How do I switch my TI-84 from radians to degrees?

Press MODE, arrow to DEGREE, press ENTER to select it, then press 2nd + MODE (QUIT). Test with sin(30) — you should get 0.5.

How do I know if my TI-84 is in degree or radian mode?

Press MODE and look at the third row — the highlighted option is active. Or type sin(30): 0.5 means degrees, -0.988 means radians.

Should I use degree or radian mode?

Use degrees for geometry and most high-school trig. Use radians for pre-calculus, calculus, and physics — anywhere you see π in angle measures.

Why are my trig answers wrong on my TI-84?

Nine times out of ten, the mode is wrong. If your class works in degrees but the calculator is in radians (or vice versa), every sin, cos, and tan answer comes out wrong. Check MODE first.

Does degree/radian mode affect anything besides trig?

Mainly the trig functions (sin, cos, tan and their inverses). Regular arithmetic, exponents, and logs are unaffected by the mode setting.

How do I switch modes on the online emulator?

Tap the DEG/RAD button above the keypad on our free TI-84 emulator. It toggles instantly, and the current mode is always visible so you never have to guess.

TI-84 Degree vs Radian Mode

The #1 cause of mysterious wrong answers. Fixed in 30 seconds.

Your trig answers are perfect, your steps are right — but every answer is wrong. Before you panic, check one setting. This page explains the degree/radian trap and how to escape it.

How to switch modes

1Press MODE
On a real TI-84, press the MODE key (top row). You will see a settings screen with options like RADIAN and DEGREE on the third row.
2Highlight DEGREE or RADIAN
Use the arrow keys to move the cursor onto DEGREE or RADIAN, then press ENTER to select it. The selected option shows in highlighted text.
3Press 2nd + MODE to quit
Press 2nd + MODE (QUIT) to return to the home screen. Your choice is saved — it stays until you change it again, even after turning the calculator off.
4Test it: sin(30)
Type sin(30) and press ENTER. In DEGREE mode you get 0.5. In RADIAN mode you get -0.988 — a totally different number. This instant check tells you which mode you are in.

When to use which mode

Degrees are the everyday unit — 90° is a right angle, 180° is a straight line. Geometry class and most high-school trig live in degrees. If your problems say things like sin(30°), you want DEGREE mode.

Radians are the mathematician's unit — π radians is a half circle, 2π is a full one. Pre-calculus, calculus, and physics switch to radians because the formulas get cleaner. If you see π inside angle measures, you want RADIAN mode.

The classic trap

Here is how it happens. You finish geometry in DEGREE mode. Next semester, pre-calculus starts and everything is in radians — but nobody tells your calculator. Suddenly sin(π/6) gives a nonsense answer, and you redo the problem three times before suspecting the tool instead of yourself.

Build one habit and you will never fall for it: whenever trig answers look wrong, check the mode first. Type sin(30). If you expected 0.5 and got −0.988, you found the culprit in five seconds.

Practice without the risk

Our free TI-84 emulator has a one-tap DEG/RAD toggle with the current mode always visible — no MODE-menu hunting. Try sin(30) in both modes and watch the answer change. That five-second experiment teaches the lesson better than any paragraph.

Working through trig graphs too? Our graphing guide shows how to plot sin(x) and cos(x) step by step.

Frequently asked questions

Last updated: September 26, 2026