Not sure where to start

Which calculator does your question need?

Most of the time the answer comes down to one thing: do you need a number, or do you need a picture?

If your question ends in a single value, such as a sine, a logarithm or how many committees you can form from ten people, reach for the online scientific calculator. If your question is about shape, such as where a curve crosses the axis or where two lines meet, you want the free online graphing calculator and its step by step guide.

Polar is the odd one out, and the choice there is made by the geometry rather than by you. Anything built around a centre, such as a radar sweep, a spiral shell or a planetary orbit, is far simpler in r and θ than in x and y. When that is your situation, the polar graphing calculator and the guide to graphing polar equations are the right starting point.

Choosing between the three calculators
You want toUseGuide
Evaluate a trig value, log or factorialScientificOn the tool page
Plot a function and find its rootsGraphingGraphing guide
Find where two curves intersectGraphingGraphing guide
Shade an inequality or draw a circleGraphingGraphing guide
Draw a cardioid, rose curve or spiralPolarPolar guide
Convert between polar and rectangularPolarPolar guide
Three symbols side by side representing a scientific calculator, a Cartesian grid and a polar grid
A number, a curve, or a shape built around a centre. That choice picks your tool.

Reading is good. Trying is better.

Every guide is written next to a tool you can open in the same breath. Nothing to install, nothing to sign up for, no limits on what you can plot.