Fibonacci Calculator
Calculate reference levels from a chosen price swing. Enter the swing high, low and direction to get standard retracements and extensions. Choose extensions from the swing start (AB) or a correction endpoint (ABC). These are geometric levels; the calculation does not estimate the chance of a reversal or continuation.
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Retracements measure how far a counter-move pulls back into the prior swing; extensions project where a continuation could reach beyond it. The 61.8% ratio and the conventional 50% midpoint are included as reference levels. Their presence does not establish a reversal probability. Levels are an aid to planning, not financial advice.
How the Fibonacci calculator works
A Fibonacci grid is anchored to a single price swing – one clear move from a low to a high (or a high to a low). The vertical distance between those two points is the range, and each Fibonacci ratio marks a percentage of that range measured back from the end of the move.
In an uptrend you draw the grid from the swing low up to the swing high and read retracements downward from the high: a level is high − (high − low) × ratio. In a downtrend you draw from the swing high down to the swing low and read retracements upward from the low: low + (high − low) × ratio. Extensions use ratios above 100% to project a continuation beyond the original swing.
Worked example
EUR/USD rallies from a swing low of 1.1000 to a swing high of 1.1200 – a 200-pip range. In this uptrend the 61.8% retracement sits at 1.1200 − (0.0200 × 0.618) = 1.10764, and the 50% level at 1.1100. A reaction near this zone is only an observation. The AB 161.8% extension is 1.13236 (1.1324 rounded); any use as a target requires separate strategy rules and validation.
Which levels matter most
The 38.2%, 50% and 61.8% retracements are commonly used reference levels. The calculator does not measure order concentration there or establish that 61.8% separates a pullback from a reversal. Treat them as zones, not exact prices, and look for confluence with structure – see Fibonacci retracement and trend, support and resistance for the full method.
Frequently asked questions
Which two points do I use for the swing?
What is the difference between retracement and extension?
Why is 61.8% called the golden ratio?
Explicit AB or ABC reference point
Upward retracement: H − (H − L) × r; downward retracement: L + (H − L) × r. An upward AB extension starts at A = L: L + (H − L) × r; an ABC extension starts at correction endpoint C: C + (H − L) × r. For 1.1000 → 1.1200, the 61.8% retracement is 1.10764 and the AB 161.8% extension is 1.13236. With C = 1.1100, the ABC 161.8% extension is 1.14236. A downward swing reverses the sign. This form requires C inside the swing range. The 50% level is a charting convention, not a Fibonacci-sequence ratio. No level guarantees a reversal or continuation.
