The Rental Wire / Planning tools
Rental Property CapEx Calculator
Estimate what to save for major replacements, also called capital expenditures or CapEx. Use the cost, time remaining and savings for each item.
What comes due first?
Check when each replacement is due. Work due now needs cash now, in addition to the monthly savings shown above.
| Component | Due in | Still to save |
|---|---|---|
| Enable JavaScript to see the full replacement schedule. | ||
How the reserve calculation works
Future replacement cost = today’s cost × (1 + annual cost increase)years remaining
Monthly contribution = max(0, future cost − savings assigned to this item) ÷ months remaining
For work due now, the remaining cost goes into the immediate-funding total. For future work, contributions start today and stop at that item’s first replacement date. The 12-month total stops contributions for items due sooner than a year.
A worked example
A roof estimated at $12,000 today, due in eight years, reaches about $15,201 at 3% annual cost growth. With $2,000 already reserved for that roof, the remaining $13,201 requires about $137.51 a month over 96 months. A roof due today needs its unfunded cost in cash now.
These figures are planning examples, not price benchmarks or useful-life recommendations. A local quote and an inspection of the actual component will give you better inputs than the age of the house alone.
Questions about replacement reserves
Is CapEx the same as routine maintenance?
This planning tool separates major replacements from recurring repairs and upkeep. A roof replacement can go here; small ongoing repairs belong in a separate maintenance budget. Tax treatment is a different question and is not determined by this calculator.
Should I enter total lifespan or remaining life?
Remaining life from today. A roof that you expect to replace in three years should use 3, even if its original expected life was much longer. Do not infer replacement timing from the building’s age if the equipment has been changed.
How do I use one pooled reserve account?
Assign its current balance across the components once. Do not enter the full account balance on every row. Excess savings on one item do not automatically cover another; move the allocation yourself if that is your plan.
Why might the monthly amount look high?
A replacement due soon leaves fewer months to save. The monthly amount fills the gap between your current savings and the next replacement cost. Review that gap before buying.
Does this fund replacements forever?
No. It funds the next replacement for each component you list. It does not model repeated replacement cycles, investment returns or unexpected failures. After a replacement, enter the new expected remaining life and update the savings assigned to that item.
Can I use this for a duplex or small portfolio?
Yes. Include each major component and its full replacement cost, or group similar items if they are due together. Avoid adding both a whole-property allowance and the same itemized replacements. The tool supports up to 20 rows.