Power Calculation on a Calculator: A Step-by-Step Guide

Power calculation on a calculator means raising a number to an exponent, such as calculating 2 to the 3rd power. Enter a base and an exponent to get the result; the steps below cover scientific calculators and basic calculator workarounds.

What You’ll Need

A calculator with a power key, often marked xʸ, yˣ, or ^. A scientific calculator app or web calculator also works.
The base and exponent in your calculation. For example, in 5³, 5 is the base and 3 is the exponent.

Step-by-Step

Identify the base and exponent. In an expression such as 4³, the base is 4 and the exponent is 3. The exponent tells you how many times to use the base as a factor: 4³ = 4 × 4 × 4 = 64.
Find the power key. Look for xʸ, yˣ, ^, or a similar key. On some calculators, the key may be labeled EXP, but that often means scientific notation rather than raising a number to a power. Check the key’s label and your calculator’s instructions if uncertain.
Enter the base. Type the number that is being raised to a power. For example, for 5³, enter 5.
Press the power key. Tap xʸ, ^, or the equivalent. Some calculator layouts require you to press the power key before entering the base; if the next step does not work as expected, try that order or consult the manual.
Enter the exponent. Type the smaller raised number. For 5³, enter 3.
Calculate the result. Press = or Enter if your calculator does not evaluate automatically. For 5³, the display should show 125.
Check the expression and result. Confirm that the base and exponent were entered in the intended order. For a positive whole-number exponent, multiply the base by itself that many times to check the answer.
Use parentheses for a negative base or a longer expression. To calculate (−2)⁴, enter the negative base inside parentheses if the calculator supports them. This gives 16. Without parentheses, −2⁴ is conventionally interpreted as −(2⁴), which equals −16.

Common Mistakes

Reversing the base and exponent: 2³ is 8, but 3² is 9. Check the order shown on the display before calculating.
Confusing a power key with scientific notation: An EXP or EE key commonly enters a number multiplied by a power of 10. For example, 3 EXP 4 can mean 3 × 10⁴, not 3 to the 4th power. Use the dedicated power key for ordinary exponentiation.
Leaving out parentheses: Negative signs and multi-part bases can change the result. Use parentheses when the entire negative number or expression is the base.
Assuming a negative exponent makes a negative answer: A negative exponent means take the reciprocal. For example, 2⁻³ = 1 ÷ 2³ = 1/8.
Rounding too early: Keep the calculator’s full displayed precision for intermediate steps, then round the final answer to the precision you need.

Tips

For a square, use the dedicated x² key if available. For a cube, use x³ if available. Otherwise, use the general power key.
For a square root, many calculators have a √ key. A square root is also a power of one-half: √9 = 9^1/2 = 3.
For a reciprocal, use the 1/x key if available, or calculate the number to the power of −1. For example, 5⁻¹ = 1/5 = 0.2.
When using an expression such as (2 + 3)², calculate the entire parenthesized base. Parentheses make the intended order clear.
For large powers, use scientific notation if the calculator displays it. A result such as 1.2E6 means 1.2 × 10⁶, or 1,200,000.

Troubleshooting

The calculator shows an unexpected answer: Check whether you entered the base first, followed by the power key and exponent. Try the alternative key order if your model uses a different entry system. Confirm that no old value or operation remains on the display; clear the calculation and start again.
You see an error or an undefined result: A zero base with a negative exponent requires division by zero, which is undefined. Some other inputs, such as a negative base raised to a non-integer exponent, do not produce a real-number result on ordinary calculators. Check that your inputs are appropriate for the calculation.
The result looks too large or too small: Check for a misplaced decimal point, an incorrect exponent, or a scientific-notation key used instead of the power key. Read any E or ×10 display as scientific notation, not as an ordinary digit in the answer.
You cannot find xʸ: Look for a secondary function printed above or below another key. A Shift, 2nd, or Fn key may reveal it. If the calculator has no power function, use repeated multiplication for positive whole-number exponents, or use a calculator app with a scientific layout.
Negative-base results differ between calculators: Enter the negative number with parentheses, such as (−2)^3. Some calculators apply the minus sign after exponentiation unless the base is grouped explicitly.

Frequently Asked Questions

What does “to the power of” mean?

It means multiplying a base by itself according to the exponent. For example, 3⁴ = 3 × 3 × 3 × 3 = 81.

How do I calculate a number squared?

Enter the number and press x², or enter the number, press the general power key, enter 2, and calculate. For example, 7² = 49.

How do I calculate a negative exponent?

Enter the base, use the power key, then enter the negative exponent with the calculator’s sign-change key. For example, 4⁻² = 1/4² = 1/16 = 0.0625.

What is zero raised to the zero power?

Many calculators display an error or treat 0⁰ as undefined. In some mathematical contexts it is assigned a value of 1, so follow the convention required by your class or application.

Can I raise a negative number to a fractional power?

Not always as a real number. For instance, (−8)^1/3 has the real result −2, but a general calculator may report an error or return a complex result. Check the calculator’s number mode and the mathematical convention being used.

Why does my calculator show E after a power calculation?

E usually indicates scientific notation. For example, 2.5E3 means 2.5 × 10³, or 2,500. It is a compact way to display a large or small result.

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.

More cards in this drawer

The whole Numbers and Powers drawer →