You should be fine. The wattage calculator usually tells you power you will use and the 700w on your PSU is max power. Normally a descent power supply will be "Certified" and tell you a percent like 80%. You take the max rated output 700w and multiply it by the percent 700 x .80 = 560. So a 700watt PSU rated at 80% is guaranteed to generate a continuous 560 watts. While you are close to this number, as long as you have a descent quality PSU you should be just fine.