In an effort to calm volatile markets, the stock exchanges implemented Limit Up Limit Down (LULD), a mechanism to prevent stocks from trading above or below calculated price boundaries, also known as price bands.
LuldCalc is a calculator for traders and stock exchange operators, and is handy for identifying these bands. It has buttons for tier 1 and tier 2 stocks, and calculates double-wide bands for market open and market close. It's a basic calculator too.
So put away your business calculator and memory functions. Set aside that pencil and paper. Don't bother loading a spreadsheet to calculate a stock's price bands. Use LuldCalc.