EnCalcGU calculates the cost of gas used, allowing both the real cost based on meter readings and forward prediction based on the readings and elapsed time. The results can be saved to log files for later analysis. The program can cope with different charging rates for gas at different times of the day, alternative rates based on a preset threshold, varying tax rates plus fixed charges and discounts enabling most charging models to be handled.Discounts can either be fixed amounts or a percentage of the cost. It also calculates the amount of CO2 generated. EnCalcGU is part of the JSutils group of software utilities which have a theme of energy conservation. Requires a registration code (free for personal non commercial use).