Pick by the regime you are trading and the rule you are testing.

What is the Bollinger Band and Keltner Channel squeeze?

A widely used compression reading calls a squeeze when the Bollinger Bands contract entirely inside the Keltner Channels. That happens when the dispersion of closes has fallen faster than average bar range, which is a compact way to say recent trading has been unusually quiet. Trade it as a setup: mark the levels on both sides and let the break through one of them pick the direction and the entry.

Why do Bollinger Bands and Keltner Channels use different moving averages?

Bollinger Bands are documented with a simple moving average so the center line and the standard deviation are computed from the same equally weighted window. Keltner Channels are most often drawn with an exponential moving average, which weights recent bars more heavily and turns faster after a directional move. Both are configurable inputs on charting platforms, and a 20-period EMA center line and a 20-period SMA center line will disagree during fast reversals.

Do Keltner Channels handle overnight gaps better than Bollinger Bands?

They capture gaps by construction. True range is the greatest of the high minus the low, the absolute value of the high minus the prior close, and the absolute value of the low minus the prior close, so an overnight gap enters the calculation directly. Bollinger Bands see a gap only through its effect on closing prices. That is an advantage for intraday and post-earnings work, but it cuts both ways, because a gap inflates ATR and widens the channel even when the trading that follows is quiet.

Can you use Bollinger Bands and Keltner Channels together?

Yes, and the combination is the most common use of the pair. Plot both around a comparable average, read compression when the Bollinger Bands sit inside the Keltner Channels, and use the Keltner center-line slope for direction and the ATR value for stop distance. Both are transforms of the same price history, so confirm the read with structure, volume and the option chain, which supply the information neither envelope contains.