After two time constants, the capacitor in an RC circuit is charged to what percentage of the supply voltage?

The charging of a capacitor in an RC circuit follows an exponential curve where each successive time constant adds 63.2% of the remaining uncharged voltage difference. After the first time constant, the capacitor reaches 63.2% of the supply voltage. The remaining uncharged portion is 36.8%. During the second time constant, the capacitor charges an additional 63.2% of that remaining 36.8%, which equals roughly 23.3%. Adding the 63.2% from the first time constant and the 23.3% from the second gives approximately 86.5% of the total supply voltage. The distractor 63.2% represents only one time constant, 36.8% is the discharging value, and 95% represents approximately three time constants.