Oil price history charts display how much a barrel of crude oil cost during specific time periods using lines and graphs. Professional investors use financial websites that offer charts and graphs such as MacroTrends.com to compare oil prices from different time periods.
Oil traders base their investment decisions on a number of factors involving chart analysis. Professional investors use historic oil price charts and compare those prices to the U.S. Dollar Index looking for support and resistance levels, according to Forbes. Oil traders use support and resistance levels to keep prices from rising too high or falling too low, according to Investopedia.