Fibonacci Extension Calculator

Project target levels beyond a completed swing using the standard extension ratios and a retracement point.

A Fibonacci extension calculator projects levels beyond a completed swing using three points. A is where the measured move began, B is where it ended, and C is how far the price came back before the projection is made. The distance from A to B is the unit, and each of the fib extension levels is a multiple of that distance measured from C — not from B, and not from A. That choice of anchor is the whole character of the tool, and it is the thing most often got wrong when two people compare their charts.

Formula: extension = retracement point + (swing range x extension ratio)

Your figures

Which way the swing ran

This sets the order the three points must fall in, and which side of C the levels are projected onto.

Swing start (A)

Where the measured swing began.

Swing end (B)

Where it ended. The distance from A to B is what every ratio is a multiple of.

Retracement point (C)

How far the price came back before the projection is made. It must sit between A and B — the levels are projected from here, not from B.

Extra ratio

Optional — adds one more projection at a ratio of your own, such as 313%. Ratios already in the table are not repeated.

Current price

Optional — reports the gap from your price to each projected level.

Extension levels

161.8% extension level

144.36

1.618 × a 20.00 swing, projected from C — the full table is below

61.8%1.64 below your price · -1.30%: 124.36
100%6.00 above your price · +4.76%: 132.00
127.2%11.44 above your price · +9.08%: 137.44
161.8%18.36 above your price · +14.57%: 144.36
200%26.00 above your price · +20.63%: 152.00
261.8%38.36 above your price · +30.44%: 164.36
423.6%70.72 above your price · +56.13%: 196.72
Swing measured (A → B)Read as upswing, so the levels are projected above C.: 100.00 → 120.00
Swing rangeThe distance from A to B. Each ratio is a multiple of this.: 20.00
Retracement depth8.00 back from B to 112.00. 0% would be at B, 100% back at A.: 40.00%
Nearest level above your price6.00 above the price you entered.: 100% · 132.00
Nearest level below your price1.64 below the price you entered.: 61.8% · 124.36
Levels either sideCounted against the price of 126.00 you entered.: 6 above · 1 below

What this means

The swing from 100.00 to 120.00 measures 20.00, and it came back 8.00 to 112.00 — 40.00% of the way. The 161.8% level therefore falls at 144.36: point C plus 1.618 × 20.00. Projecting from C rather than from B is what makes this an extension rather than a plain multiple of the swing: the same A-to-B distance projected from a shallow pull-back lands somewhere quite different from the same distance projected from a deep one, which is why the depth is reported beside the levels. The price you entered, 126.00, sits between 61.8% at 124.36 and 100% at 132.00. Each row is the price at which a projected multiple falls. Nothing in the arithmetic makes one of them more likely to be reached than any other price.

The levels are projected from C, so moving C moves all of them. Two people who agree on A and B but pick different retracement points get different tables from the same swing.
127.2% is the square root of 1.618 and 423.6% is 1.618 to the fourth power. 100% and 200% are whole multiples of the swing rather than ratios from the sequence, included for the same reason 50% appears on a retracement table.
The whole table depends on which points you measured between. Two people reading the same chart and picking different swings get different levels, and neither of them has made an arithmetic error.
A level is a price a formula produces from figures that have already printed. Reaching one is not evidence that it holds, and nothing on this page is a view on which way the next period goes.
Nothing is fetched. Every figure above is one you typed, which is what lets the same calculator serve this morning's bar, a weekly bar from years ago, and an instrument no data provider covers.

The link reopens this calculator with the same numbers. Nothing you enter is sent to a server.

Continue with these figures

About the Fibonacci Extension calculation

Because a Fibonacci projection calculator of this kind measures the levels from C, moving C moves all of them by exactly the same amount. Two people who agree completely on where the swing ran but disagree about where the pull-back finished will produce tables offset from one another point for point. On a 20-point swing, taking C at 112 rather than 104 shifts the 161.8% level from 136.36 to 144.36 — the eight-point difference in C carried straight through, with the ratio and the range identical in both.

The ratios are powers and roots of the golden ratio. 161.8% is φ itself, 261.8% is φ squared, 423.6% is φ cubed and 127.2% is the square root of φ. 100% and 200% are whole multiples of the swing rather than anything from the sequence, and they are included for the same reason 50% appears on a retracement table: charting packages draw them, and a table that left them out would disagree with the reader's screen.

