Free calculator
CapEx reserve calculator
Turn your list of big-ticket replacements — roof, water heater, appliances — into one monthly set-aside. You supply the costs and timelines; the tool spreads them into a monthly number.
The short answer
Last updated: July 2026
A CapEx (capital expenditure) reserve is money set aside monthly for big-ticket replacements like roofs and water heaters. For each item, divide its replacement cost by the years until replacement, then by 12, and sum the results. A $12,000 roof due in 20 years adds $50 a month to the reserve.
After the estimate:
Tax season, already doneCapEx reserve calculator
Size a monthly reserve for big replacements.
List the big-ticket components you expect to replace, what each will cost, and how many years away it is. The tool spreads each cost over that timeline into one monthly set-aside.
Components (name + replacement cost + years away)
$
yrs
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yrs
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yrs
The starting rows are editable examples, not lifespan guidance — replace every name, cost, and timeline with your own numbers (a contractor quote or inspection report is the best source).
Input-driven result
Your inputs
Formula
Result below
Suggested monthly set-aside
$89.31
About $1,072 a year, spread across 3 components.
Roof ($12,000 ÷ 20 yrs)
$50.00/mo
Water heater ($1,800 ÷ 10 yrs)
$15.00/mo
Kitchen appliances ($3,500 ÷ 12 yrs)
$24.31/mo
Monthly reserve by component
Roof
$50.00/mo
Water heater
$15.00/mo
Kitchen appliances
$24.31/mo
Estimate based on your inputs. Not a promise of results.
Estimate only. This is planning arithmetic on your own cost and timeline assumptions — real replacement costs change, things fail early or last longer, and it ignores interest earned on the reserve and inflation.
How it works
How this tool works.
The expenses that wreck a rental’s cash flow are rarely the monthly ones — they’re the roof, the furnace, the water heater that all seem to fail in the same bad year. A capital-expenditure reserve is the standard defense: instead of absorbing a five-figure surprise, you set aside a steady monthly amount so the money is already there when the component gives out.
This calculator sizes that set-aside from your own list. Add a row for each big-ticket component with what it will cost to replace and how many years away you think that is — the starting rows are editable examples, not lifespan guidance. The tool spreads each cost over its timeline and sums them into one suggested monthly number. It’s planning arithmetic on your assumptions, nothing more.
Make the result useful
Separate major replacements from routine repairs
A CapEx reserve spreads your own estimated replacement costs over time. It is a planning fund for major components, not a prediction that every item fails on schedule.
Use inspection findings and contractor input to revise costs and timing.
Is this maintenance?
It is for major replacement planning, not routine repairs.
Should inflation be included?
Consider it separately when setting your assumptions.
Questions landlords ask
Questions about this tool and its limits.
Built by a landlord who's done every one of these jobs by hand.
Aptoria was built by an owner-operator managing a Brooklyn portfolio — the 11pm calls, the awkward rent texts, the April receipt-pile — not by a software team guessing at the problem.
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