Bollinger Bands explained for forex and gold

Bollinger Bands are one of the few indicators that sit directly on the price chart rather than in a panel underneath it. Three lines wrap around price: a moving average in the middle and two bands that widen when the market is busy and narrow when it goes quiet. They look simple, and that is exactly why they are often misread. A touch of the upper band is not automatically a reason to sell, and a touch of the lower band is not automatically a reason to buy.

This guide explains how the bands are calculated, what each line tells you, how the squeeze and band walking work, and how to use the tool on currency pairs and on gold without turning it into a vending machine for trades.

What Bollinger Bands are

Bollinger Bands were developed by John Bollinger in the 1980s. The idea is to show where price sits compared with its own recent average and its own recent volatility. Instead of using a fixed distance, such as 50 pips above and below an average, the bands use standard deviation, a statistical measure of how spread out recent prices are. When prices swing widely, the standard deviation rises and the bands move apart. When prices are calm, it falls and the bands come together.

That makes the bands adaptive. The same settings work on a slow pair during the Asian session and on gold during a busy New York morning, because the width adjusts to each market. Three things are worth keeping in mind from the start:

• The bands describe, they do not predict. They are built from past closes, like every moving average.
• High is relative. Price at the upper band is high compared with the last 20 candles, not high in any absolute sense.
• Width is information. How far apart the bands are often tells you more than where price sits inside them.

How Bollinger Bands are calculated

Your platform does the maths, but knowing the steps explains how the bands behave.

1. The middle band. A 20 period simple moving average of the closing price.
2. The standard deviation. Measure how far the last 20 closes are spread around that average.
3. The upper band. The middle band plus two standard deviations.
4. The lower band. The middle band minus two standard deviations.

Here is a short example with made up numbers, not live market data. Suppose the 20 day average on EUR/USD is 1.1000 and the standard deviation of the last 20 closes is 0.0040, or 40 pips. The upper band is 1.1000 plus 80 pips, which is 1.1080. The lower band is 1.1000 minus 80 pips, which is 1.0920. The bands are 160 pips apart. On gold, a 20 day average of 4,100 dollars with a standard deviation of 30 dollars gives bands at 4,160 and 4,040, a gap of 120 dollars, or about 2.9% of price.

In a perfectly normal distribution about 95% of values would fall within two standard deviations. Market prices are not that tidy, so in practice the share of closes inside the bands is usually a little lower, and it changes from market to market. The point is not the exact percentage but the idea that closes outside the bands are unusual compared with recent behaviour.

Reading the three lines

The middle band

The middle band is a 20 period moving average, so it works as a simple trend guide. When price holds above a rising middle band, the short term trend is up. When it holds below a falling one, the trend is down. In trends, pullbacks often stall around the middle band, which is why many traders watch it as a dynamic area rather than a precise line. Our guide to trends and moving averages covers the basics.

The upper and lower bands

The outer bands mark the edges of recent normal movement. A close near the upper band means buyers have pushed price to the high end of its recent range. A close near the lower band means sellers have done the same on the other side. On their own, these touches are context, not signals. What happens next depends on whether the market is ranging or trending.

Band width

Band width is the distance between the upper and lower bands, often shown as a percentage of the middle band so it can be compared over time. Narrow bands mean low volatility; wide bands mean high volatility. Volatility tends to move in cycles, so very narrow bands often come before a period of larger moves, and very wide bands often come before things calm down again.

The squeeze: quiet before the move

A squeeze is a period when the bands pinch unusually close together. It tells you the market has gone quiet compared with its own recent history. Because calm periods rarely last forever, a squeeze is often followed by an expansion, a sharp move that pushes the bands apart again.

The squeeze has one big limitation: it does not tell you the direction. Price can break out higher or lower, and the first push is sometimes a false start that reverses before the real move. Many traders therefore treat the squeeze as a warning to pay attention rather than a reason to enter. They wait for a clear close outside the bands, or a break of a nearby support or resistance level, before acting, and they keep the position small because breakouts fail regularly.

The squeeze is also relative. Band width that counts as narrow for gold would be very wide for EUR/USD. Compare the current width with the same market's own recent range of widths, not with a fixed number.

Walking the bands in a trend

One of the most common mistakes is selling every touch of the upper band. In a strong uptrend, price can close at or above the upper band again and again, while the middle band keeps rising underneath. Bollinger himself described this as walking the bands. The same happens in reverse in a strong downtrend, with price hugging the lower band.

A few signs suggest a trend is walking the band rather than about to reverse:

• The bands are widening, not narrowing.
• The middle band is clearly sloping in the direction of the move.
• Pullbacks stop around the middle band and then push back toward the outer band.

