Engineering & Complex Number Calculator

This calculator extends ordinary scientific arithmetic to complex numbers, using the electrical-engineering convention of a trailing j for the imaginary unit instead of i (since i is already used for current). Enter a complex number as 3+4j, or in polar form as magnitude∠angle — for example 5∠30 — and every operator (+, -, ×, ÷, ^) works on complex values exactly the way it works on ordinary real numbers, since a real number is just a complex number with a zero imaginary part.

A REC/POL toggle switches the result display between rectangular (a+bj) and polar (r∠θ) form, and the angle in polar results follows whichever DEG/RAD mode is currently set. An ENG toggle switches numeric display to engineering notation — the exponent is rounded to the nearest multiple of 3 and shown with its SI prefix (p, n, µ, m, k, M, G, T), the same convention used on multimeters and datasheets, instead of raw scientific notation.

Trigonometry, logarithms, and square root operate on real numbers only, exactly as in the Scientific calculator — applying one of them to a value with a non-zero imaginary part returns an error rather than a silently wrong answer, since general complex analytic functions are outside this calculator's scope. Every result is added to a scrollable History tab (stored in your browser only), so you can tap back into an earlier result instead of retyping it.

1. Build an expression using digits, operators, and the j key for imaginary numbers (e.g. 3+4j) or the ∠ key for polar entry (e.g. 5∠30), then press =.
2. Use REC/POL to switch how the result is displayed, and ENG to switch between standard and SI-prefixed engineering notation.
3. Check the History tab to see or recall previous results — tap any entry to bring it back into the current expression.