Levels of this kind are conventionally called targets, and platforms that ship a Fibonacci target calculator mean exactly this table by it. The word is a naming convention rather than a statement about where the price goes: each row is the price at which a projected multiple falls. Nothing in the calculation makes the 1.618 extension target, or any other row, more likely to be reached than any other price, and the calculator says nothing about whether the move continues at all.

Fibonacci Extension formula

range = |B − A|
depth = |B − C| ÷ range × 100

upswing    (A ≤ C ≤ B)   level(r) = C + (r ÷ 100) × range
downswing  (B ≤ C ≤ A)   level(r) = C − (r ÷ 100) × range

standard ratios r = 61.8, 100, 127.2, 161.8, 200, 261.8, 423.6

A: The swing start — where the move being measured began. It sets one end of the unit distance and takes no further part in the projection.
B: The swing end — where that move finished. A and B cannot be the same price, because there would be no range to project.
C: The retracement point, where the pull-back finished. Every level is measured from here, so this is the input the whole table hangs on.
range: The absolute distance from A to B. Each ratio is a multiple of this figure, which is why a wide swing gives a widely spaced table.
depth: How far the price came back from B towards A, as a percentage. 0% would be at B with no pull-back at all; 100% would be all the way back at A.

Projecting from C rather than from B is what makes this an extension rather than a plain multiple of a swing. The same A-to-B distance projected from a shallow pull-back lands somewhere quite different from the same distance projected from a deep one, and the depth of the pull-back is reported beside the levels so that dependence is visible rather than buried in the output. A 20-point swing projected at 161.8% from a C that gave back 8 points reaches 144.36; from a C that gave back 16 points it reaches 136.36.

This is also the single largest reason two platforms show different extension levels for the same three prices, and it is worth being precise about. Some tools are two-point: they take only A and B, and draw levels beyond 100% of that swing measured from A. Others are three-point, take A, B and C, and project from C — which is what this calculator does. On A = 100, B = 120, C = 112, the three-point 161.8% level is 144.36 while the two-point one is 100 + 1.618 × 20 = 132.36. Both are labelled 161.8%; they are more than twelve points apart. Before deciding that one of them is wrong, check how many points the other tool asked you for.

The ordering of the three points is the whole of the validation, and the calculator names whichever point is out of place rather than reporting that the inputs are invalid. An upswing runs A up to B and comes back to C, so A ≤ C ≤ B must hold. A downswing runs A down to B and comes back up to C, so B ≤ C ≤ A. With three prices on screen, being told simply that something is wrong leaves the reader to work out which box to change, which is why each rule has its own sentence.

The ratios come from the golden ratio rather than from the sequence directly. φ is 1.618, and its square is 2.618 and its cube 4.236 — which is where 161.8%, 261.8% and 423.6% come from. 127.2% is √φ, the geometric halfway point between the swing repeating once and repeating 1.618 times. 100% is the swing repeated exactly from C, which is the classic measured move and is not a Fibonacci quantity at all, and 200% is it repeated twice.

A depth of exactly 0% or exactly 100% is permitted rather than rejected. At 0% the price never pulled back and C sits on B, so the projection is measured from the swing end and the table becomes the plain multiple case. At 100% the entire move has been given back and C sits on A, so the 100% level lands exactly back on B. Both are legitimate arithmetic, and both are worth recognising when they appear, because a table drawn from a swing that fully retraced is describing something different from one drawn from a shallow pull-back.

Fibonacci Extension: a worked example

An upswing from A at 100 to B at 120 that pulled back to C at 112, with 126 entered as the current price and the standard extension ratios drawn.

Swing range|120 − 100| = 20.00
Retracement depth|120 − 112| = 8.00, which is 8 ÷ 20 = 40.00%
61.8%112 + 0.618 × 20 = 124.36
100%112 + 1.000 × 20 = 132.00
127.2%112 + 1.272 × 20 = 137.44
161.8%112 + 1.618 × 20 = 144.36
261.8%112 + 2.618 × 20 = 164.36
Where 126 sitsbetween 61.8% at 124.36 and 100% at 132.00

Seven projected levels running from 124.36 up to 196.72, with the 161.8% level at 144.36 and the price entered sitting between the two lowest of them. The 40% depth is doing real work in those figures: had the pull-back reached 104 rather than 112, the depth would have been 80% and the same 161.8% ratio would have landed at 136.36. The projection is arithmetic on three prices that have already printed, and it carries no information about whether any of these levels is reached.

