Steps
Use a fixed order: accounts, contributions, years, fee percent, tax wrapper. Skip a line and two strategies stop being comparable.
For time and savings, Time vs Money is the conceptual map; your spreadsheet is the checklist.
Checks
If totals disagree between you and a counterparty, do not recalculate until you both show line items side by side.
Still stuck? Re-read Related lesson with your numbers in hand, not the example numbers on this page.
Check your numbers now
Worked mini example
Procedure pass: starting balance, $400 monthly, 7% return, 0.25% fee, 25 years, contributions at month start. Anything missing?
Two tempos
| Skipped step | Where time and savings breaks |
|---|---|
| Jump to headline price or ticker | Miss expenses, fees, or timing on time vs money |
| One-shot math | No sensitivity to rate, rent, or return |
| Trust a screenshot | Stale assumptions versus today’s quote |
Time vs Money: slow checklist, then tool Fast tool, then verify lines
Sensitivity pass
Core lesson
Related: Time vs Money. To test sensitivity, change one input at a time in the calculator.
Use the calculator
FAQ
- Where is the main lesson?
Time vs Money is the hub with related lessons linked from it.
- Which calculator should I open first?
Use Investment growth or Lump sum growth for long horizons; Savings goal for targets; Debt payoff when comparing to loans.