The PROFITS Center calculators work "in the browser."
Your entries – and therefore the calculations for you – will be retained in the browser you use for input (e.g., Firefox, Chrome, Safari, Edge), subject to your settings for clearing its history.
No more worries if you are interrupted while working with it. When you resume, just use the same browser and device, and your plans will be there! (Even if it is a few days later, so long as you have not cleared the history in that browser.)
Time to update your plans?
Whenever you return, using the same device and browser, you should find each of your plans on its own page, ready for you to update your inputs.