You don’t need to calculate it mathematically, you may do that but it is more or less a waste of time. Since, we can’t predict the market. No matter how good is your mathematical approach to calculate momentum of a stock, you will always fail to c A stock experiencing a 1% price movement from $300 to $303 would have a momentum value of three. A second stock experiencing a 100% increase in price from $3 to $6 also has a momentum value of three. Rate of Change Formula. One of the ways technical stock analysts can work around this problem is by calculating a rate of change value, which normalizes momentum: RoC = (CP - CP n) / CP n. Where: RoC = Rate of Change; CP = Closing price in the current period Price momentum surges, especially if accompanied by volume surges often presage a significant move. Stocks in a database of about 8,000 stocks are ranked by momentum. Momentum is similar to price-rate-of-change. The difference is that momentum is expressed usually as a ratio, and price-rate-of-change is expressed as a percent.