Excel POWER Function: Raise a Number to an Exponent
Raises a number to a power — the function form of the ^ operator.
POWER raises a number to an exponent: =POWER(2, 10) is 1024. The caret operator does exactly the same thing, so =2^10 is identical, and most people use the operator because it is shorter. POWER earns its place when the exponent is itself a formula and the caret would need bracketing to stay readable.
Its everyday use is compound growth. An amount growing at a rate r for n periods is amount * POWER(1 + r, n), which is the core of every savings projection and every inflation adjustment you will build.
It also does roots, because a root is a fractional power. The square root of a number is that number to the power of 0.5, and the cube root is to the power of 1/3. SQRT exists for the square case, but there is no CBRT, so POWER is how you get any other root.
Syntax
=POWER(number, power)Arguments
numberRequired- The base. Negative bases work with whole-number exponents but not fractional ones.
powerRequired- The exponent. Fractional values give roots; negative values give reciprocals.
The example data
Headers in row 1, data in A2:D6. C4 is blank and C6 holds text.
| A | B | C | D | |
|---|---|---|---|---|
| 1 | Sensor | Reading | Calibration | Batch |
| 2 | North inlet | 17 | 3 | 12 |
| 3 | South inlet | -4 | 5 | 7 |
| 4 | Header tank | 63 | 12 | |
| 5 | Overflow | 8 | 2 | 9 |
| 6 | Return line | -21 | n/a | 7 |
Worked examples
=POWER(B2, 2)Result: 289
17 squared. Identical to =B2^2.
=POWER(1.05, 10)Result: 1.6289
Compound growth: 5% a year for ten years multiplies the starting amount by about 1.63.
=POWER(B4, 1/3)Result: 3.9791
The cube root of 63, as a fractional exponent. There is no CBRT function, so this is the way.
=POWER(2, -3)Result: 0.125
A negative exponent gives the reciprocal: 1 divided by 2 cubed.
Now practise it
Reading about a formula is not the same as writing one. Open this function's exercise and type it into a real grid — you get instant feedback on exactly which cell is wrong and why.
Common errors and how to fix them
#NUM!
Why it happens: A negative base with a fractional exponent — the square root of a negative number has no real answer.
How to fix it: Take the root of the absolute value and reapply the sign if that is what you meant: =SIGN(A2)*POWER(ABS(A2), 1/3).
#VALUE!
Why it happens: One of the arguments is text.
How to fix it: Check both cells hold real numbers rather than numbers stored as text.
Result is not quite exact
Why it happens: Fractional exponents go through floating-point maths, so a cube root cubed may not return the original number precisely.
How to fix it: Round for display. This is a property of binary floating point, not an Excel bug.
Tips worth knowing
- ^ and POWER are interchangeable; use whichever reads better in the formula you are writing.
- SQRT(n) is clearer than POWER(n, 0.5) when you specifically want a square root.
- Compound growth over n periods is POWER(1 + rate, n) — the same expression that sits inside FV.
- To find the rate implied by a start and end value: =POWER(end/start, 1/years) - 1.
Frequently asked questions
What is the difference between POWER and the ^ operator?
Nothing functionally — =POWER(2,10) and =2^10 both return 1024. The operator is shorter for simple cases; the function is easier to read when the base or exponent is itself a long expression, because the arguments are separated by a comma rather than nested in brackets.
How do I calculate a cube root in Excel?
Raise the number to the power of one third: =POWER(A2, 1/3). There is no dedicated cube-root function. This works for any root — a fifth root is POWER(A2, 1/5).
Why does POWER return #NUM! on a negative number?
Because you asked for a fractional power of it, and negative numbers have no real fractional roots. Whole-number exponents work fine on negatives: =POWER(-4, 2) returns 16.
Related functions
Guides that use it
Longer reads where this function does real work in a real sheet.