App for FIRE movement?

Since there are lots of fans of FIRE movement and it seems that people need to calculate and track their expenses and savings, there could be an app that uses the 50/30/20 rule and helps you track your expenses, calculates your savings rate and FIRE date. <br><br>You could calculate your expenses, divide them into 50%, 30% and 20% categories, add your income and expenses, add some info about your current savings. You could track your progress and check how much and what expenses you had. The app could also calculate your FIRE day and how long it will take. <br><br>Idea is pretty simple, and you could add FIRE calculator and expenses tracker into one app. It would be nice if it had a clean UI and was easy to use. Think that it could be useful for FIRE movement activists and people who want to save money and time.