How do I turn my monthly expenses into a FIRE target quickly?

Use a simple three-step shortcut. First, add up your true monthly spending, including annual bills like insurance and property taxes averaged into a monthly figure. Second, multiply by 12 to get annual expenses. Third, multiply by 25 for a 4% rate, or by about 28 to 30 for a more conservative early-retirement rate.

Example: $5,000 a month is $60,000 a year, which is $1.5 million at 25x or roughly $1.8 million at 30x. Remember to use your expected retirement spending, not your current spending, since costs like commuting may fall while healthcare and travel may rise. This back-of-the-envelope number is a starting point; refine it with inflation and return assumptions using wealthserene.com/tools/fire-calculator.