Example 1
- 45°
1.000000
What is cot(45°)? School writes 1. The calculator keeps six zeros after the one.
Cotangent
Type an angle in degrees. Cotangent is 1/tangent, adjacent over opposite. cot(45°) comes out 1.000000. cot(30°) ≈ 1.73205. cot(60°) ≈ 0.57735.
The angle is in degrees. The calculator computes 1/tan after × π/180. At 0° the result is Infinity, because tangent is zero.
Results
Enter data and click Calculate.
How it works
The cotangent of an acute angle in a right triangle is the adjacent leg divided by the opposite one. That is 1/tangent. At 45° the legs are equal, so school writes cot(45°) = 1. The calculator computes 1/tan and at 45° shows 1.000000, leftover from π in six decimals.
Degrees do not go into tangent on their own. First the angle times π/180. 30° is π/6 and cot(30°) ≈ 1.732051, which is √3. 60° is 1/√3 ≈ 0.577350. Same triangle, swapped legs versus tangent.
The field is the angle in degrees. A comma and a dot are the same decimal. A negative angle passes: cot(−45°) is the minus of the same size. 180° behaves like 0°, again a divide by almost zero.
At 0° school cotangent does not exist. Here you get the word Infinity, not a blank. At 90° tangent is huge and cotangent falls almost to zero.
Tangent of the same angle is on the neighbouring page. Sine and cosine take another ratio. Degrees to radians also live next door, with no cotangent in the box.
cot(45°) = 1.000000. cot(30°) ≈ 1.73205. cot(60°) ≈ 0.57735. At 1° the number is already large, because you are near the vertical wall of tangent at zero.
Formula
cot(α) = 1 / Math.tan(α° × π / 180)
How to use
- Type the angle in degrees, for example 45.
- Click Calculate. cot(45°) comes out 1.000000.
- 30° gives about 1.73205. 60° gives about 0.57735.
- 0° prints Infinity, because you divide by tan(0°) = 0.
- Tangent of the same angle lives on the neighbouring card.
cot(45°) = 1.000000
Cotangent is 1/tangent. The calculator uses degrees. cot(45°) = 1.000000. cot(30°) ≈ 1.73205. 0° prints Infinity.
- cotangent
- Adjacent over opposite. School cot(45°) is 1. Here you see 1.000000.
- degrees
- The calculator input. 30° gives ≈ 1.73205. 60° gives ≈ 0.57735. The field is not radians.
- tangent
- The reciprocal of cotangent. At 0° it is zero, so you get Infinity instead of a blank.
Examples
Example 2
- 30°
1.732051
What is cot(30°)? About 1.73205, which is √3.
Example 3
- 60°
0.577350
What is cot(60°)? About 0.57735, which is 1/√3.
Related calculators
Common questions
What is cot(45°)?
In a notebook, 1. The result is 1.000000, because 1/tan(45°) is not a clean one in machine float.
What does cotangent mean?
Adjacent over opposite, or 1/tangent. At 45° the two legs are equal.
What are cot(30°) and cot(60°)?
cot(30°) ≈ 1.73205, which is √3. cot(60°) ≈ 0.57735, which is 1/√3.
Does the calculator take degrees or radians?
Degrees. The calculator converts degrees to radians by multiplying by π/180. Typed 45 means 45°, not 45 radians.
What happens at 0°?
In school, cotangent does not exist. Here you get Infinity, because tan(0°) = 0.
What happens at 90°?
Almost zero. Tangent at 90° is huge, so 1/tan falls to a fraction.
Does a negative angle work?
Yes. cot(−45°) is negative and the same size as cot(45°).
How is cotangent different from tangent?
They are inverses. cot(30°) is 1/tan(30°). Same angle, flipped ratio.
Why is π in the conversion?
The tangent function uses radians. A degree is 1/180 of π. That is why α × π/180.
Does a comma in 45.5 work?
Yes. 45.5 and 45,5 are the same angle.
Knowledge sources
The calculator computes the same formula as the definition below.
Page updated in 2026.