Calculate Fibonacci retracement and extension levels from price swings for technical analysis support and resistance identification.
A completed price swing becomes a set of horizontal price candidates when you enter its low, high, and direction. This calculator measures the high-to-low range, multiplies that range by the displayed percentages, and positions retracements inside the swing and extensions beyond it. It translates chart ratios into exact prices without measuring them by eye. The detail most often misread is the 50% line: it is commonly included in retracement grids, but one-half is not a Fibonacci ratio. Direction is also substantive; reversing it mirrors the calculated levels rather than merely changing a label.
A concrete input and expected output from the current implementation.
Input
Swing low: 100; swing high: 200; direction: up
Expected output
The returned 50% retracement level is 150.00.
The swing spans 100 price units. Half of that range is 50, so an upward retracement subtracts 50 from the 200 swing high, producing 150.
The calculator first treats the distance between the entered high and low as one full swing. For a rise, the retracement at decimal ratio r is high - (range x r); for a fall, it is low + (range x r). A 38.2% retracement therefore measures 38.2% back from the completed endpoint, not 38.2% upward from the lower price in both directions.
Extension percentages continue the measured range through the swing endpoint. On a rise, a 127.2% projection is low + (range x 1.272), which equals high + (range x 0.272). On a fall, the corresponding projection is high - (range x 1.272). Thus a 127.2% extension and a 27.2% move beyond the endpoint identify the same projected price in this two-anchor calculation.
Not in the strict mathematical sense. The 50% retracement is a charting convention placed alongside ratios such as 38.2% and 61.8%. The calculator can include it in the practical retracement grid, but its presence should not be read as a property of the Fibonacci integer sequence. It remains the exact midpoint of the chosen swing.
No. A level identifies a price derived from the selected anchors and ratio; it does not test volume, trend quality, volatility, news, liquidity, or whether the chosen swing was meaningful. A trader may compare the price with market structure and a risk plan, but the number alone supplies neither an entry signal nor a probability of reversal.
The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
Calculate gross, operating, and net profit margins from cost and revenue with breakeven analysis.
Convert between annual salary and hourly rate with adjustments for work hours, overtime, and benefits.
Calculate sales tax amounts, tax-inclusive and tax-exclusive prices for any tax rate or jurisdiction.
Calculate return on investment from initial cost and final value with annualized ROI and comparison tables.
Convert between markup and margin percentages, calculate selling price, and compare pricing strategies.
Convert numeric amounts to written words for invoices, checks, and legal documents in multiple currencies.