Problem: You don’t know your retirement number, so monthly investing feels random.
Promise: Get a clear target and turn it into a monthly plan you can actually follow.
If you want a money manager, not just another budget, see Money Manager for Sheets.
| Method | Best for | Trade‑off |
|---|---|---|
| Rule of 25 (4% rule) | Quick target | Not personalized |
| Expense‑first plan | Detailed budgeting | More setup time |
| Contribution‑backsolve | Monthly action plan | Requires assumptions |
The simple version
Estimate your annual spending in retirement, then multiply by a conservative factor (commonly 25× as a starting point). The point is not precision—it is turning “retire someday” into a target you can plan around.
For a step-by-step breakdown (including how to translate the number into monthly contributions), read: how much do I need to retire?
The plan that actually works
- Keep a cash buffer so you do not stop contributions every time life changes.
- Automate contributions on payday.
- Increase the contribution whenever income rises.
- Review quarterly, not daily.
Related reads: how much should I invest each month, monthly investing plan, and the finance answers hub.
Want your plan in one place? Open the free Google Sheet.