Sine Cosine Tangent Calculator
Find the sine, cosine and tangent of an angle — plus cosec, sec, cot and the angle in radians.
Enter Values
How to use this calculator
- Enter the angle (decimal degrees, or switch the field to DMS/DDM).
- Read sin, cos and tan, plus the reciprocal ratios and the angle in radians.
How it works
The calculator converts the angle to radians (radians = degrees × π ÷ 180) and evaluates the three primary trigonometric ratios: sine, cosine and tangent.
It also returns the reciprocals — cosec = 1 ÷ sin, sec = 1 ÷ cos and cot = cos ÷ sin. A ratio is shown as undefined where its denominator is zero (tan and sec at 90°, 270°…; cosec and cot at 0°, 180°…).
Worked example
Angle = 30°. sin 30° = 0.5, cos 30° ≈ 0.866025, tan 30° ≈ 0.577350; in radians, 30° ≈ 0.523599.
Common mistakes
- Working in radians when the field expects degrees (or vice versa) — this tool takes degrees and shows the radian value separately.
- Expecting a value for tan 90°: it is undefined because cos 90° = 0.
Frequently asked questions
How do you calculate sin, cos and tan of an angle?
Convert the angle to radians (radians = degrees × π ÷ 180), then take sin, cos and tan of that value. For 30°: sin = 0.5, cos ≈ 0.866 and tan ≈ 0.577.
Why is tan 90° undefined?
tan = sin ÷ cos, and cos 90° = 0. Dividing by zero is undefined, so tan is undefined at 90°, 270° and every 180° from there.
What are cosec, sec and cot?
They are the reciprocals: cosec = 1 ÷ sin, sec = 1 ÷ cos and cot = cos ÷ sin (= 1 ÷ tan). Each is undefined wherever its denominator is zero.
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