Fibonacci calculator
Generate Fibonacci retracement (38.2%, 50%, 61.8%) and extension levels between two points to find support, resistance and targets.
By the TradingCalculator.Pro team · Updated on · About us
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Formula
Level = High − (Range × Fib ratio)How it works
A Fibonacci retracement is a division of the move between two points. You take the swing high and low, subtract to get the range and discount the series percentages from the extreme: 23.6%, 38.2%, 50%, 61.8% and 78.6%. Extensions project beyond the extreme using the same ratios.
It helps to know what each number is. The 61.8% and 38.2% come from the golden ratio; 78.6% is the square root of 61.8%; and 50% is not a Fibonacci number at all, it is simply the midpoint, folded in by custom because it behaves similarly. None of the five has any power over price: what they have is a lot of people watching them at once, which in practice is enough.
What you get
- Automatic retracements and extensions
- Entry zones and targets
- Bullish and bearish
Worked example
An index rises from 4,200 to 4,650 points and starts to correct. Range = 4,650 − 4,200 = 450 points.
- 38.2% retracement: 4,650 − (450 × 0.382) = 4,478.10.
- 50% retracement: 4,650 − (450 × 0.50) = 4,425.00.
- 61.8% retracement: 4,650 − (450 × 0.618) = 4,371.90.
- 1.618 extension from the high: 4,650 + (450 × 0.618) = 4,928.10.
The 4,478 to 4,372 band is where the three usual retracements cluster; the extension target sits at 4,928.
A Fibonacci level is not an entry signal: it is a place to look. What turns 4,425 into a trade is something else lining up there — a moving average, a prior high, a shift in structure — plus a stop you can place below it at a ratio that works for you. Without that confluence and that stop, it is a pretty line.
How to use it
- Enter your inputs: the terms of the formula (capital, risk, prices and stop).
- The calculator applies the formula and returns the result in your instrument's units.
- Check the breakdown before trading: anything that cannot be computed is shown empty, never as zero.
Frequently asked questions
How do you calculate Fibonacci retracements on the Nasdaq?
Subtract the swing low from the swing high and discount the percentages from the extreme. On a 4,200 to 4,650 swing the range is 450 points and the 61.8% retracement lands at 4,650 − 278.10 = 4,371.90. In a downtrend you do the reverse: add from the low.
Which Fibonacci level is the most reliable?
None of them on its own; 61.8% and 50% are the most watched and therefore produce the most reactions. Their usefulness does not come from the golden ratio but from thousands of traders placing orders in the same zone, which makes them a partly self-fulfilling prophecy — and why they fail when the volume comes from somewhere else.
Why does 50% appear if it is not a Fibonacci number?
Because it is the midpoint of the move and custom folded it into the tool. It does not come from the 1, 1, 2, 3, 5, 8… series or the golden ratio: it is simply the halfway point, which Dow theory was already using long before. It stays because in practice it behaves much like the levels that do come from the series.
Where do I measure the swing from?
From one clear extreme to another of the move you want to measure, on the timeframe you are going to trade. That is where 90% of the tool’s subjectivity lives: two traders with the same chart and different swings get different levels, so what matters is fixing a rule — the last impulse on volume, say — and applying it the same way every time.
What are Fibonacci extensions for?
To project targets beyond the swing high or low, usually with the 1.272, 1.618 and 2.618 ratios. With a 450-point range from 4,650, the 61.8% extension gives 4,928.10. It is a statistical expectation for placing a target, not a prediction of price.