Sin, Cos and Tan Calculator
Enter an angle to get its sine, cosine or tangent in degrees or radians; for example sin(30°) = 0.5, cos(60°) = 0.5 and tan(45°) = 1.
At a glance
| What it is | Free sin, cos and tan calculator in degrees or radians, with inverse trig. Includes the table of exact values for 0°, 30°, 45°, 60° and 90°. |
|---|---|
| Type | Interactive guide with a calculator |
| Level | High school and college |
| Price | Free, with no account or sign-up |
| Works offline | Yes, after the first visit; installs as an app |
| Made by | Aalok (aalok.builds@gmail.com) |
| Last updated | 1 November 2026 |
Key facts
| sin 0°, 30°, 45°, 60°, 90° | 0, 1/2, √2/2, √3/2, 1 |
|---|---|
| cos 0°, 30°, 45°, 60°, 90° | 1, √3/2, √2/2, 1/2, 0 |
| tan 0°, 30°, 45°, 60° | 0, √3/3, 1, √3 (tan 90° is undefined) |
| Degrees to radians | radians = degrees × π ÷ 180 |
| Pythagorean identity | sin²θ + cos²θ = 1 |
Degrees or radians?
Check the mode before calculating: sin(30) is 0.5 in degrees but about −0.988 in radians. The rad/deg key switches the mode, and this page starts in degrees.
How to use it in Plotline
- sin(30) in degrees is already entered; its answer shows next to the input.
- Tap rad/deg to switch angle units.
- Tap 2nd for inverse functions: sin⁻¹, cos⁻¹ and tan⁻¹.
Frequently asked questions
Why does my calculator say sin(30) = −0.988?
It is set to radians, so it is finding the sine of 30 radians rather than 30 degrees. Switch the angle mode to degrees and sin(30) gives 0.5. Plotline shows the current mode on the keypad.
Is it free?
Yes. The scientific calculator is free with no account and no sign-up, and every function is available: logs, roots, trigonometry, factorials, powers and constants. It installs as an app on a phone or computer and works offline.
Learn more
Related
- Sine graph – Graph y = sin(x) online.
- Cosine graph – Graph y = cos(x) online and compare it with sin(x).
- Tangent graph – Graph y = tan(x) online.
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Plotline is an independent project and is not affiliated with Desmos, Texas Instruments or Casio.