Colorwheely creates color wheels from one or two hues of your choosing. There are a lot of apps, such as Adobe Color CC that will help you pick harmonizing colors based on a single anchor color. While ColorWheely can give create a color-wheel anchored from one color, it is particularly useful in scenarios where you've got two starter colors (such as a two-tone logo) you're trying to design around.
To select a hue to build the color wheel from, just click on a hue swatch.
This will open the hue picker dialog. Either click on the hue you want, or type an RGB color into the hex color input box. (Note: Cut-and-paste into the text input doesn't work due to security restrictions in the browser. Apologies!)
Close the hue dialog with the close (X) button.
The new hue should now be shown in the swatch. The numeric readout will always report the classical HSV hue in degrees. If you wish to stop using this hue, just click the close (X) button next to it.
You may choose to use an RYB (Red-Yellow-Blue) RGB or (Red-Green-Blue) color model. Different people have different preferences. Generally, RYB will provide a warmer color wheel than RGB. Feel free to experiment, and decide which one is best for you.
The Dissonance readout tells you how much the color wheel will have to be warped to accommodate all of your selected hues. This will be a number between 0° and 15°, inclusive. Ideally, you want to keep this number as low as possible. If you select only one color, this will always be 0°. Your color model selection may change the amount of dissonance reported, because the proximity of some hues varies between RYB and RGB.
Once you have the colors you want, you can optionally download an image of that wheel with the Export Wheel button.
If you would simply like to focus on a color harmony, you can select hues from the wheel by clicking on them. Click them again to deselect them.
The Export Selection button will export an image containing your selected hues in swatches with gradients spanning saturation and value. so that you can easily eyedropper them into a palette.