How to use the Fibonacci Calculator?

The Fibonacci Calculator helps the trader calculate the Fibonacci retracements and extensions based on extreme points on the chart.   

If, for example, you want to calculate the Fibo points of an uptrend on the EUR/USD between 1.0800 and 1.1000, enter these rates in the Low and High fields to get the possible retracements according to Fibonacci. The custom field affects only the “Extensions” calculation.  

If the chart already shows a complete retracement move (let’s say the market went up from 1.0800 to 1.1000 and then retraced from 1.1000 to 1.0850 and started moving up again), you can enter the ‘turning point’ rate (1.0850) in the “Custom” field to see potential extension rates (i.e., where the market may extend its uptrend move.) For example, according to Fibonacci Extension, a 200% extension will reach 1.1250.     

The same thing applies for downtrend moves (e.g., if the market moved from 1.1000 to 1.0800).  

See example below.  

https://www.investing.com/tools/fibonacci-calculator