Fibonacci Retracements and Extensions

What you will learn

• How to choose the swing points for a Fibonacci tool.
• How to calculate retracement levels by hand.
• How extension levels are projected beyond a swing.
• Why Fibonacci levels are confluence tools, not magic numbers.

Explanation

Fibonacci ratios come from a number sequence in which each number is the sum of the two before it (1, 1, 2, 3, 5, 8, 13...). Ratios between these numbers approach 0.618. Traders use levels such as 38.2%, 50% and 61.8%. The 50% level is not a Fibonacci ratio but is usually included.

Retracements

A retracement is a pullback against the last move. In an uptrend you draw the tool from the swing low to the swing high. A level is: swing high − (range × ratio). The range is swing high minus swing low.

Extensions

An extension projects levels beyond the swing, for possible targets. Conventions differ between platforms. A simple version uses the same range from the swing low: level = swing low + (range × ratio), with ratios such as 127.2% and 161.8%. Always check how your own platform defines them.

How to choose swing points

Use clear, confirmed swing points from your structure rules (lesson 2), on the timeframe you analyse. If you choose different swings, you get different levels. Choosing swings until the levels "fit" past reactions is a form of hindsight.

Why not magic

There is no reliable proof that markets "respect" Fibonacci ratios more than other levels. With five levels on a chart, price will often react near one of them by chance. Their value comes from confluence: when a Fibonacci level overlaps with a demand zone, a previous swing level or a moving average, the area has several independent reasons to matter. Some of the effect may also be self-fulfilling, as discussed in lesson 1.

Worked example

Hypothetical example: a share in €. Swing low €100, swing high €140, uptrend confirmed. Fees, spreads and taxes are excluded.

1. Range: €140 − €100 = €40
2. 38.2%: €140 − (€40 × 0.382) = €140 − €15.28 = €124.72
3. 50%: €140 − (€40 × 0.5) = €140 − €20 = €120.00
4. 61.8%: €140 − (€40 × 0.618) = €140 − €24.72 = €115.28

Extensions (convention measured from the swing low):

1. 127.2%: €100 + (€40 × 1.272) = €100 + €50.88 = €150.88
2. 161.8%: €100 + (€40 × 1.618) = €100 + €64.72 = €164.72

Confluence check: there is a demand zone from €118.50 to €121.00 and a previous swing high at €120. The 50% level (€120) sits inside both. This area is more interesting than the 38.2% level, which has no other support. The trader still waits for a bullish break of structure on the entry timeframe.

Common mistake

Practice activity

Hypothetical index in points: swing low 2,000, swing high 2,400. Calculate the 38.2%, 50% and 61.8% retracements. Then a demand zone sits at 2,140 to 2,170. Which level has confluence?

Key takeaways

• Retracement level = swing high − (range × ratio) in an uptrend.
• Extension conventions differ; check your platform.
• Use confirmed swing points; do not adjust them to fit.
• Fibonacci levels matter most when they overlap with other evidence.

Next step

In the final lesson you will test a complete setup: write rules, record results in R, and avoid curve-fitting and look-ahead bias.