Fibonacci Retracements are ratios used to identify potential reversal levels. These ratios are found in the Fibonacci sequence. The most popular Fibonacci Retracements are 61.8% and 38.2%. Note that 38.2% is often rounded to 38% and 61.8 is rounded to 62%

Fibonacci Extensions: a retracement movement of a stock is where the stock "retraces" a section of one of its previous moves. In most cases, a stock performs a retracement at one of three standard Fibonacci levels: 38.2%, 50% and 61.8%. When a stock retraces more than 100% of its prior move, a Fibonacci extension can be calculated.