Levels & geometryGann Fan · Gann
A fan of angled lines from a pivot representing fixed price-per-time slopes, centered on the 1x1 (45-degree) line.
Works best in trending marketsEngine-computed on a fixed sample series
What it is
A Gann Fan is a set of straight lines drawn from a single important high or low, each rising or falling at a fixed rate of price per unit of time. It was devised by the early-20th-century trader W.D. Gann, who believed that price and time move in geometric proportion and that certain angles act as natural support and resistance. The centrepiece is the 1x1 line — one unit of price for every one unit of time — which on a correctly scaled chart sits at 45 degrees and is treated as the dividing line between a strong market and a weak one. Around it the fan spreads steeper lines (2x1, 3x1, 4x1, 8x1) and shallower ones (1x2, 1x3, 1x4, 1x8), so that price is always somewhere within a lattice of angled levels. The question it answers is simple to state: given where a major turn happened, at what rate should a healthy trend be advancing, and is the current market keeping up with, exceeding, or falling behind that pace?
How it is calculated
There is no averaging or oscillation here — the fan is pure geometry anchored to one pivot. You pick a significant swing high or low, decide a scale that ties one unit of price to one unit of time (for example one dollar per day), and draw the 1x1 line at that constant slope. The steeper lines multiply the price side: a 2x1 line rises two price units per time unit, a 4x1 line four, and so on, producing angles of roughly 63.75, 71.25, 75, and 82.5 degrees. The shallower lines multiply the time side: a 1x2 line advances one price unit per two time units, a 1x4 one per four, giving angles near 26.25, 18.75, 15, and 7.5 degrees. Everything therefore depends on the chosen scale — the price-to-time ratio must be fixed for the 45-degree premise to hold, which is why the same fan can look completely different if the chart's vertical scaling changes.
Reading it, step by step
The first read is always price versus the 1x1 line: above it Gann considered the market strong and biased up, below it weak and biased down. Each individual angle then acts as support in an uptrend and resistance in a downtrend, so as price rides above the 1x1 you watch it lean on that line and, if it breaks, expect it to seek the next shallower angle (1x2, then 1x3) as the trend loses pace. In a rising market that accelerates, price may climb from the 1x1 toward the steeper 2x1 and hold there, signalling an unusually powerful advance. Falling through a support angle is a downgrade of trend strength; reclaiming a lost angle is an upgrade. The fan is thus read as a ladder of trend-pace levels, with the 1x1 as the fulcrum and each break or reclaim shifting your read on how vigorously the move is unfolding.
Best timeframes and settings
Gann fans are traditionally a higher-timeframe, position-oriented tool, drawn on daily, weekly, and even monthly charts where major swing pivots are well defined and time units are unambiguous. The essential setting is not a period but the anchor and the scale: choose a genuinely significant high or low, and calibrate the price-per-time ratio so the 1x1 line meaningfully tracks the instrument's normal advance. On intraday charts the technique is far more fragile because the price-to-time scaling is arbitrary and shifts as you zoom. There are no smoothing parameters to trade responsiveness against noise; instead the trade-off is entirely in anchor selection — a fan hung from the wrong pivot is worthless, while one hung from a decisive turning point can frame months of price action. Because scaling drives everything, always fix the chart's aspect so the fan does not silently redraw when you resize.
When and where to use it
The fan is most defensible in clearly trending markets, where its angled supports and resistances behave much like a family of trendlines fanning out from a pivot. It suits liquid instruments with long, orderly histories — major indices, large-cap stocks, established FX pairs, and commodities Gann himself traded, like grains. In tight ranges or violently gapping markets the angles lose meaning because there is no coherent pace for them to describe. Many modern traders use the fan not as a mystical system but as a disciplined way to project trend-pace lines from a key turn, and treat confluence with conventional support, resistance, and moving averages as what actually matters. Avoid it if you need objective, reproducible levels, because the output is inseparable from subjective choices of anchor and scale.
Strategies that use it
Angle-bounce strategy: in an established uptrend, buy as price pulls back to and holds a fan support angle (often the 1x1), with a stop just below that line and a target at the next steeper angle above. Break-and-retest strategy: when price decisively breaks below the 1x1, treat it as a trend-weakness signal, wait for a failed retest of the underside of the line, and sell toward the next shallower angle as the new resistance. Acceleration strategy: if a strong trend lifts price off the 1x1 and it begins holding the steeper 2x1, ride the faster leg while price respects that angle and exit when it slips back to the 1x1. In every case the angle you are trading against defines your invalidation level, which keeps risk tightly framed even though the tool itself is interpretive.
Combining it with other indicators
Because Gann angles are subjective, confluence is essential — the strongest fan levels are those that coincide with horizontal support and resistance, prior swing highs and lows, or round numbers. Overlaying Fibonacci retracements often reveals price zones where a fan angle and a Fibonacci level nearly meet, and those overlaps deserve far more attention than either alone. A moving average or two adds an objective trend read that can confirm whether the 1x1 break is echoed by momentum turning over. Volume is a valuable partner at angle tests: a bounce off a fan support on rising volume is more trustworthy than one on fading participation. Pairing the fan with an oscillator such as RSI lets you demand momentum agreement before acting on a break of the 1x1, filtering out the many angle touches that lead nowhere.
Where it fails
The deepest flaw is scale dependence: because the 45-degree premise relies on a fixed price-to-time ratio, the identical fan looks different on another platform, timeframe, or zoom level, so the same trade can appear valid or invalid depending on your settings. The method is also easy to curve-fit after the fact — with nine angles radiating from a pivot, price will always be near some line, which invites the illusion that the fan is predictive when it is merely dense. A poorly chosen anchor produces meaningless levels, and there is no objective rule for which high or low to use. In fast, news-driven markets price can slice through several angles at once, rendering the ladder useless for that move. The remedy is to treat the fan as a framing device rather than a signal generator, insist on confluence with objective levels, and lock the chart scale so the geometry stays honest.
A worked example
Suppose a stock bottoms at 100 and you anchor a fan there, scaling one dollar of price to one trading day so the 1x1 line rises exactly one point per day. Ten days later the 1x1 line sits at 110, the steeper 2x1 line at 120, and the shallower 1x2 line at 105. If price on that day is trading at 112, it is comfortably above the 1x1 line — Gann's read is a strong, healthy uptrend, and you would look to buy pullbacks toward 110 with a stop just under it. Imagine price then stalls and, five days on, closes below the 1x1 line, which by then is at 115. That break downgrades the trend, and you would expect price to gravitate toward the next shallower support, the 1x2 line, which by that day has risen only to about 107.5. A trader watching the fan would exit longs on the 1x1 break and either stand aside or look for a bounce at the 1x2 angle, using that line as the level to risk against.