Many software companies use thermometers to show progress toward an event's fundraising goal. Swell doesn't use them.
They were originally part of the software, but the reality is, they simply don't work as well as you'd think. In fact, we've repeatedly seen organizations raise far more without a thermometer than with one.
If your heart is absolutely set on including a goal, consider including it in the text on your personal fundraising pages (setup--> details) or on your home page (setup--> content). If you really need to have a graphic representation you can create a graphic like the one attached here in Canva or your favorite graphics program to include on your home page. Bonus: either of these methods lets you easily change your mind about how much you want to raise.