Powers of i Calculator

Evaluate any positive, zero, or negative integer power of the imaginary unit using its repeating four-value cycle.

Calculate an integer power of i
Enter an integer exponent to reduce it modulo four and find the exact result.

About powers of the imaginary unit

The imaginary unit i is defined by the equation i² = -1. That single definition extends the real number system into the complex numbers and creates a remarkably simple pattern for integer powers. Starting at exponent zero, the values are 1, i, -1, and -i. Multiplying once more by i returns to 1, so the same four results repeat forever. This calculator finds the correct point in that cycle without carrying out a long chain of multiplication. To evaluate i raised to an integer n, divide n by four and use the remainder. A remainder of zero gives 1, a remainder of one gives i, a remainder of two gives -1, and a remainder of three gives -i. For example, 27 leaves remainder three when divided by four, so i²⁷ equals -i. The quotient does not matter because every complete group of four contributes i⁴, which equals 1 and therefore does not change the product. Negative exponents follow the same cycle. By the reciprocal rule, i to the power -1 equals 1 divided by i, which simplifies to -i. A mathematically normalized modulo operation maps every negative integer to a remainder from zero through three. Thus -6 maps to remainder two and i raised to -6 equals -1. The calculator performs that normalization automatically, avoiding the negative-remainder behavior found in some programming languages. Powers of i appear when simplifying complex-number expressions, solving polynomial equations, studying electrical circuits, and working with waves or rotations. Euler's formula connects complex exponentials to sine and cosine, while multiplication by i corresponds geometrically to a counterclockwise quarter-turn in the complex plane. Four multiplications produce a full rotation, which gives an intuitive explanation for the four-step cycle. Only integer exponents use this unique single-valued cycle. Fractional and general complex powers require roots and logarithms, which can have multiple branches, so they are outside this calculator's scope. Enter zero, a positive integer, or a negative integer. The displayed remainder shows exactly why the result was selected and gives a quick method you can reproduce by hand on an exam. When simplifying a larger expression, reduce each power separately and then combine ordinary coefficients and like terms. For instance, i¹¹ plus i¹⁴ becomes -i plus -1. Keeping the four-value table nearby is often enough for small exponents, but modular reduction is faster and less error-prone when exponents are large or negative.

Powers of i examples

Each exponent reduces to one of four values according to its remainder modulo four.

PowerValueReason
i⁰1Zero has remainder zero.
i⁷-iSeven has remainder three.
i¹⁸-1Eighteen has remainder two.
i⁻⁹-iNegative nine normalizes to remainder three.

How to use the powers of i calculator

  1. Enter the positive, zero, or negative integer used as the exponent.
  2. Choose Calculate Power to divide the exponent by four conceptually.
  3. Read the normalized remainder and the corresponding exact value.
  4. Substitute the result into your larger complex-number expression.

Powers of i calculator FAQ

Why do powers of i repeat every four?

Because i² equals -1 and i⁴ therefore equals 1. Multiplying by another group of i⁴ leaves any existing value unchanged.

What is i to the power zero?

It equals 1 under the standard zero-exponent rule for nonzero bases. This value also begins the repeating four-step cycle.

Can the exponent be negative?

Yes, negative integer powers are reciprocals of positive powers. Normalizing the exponent modulo four places them in the same cycle.

What is the square root of i?

That uses a fractional exponent rather than an integer power and has two square-root values. This calculator intentionally handles only the unambiguous integer-power cycle.

How does modulo four find the answer?

Every four factors of i multiply to 1 and can be removed. The remainder counts the factors still needed after all complete groups are discarded.