Tangent Calculator – Calculate tan(x)

Find the tangent of an angle using the tan calculator below. Start by entering the angle in degrees or radians.

How to Find the Tangent of an Angle

In a right triangle, the tangent of angle α, or tan(α), is the ratio between the angle’s adjacent side and the opposite side.

illustration of a triangle showing the formula for tangent being equal to side a divided by side b

Tangent is one of the three primary trigonometric functions and is abbreviated tan.

You might be asking how to find the tangent of an angle? Use the formula below to calculate tan.

Tangent Formula

The tangent formula is:

tan(α) = opposite aadjacent b

Thus, the tangent of angle α in a right triangle is equal to the opposite side’s length divided by the adjacent side’s length.

To solve tan, simply enter the length of the opposite and adjacent and solve.

For example, let’s calculate the tangent of angle α in a triangle with the length of the opposite side equal to 4 and the adjacent equal to 8.

tan(α) = 48
tan(α) = 12

Tangent Graph

If you graph the tangent function for every possible angle, it forms multiple curves from lower values to higher that never touch the angles at 90° or 270° increments.

illustration showing the curves representing possible tangent values

Tangent Table

The table below shows common angles and the tan value for each of them.

Table showing common angles and tangent values for each.
Angle (degrees) Angle (radians) Tangent
0 0
30° π6 1√3 = √33
45° π4 1
60° π3 √3
90° π2 undefined
120° 3 -√3
135° 4 -1
150° 6 1√3 = –√33
180° π 0
210° 6 1√3 = √33
225° 4 1
240° 3 √3
270° 2 undefined
300° 3 -√3
315° 4 -1
330° 11π6 1√3 = –√33
360° 0

Inverse Tangent and Cotangent

The inverse of the tangent function is the arctan function. Thus, if you know the tan of an angle, you can use arctan to find the angle.

Cotangent, on the other hand, is the reciprocal of the tangent value. The following formulas show the relationship between tangent and cotangent.

tan(α) = oppositeadjacent
cot(α) = adjacentopposite = 1tan(α)

You might also be interested in our sine and cosine calculators.