In that environment, fading the band means trading against momentum. A more cautious approach is to wait for price to close back inside the bands and fail to return to the outer band before treating the move as tired.

Mean reversion in ranges

When a market is moving sideways, the middle band is roughly flat and the bands are fairly steady in width. Here the classic idea can work better: price stretches to one band, runs out of steam and drifts back toward the middle. Traders who use this approach usually look for extra confirmation, such as a clear support or resistance level at the band, a rejection candle, or a momentum reading from a tool like RSI.

The weakness of mean reversion is that every trend starts as a break out of a range. The trade that fades the upper band works until the day it does not, and that day can be expensive if there is no stop. Our guide to support and resistance explains how to find the levels that make these ideas more meaningful.

Two useful extras: %B and band width

Some platforms offer two indicators built from the bands. %B shows where price sits inside the bands on a simple scale. It is calculated as price minus the lower band, divided by the upper band minus the lower band. A reading of 1 means price is on the upper band, 0 means it is on the lower band, and 0.5 means it is on the middle band. Readings above 1 or below 0 mean price has closed outside the bands. In the EUR/USD example above, a price of 1.1040 with bands at 1.0920 and 1.1080 gives a %B of 120 divided by 160, which is 0.75.

Band width turns the gap between the bands into one line, which makes squeezes and expansions easy to spot over a long history. Both tools contain the same information as the bands themselves, just presented in a form that is easier to scan.

Choosing Bollinger Bands settings

The standard 20 period average with two standard deviations is a sensible default and the one most traders look at. If you change the number of periods, Bollinger suggested adjusting the multiplier as well: about 1.9 standard deviations for a 10 period average and about 2.1 for a 50 period average, so the bands still contain a similar share of price action.

Shorter settings react faster but produce more touches that mean little. Longer settings are smoother but slower. As with any indicator, pick a setting, keep it fixed while you test it on past charts, and judge it on a decent number of examples rather than a few memorable ones.

Bollinger Bands on forex pairs and on gold

On major currency pairs the bands are usually measured in tens of pips on the daily chart. They tend to be narrow during quiet sessions and widen around the London open, the New York open and major releases such as inflation data or central bank decisions. A single large candle on a news release can widen the bands sharply for the next 20 periods, so a squeeze that ends on a data release is worth treating with extra care. Our guide to London and New York trading sessions explains when activity usually picks up.

Gold (XAUUSD) often trends harder and moves further than most currency pairs, so its bands are much wider in dollar terms, and walking the band is common during strong moves. Because a few dollars on gold is a lot of money per lot, a trade idea taken from a band touch needs the stop and position size worked out first. The lot size calculator helps you size a trade from the stop distance, and our guide to the ATR indicator shows how to set stops that respect normal volatility.

Common Bollinger Bands mistakes

1. Selling every upper band touch. In strong trends price can ride the band for a long time.
2. Treating the squeeze as a direction signal. It warns that a move may come, not which way.
3. Ignoring the middle band. Its slope tells you whether you are in a range or a trend, which changes how a touch should be read.
4. Comparing width across markets. Gold's normal band width would look extreme on a major currency pair.
5. Placing stops on the band itself. The bands move every candle and price often pokes through them, so a stop exactly on a band is easy to hit.

A simple Bollinger Bands checklist

• Check the slope of the middle band to judge whether the market is ranging or trending.
• Check band width compared with its own recent history: narrow, normal or wide.
• In a range, look for band touches at clear support or resistance, with confirmation.
• In a trend, look for pullbacks toward the middle band rather than fading the outer band.
• Treat a squeeze as a warning and wait for a decisive break before acting.
• Set the stop where the idea is wrong, then size the position from that distance.

Using Bollinger Bands alongside trade signals

If you follow signals, the bands can give you context rather than replace the plan. Forexuro signals come with an entry, a stop loss and three targets, and every closed trade is listed in the public trade history, losses included. A quick look at the bands when a signal arrives can show whether the trade is joining a market that is expanding, sitting in a quiet squeeze, or stretched far from its average. Whatever the chart shows, the stop and the position size in the plan still come first, and our guide to lot size calculation walks through the arithmetic.

Official sources

Primary reference pages from regulators, central banks and official bodies on the topics in this article.

• BIS: Triennial Central Bank Survey of foreign exchange markets, 2025, the global data on foreign exchange turnover by currency and trading centre.
• LBMA Gold Price, the London benchmark price for gold in US dollars per troy ounce.
• FCA: permanent restrictions on the sale of CFDs to retail consumers, the UK leverage limits, margin close-out rule, negative balance protection and risk warnings for retail CFD trading.

Frequently asked questions

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