How to use the Fibonacci Extension calculator

Set the direction first, because it decides the order the three points must fall in and which side of C the levels are projected onto.
Enter A and B as the two ends of the move you are measuring. The distance between them is the unit that every ratio multiplies, so this is what sets the spacing of the whole table.
Enter C as the point the pull-back reached. It has to sit between A and B, and it is what every level is measured from — this is the input to be most careful about.
Read the retracement depth row alongside the levels. A shallow pull-back and a deep one produce very differently placed tables from the identical swing, and the depth is what tells you which you are looking at.
Add an extra ratio if your platform draws one this table does not, such as 313%. It appears in ratio order and is marked as yours.
Enter a current price to see the gap from it to each projected level. It changes nothing in the projection and is reported as a distance only.

Limitations of the Fibonacci Extension calculator

Every calculation makes assumptions. These are the ones that matter here.

The table depends on three chosen prices rather than two, so it carries all the ambiguity of a retracement plus the further question of where the pull-back finished.
A two-point extension tool and a three-point one produce different levels from the same swing, so figures from here only match a platform that also projects from the retracement point.
Nothing in the arithmetic makes a projected level more likely to be reached than any other price. These are multiples of a distance, drawn forward from a point that has already printed.
100% and 200% are whole multiples rather than Fibonacci ratios, and are drawn only because charting packages draw them. Reading them as though the sequence produced them would be a mistake.
The projection assumes a linear price scale. The same three points measured on a logarithmic chart give different levels, and the gap widens as the projected multiples grow.
Levels far out in the table — 261.8% and 423.6% of the swing — are a long way from any price that has actually traded, and small errors in A, B or C are magnified in proportion to the ratio.

Frequently asked questions about Fibonacci Extension

Why are the levels measured from C rather than from B?

Because that is what distinguishes a three-point extension from a plain multiple of the swing. The tool is describing a move that ran, pulled back, and is being projected onward from where the pull-back finished, so the anchor is the pull-back. It also means C is the most consequential input: shifting it by a point shifts every level in the table by exactly a point.

Why does my charting package show a different 1.618 extension target?

Most often because it is using a two-point tool. A two-point extension draws levels beyond 100% of the A-to-B swing measured from A, so on A = 100 and B = 120 its 161.8% level is 132.36. This three-point tool projects from C, so with C at 112 its 161.8% level is 144.36. Both are labelled the same way and neither is miscalculated — check how many prices the other tool asked you for.

What does the retracement depth percentage tell me?

How far back towards A the price came before the projection was made, on a scale where 0% is at B and 100% is back at A. It is reported next to the levels because the projection is measured from C, so the depth is what determines where the whole table sits. Two swings with identical ranges but different depths produce tables offset by the difference between their retracement points.

Where does 423.6% come from?

It is the golden ratio cubed: 1.618 × 1.618 × 1.618 is 4.236. In the same way, 261.8% is φ squared and 127.2% is the square root of φ. 161.8% is φ itself, which is the ratio the Fibonacci sequence converges on as its terms grow. The remaining two standard ratios, 100% and 200%, are simply the swing repeated once and twice.

Can the retracement point sit outside A and B?

No, and the calculator says which of the three points is out of place rather than reporting a generic error. For an upswing the ordering A ≤ C ≤ B has to hold; for a downswing it is B ≤ C ≤ A. If the price has gone beyond A, the entire measured move has been given back, and a projection built on it would be describing a swing that no longer exists in the form it was measured.

Is a 161.8% level a price target?

It is conventionally called one, which is a naming habit rather than a claim about where the price goes. What the number actually is: point C plus 1.618 times the distance from A to B. Whether the price gets there is not something proportion arithmetic on three past prices can address, and nothing on this page suggests it will.

Last reviewed 29 August 2026. See our methodology and editorial policy.

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