Fibonacci Calculator [Free Tool]
Draw retracement and extension levels from any swing high and low in seconds. Use them as widely watched reference zones — not as guarantees of turning points.
Disclaimer: Trading financial instruments involves risk, and everything on this page is provided for educational purposes only. Nothing here is financial advice or a recommendation to buy or sell any instrument.
Retracement Levels
Extension Levels
How is this calculated?
Range = Swing High − Swing Low
Uptrend: Retracement = High − Range × level; Extension = Low + Range × level
Downtrend: Retracement = Low + Range × level; Extension = High − Range × level
Read the full user guide
Every parameter, formula, and worked example — a complete reference for this tool.
What are Fibonacci retracements and extensions?
Fibonacci retracements and extensions are horizontal levels drawn from a single swing high and swing low, spaced at the ratios that come from the Fibonacci sequence — 23.6%, 38.2%, 50%, and 61.8% among them. Retracement levels mark how far a move might pull back before resuming; extension levels project where it might run beyond the range. The tool is less about the math being magic and more about the fact that huge numbers of traders watch the same lines, which can make those zones behave like shared reference points.
Key concepts
Retracement
A pullback within a move, measured as a fraction of the original range.
Extension
A projection beyond the original range, used for targets.
Self-fulfilling levels
Levels are widely watched, which can make them act as psychological zones.
A worked example with real numbers
- 1
Pick the swing high and low
A stock rallied from $100 to $200. Your swing low is 100, your swing high is 200, so the range is $100.
- 2
Compute retracement levels
The 61.8% retracement sits at 200 − (100 × 0.618) = $138.20; the 38.2% level sits at $161.80.
- 3
Compute extension levels
The 161.8% extension projects to 200 + (100 × 0.618) = $261.80, a common target zone beyond the range.
- 4
Use them as zones, not promises
These levels mark where many traders watch for reactions. Price may pause there — or blow straight through.
How to use it
Enter swing high and low
The two extremes of the move you are measuring.
Choose direction
Up or down determines how levels are mapped.
Read levels
Retracement and extension prices for the range.
The formula, step by step
Retracement
Level = High − (High − Low) × ratio (downtrend)
Ratios: 0.236, 0.382, 0.5, 0.618, 0.786.
Mistakes traders make
✗ Trading a Fibonacci level as if it guarantees a reversal
✓The levels are reference zones watched by many participants, not turning points. Combine them with other evidence before acting.
✗ Choosing the swing points carelessly
✓Every level scales from your chosen high and low. Ambiguous swings produce meaningless levels — pick clear, obvious extremes.
✗ Stacking too many ratios until some level always 'works'
✓When you draw dozens of lines, price will touch something by chance. Restraint with a few meaningful ratios beats clutter.
When this tool fits — and when it does not
Use it when
- ✓Marking potential pullback zones after a clear impulsive move.
- ✓Projecting target areas beyond a range with extension ratios.
- ✓Adding confluence to levels that also match prior support/resistance or volume.
Skip it when
- ✗Trading a retracement level with no other confirming evidence.
- ✗Forcing Fibonacci onto a choppy, range-bound chart without an obvious swing.
- ✗Treating the ratios as having mystical or guaranteed predictive power.
Practical tips that actually help
Confluence is the whole game
A 61.8% retracement that lands exactly on old support and a volume node is far stronger than the ratio alone.
Use a few ratios, not every one
38.2%, 50%, 61.8% for retracements and 127.2%, 161.8% for extensions cover most practical needs.
Confirm before committing
Wait for price behavior at the zone — a rejection or a break with volume — rather than placing a limit order on the ratio by itself.
Related & next steps
Frequently asked questions
Do Fibonacci levels have statistical edge?▾
Their value is debated. They are best treated as reference zones watched by many participants, not guarantees of turning points.
Which two points should I use for the swing?▾
Use a clear, unambiguous swing high and swing low — the highest and lowest points of the move you are measuring. Picking meaningful extremes matters far more than the exact ratio math, because every level scales from those two anchors.
What is the difference between retracement and extension?▾
Retracement levels fall inside the original swing range and mark pullback depth. Extension levels fall beyond it and are used as projection targets, typically at 127.2% and 161.8%.
Why is 50% included when it is not a Fibonacci ratio?▾
It is a half-way point many traders treat as a natural retracement area, so charting tools include it by convention even though it is not derived from the sequence.
Should I trade a Fibonacci level on its own?▾
Almost never. A level is just a price zone. It becomes more meaningful when it lines up with other evidence — prior support or resistance, volume, or a pattern — rather than acting as a standalone buy or sell trigger.
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Fibonacci is a charting tool based on historical price ranges and is provided for educational purposes.
Disclaimer: The tools and content on this site are provided for educational purposes only and do not constitute investment advice. Trading and investing involve a substantial risk of loss, and past performance does not guarantee future results.