An exponent says how many times to multiply the base by itself: 210 = 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 1,024. A negative exponent means the reciprocal: 2-3 = 1 / 23 = 0.125. A fractional exponent is a root: 90.5 is the square root of 9 = 3, and 271/3 is the cube root of 27 = 3.
It equals 1 (for a base other than 0). 50 = 1 and (-7)0 = 1.
(-8)1/3 has a real answer (-2) but (-8)0.5 would be imaginary, and (-8)0.3333 is not defined among real numbers. The calculator shows a dash when the result is not real.
Results beyond about 1.8 x 10308 overflow in a browser and show as too large.
See also: square root calculator · logarithm calculator · scientific notation converter