Tangent tells you the slope for an angle; arctangent runs the other direction, handing you the angle for a slope. If tan(θ) = opposite/adjacent, then θ = arctan(opposite/adjacent) — and that inversion is quietly one of the most-used calculations in applied math. A wheelchair ramp rising 1 foot over 12 feet of run has a slope of 1/12, and arctan(1/12) reveals its angle: about 4.76°. Surveyors, navigators, carpenters cutting rafters, and game developers aiming projectiles all reach for arctan when they know the rise and run but need the angle. One practical note: calculators return the principal value between -90° and 90°, so if your x-component is negative you may need to add 180° to land in the correct quadrant — programmers know this as the reason the atan2 function exists. This calculator evaluates the inverse tangent for you: enter your values in the Variable A and Variable B fields and read the Result, then sanity-check that a small ratio gives a small angle.

With the pre-filled defaults — Variable A 10, Variable B 5 — the Arctan Calculator returns Result 50.0000. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.