The Sun emits 3.8 x 10^33 ergs/sec or 3.8 x 10^26 watts of power...or each second, an amount of energy equal to 3.8 x 10^26 joules.

In one hour, or 3600 seconds, it produces 1.4 x 10^31 Joules of energy or 3.8 x 10^23 kilowatt-hours.

Since E = mc^2, in 1 hour it looses (1.37 x 10^37 ergs)/(9 x 10^20) = 1.5 x 10^16 grams or 1.5 x 10^10 metric tons of mass.

It's been doing this for about 4.5 billion years!