Set the high to 150.00, the low to 100.00 and the trend to bullish, and the Fibonacci retracement calculator returns seven retracement levels stepping down from 150.00 to 100.00, the 130.90 level at 38.2 percent, and three extensions above the high, the 180.90 target at 161.8 percent being the farthest practical one. Every price is computed locally in the browser, and nothing is uploaded.
0 percent and 100 percent are the swing itself
The 0 percent row is the 150.00 high and the 100 percent row is the 100.00 low, so the table is anchored by the swing you entered, not by anything external. In a bullish trend the current price is the high, and the distance column reads as negative numbers: the 138.20 level at 23.6 percent sits 11.80 below 150.00, and the 130.90 level at 38.2 percent sits 19.10 below it. That distance view is what makes the table actionable. The stop loss / take profit calculator takes the same high and low and turns selected levels into concrete stop and target lines, so a 38.2 percent retest becomes a number on the order form rather than a line on a chart.
Why 38.2 and 61.8: the golden ratio
The two levels traders lean on most come from the golden ratio. With phi at 1.618, one over phi is 0.618, and one minus 0.618 is 0.382, so the 38.2 percent and 61.8 percent levels are the same ratio measured from opposite ends of the swing. Their product, 0.618 times 0.382, gives 0.236, which is where the 23.6 percent level comes from, and 78.6 percent is its deeper mirror. The 50 percent level is not a Fibonacci number at all; it is the psychological midpoint, included because it is where most people look. The Bollinger Bands calculator measures the same question, how wide a price move is, with a rolling volatility envelope instead of one fixed swing, which is why the two tools often flag overlapping zones.
Retracements stay inside the range, extensions leave it
All seven retracement prices live between 100.00 and 150.00, because a retracement by definition gives back part of the move. The three extensions do not: 127.2 percent sits 13.60 above the high at 163.60, 161.8 percent sits 30.90 above at 180.90, and 261.8 percent sits 80.90 above at 230.90. The 261.8 level is 100 plus 161.8, a full range added to the 161.8 extension, which is why it shows up as the far target in momentum scenarios. The drawdown calculator works on the mirror idea, measuring how far a price falls back from a high, so the distance from 180.90 back down to 150.00 is the same arithmetic as the 230.90 extension seen upside down.
Bullish and bearish are mirrors
Keep the 150.00 high and the 100.00 low but flip the trend to bearish and the whole table inverts: the current price becomes 100.00, the 23.6 percent level climbs to 111.80, and the 61.8 percent level climbs to 130.90. The mirror is exact: the bullish 38.2 percent price of 130.90 is the bearish 61.8 percent price, and the bullish 23.6 percent price of 138.20 is the bearish 78.6 percent price, so one pair of inputs prices both directions of the trade. The ATR calculator sizes the same swing with recent volatility instead of a fixed pair of prices, a useful cross check on whether the 50.00 range is unusually wide or narrow for this instrument.
Turning the levels into a risk plan
The geometry does the risk math for you. Enter long at the 38.2 percent retest of 130.90, stop below the full retrace at 100.00, and target the 161.8 percent extension at 180.90, and the risk is 30.90 while the reward is 50.00, a 1.618 to 1 ratio that is the golden ratio again. If the trade reaches the 261.8 percent extension instead, the reward doubles to 100.00. The risk reward guide walks through how to set that stop and target deliberately, because the levels only work as a plan when the exit is fixed before the entry.
From the levels to a decision
The calculator marks candidate prices, it does not confirm them. A 38.2 percent level is worth watching when it lands near a previous high, a round number, or a cluster of volume, and it is noise when it does not. The backtest performance metrics tool is the honest way to check a rule like buying the 38.2 percent retest, turning a chart pattern into win rate and payoff statistics instead of a memory. Once a rule survives that check, the position sizing tool sizes the trade so that a stop at 100.00 costs the planned fraction of the account, which is where the levels stop being geometry and start being a plan.