What Is CapEx Reserve?
A CapEx reserve is money set aside from rental income to cover eventual big-ticket replacements — roof, HVAC, water heater — that don't happen every year but are certain to happen eventually.
CapEx Reserve in plain English
A capital expenditure reserve is money you set aside from each month's rent for big replacements - roof, furnace, water heater, flooring - that do not happen every year but are certain to happen eventually.
The most reliable way to size it is to divide each major component's replacement cost by its remaining life and add them up.
Worked example
A reserve budget for a $2,000-a-month rental
Illustrative example - round numbers, not current market data. Calculated with Reaixo's calculator engines.
Assumptions
- Rent
- $2,000 a month
- Expected vacancy
- 3 weeks a year between tenants
- Routine maintenance and repairs
- 8% of rent (illustrative)
- Roof replacement
- $12,000 every 25 years
- Furnace and AC replacement
- $9,000 every 18 years
- Water heater replacement
- $1,800 every 12 years
- Flooring and paint replacement
- $6,000 every 8 years
| Step | Calculation | Result |
|---|---|---|
| 1. Vacancy allowance | $2,000 × 12 ÷ 52 × 3 weeks | $1,385 (5.8%) |
| 2. Maintenance allowance | $24,000 × 8% | $1,920 |
| 3. Capital reserve (cost ÷ life, summed) | $12,000 ÷ 25 + $9,000 ÷ 18 + $1,800 ÷ 12 + $6,000 ÷ 8 | $1,880 |
| 4. Total yearly set-aside | $1,385 + $1,920 + $1,880 | $5,185 |
Set aside each month: $432. About $432 of every $2,000 rent payment (22%) should be treated as already spent. Budgeting from the property's own components and local turnover is more reliable than a single rule of thumb.
What this calculation leaves out
- Component costs and lifespans are illustrative; use quotes and the age of the actual systems.
- Reserves are for expected wear; keep a separate emergency fund for surprises such as a sewer line.
Try it: CapEx Reserve with your own numbers
Interactive and illustrative: change any value and the results update instantly in your browser. The figures come from the same engines as REAIXO's full calculators.
From rent to cash flow: the NOI waterfall
Gross rent shrinks at every step: vacancy, operating expenses, the mortgage and reserves. NOI is the property's income before financing; cash flow is what you keep.
- Net operating income
- $23,454
- Per year, before the mortgage
- Estimated cash flow
- $3,064
- $255 a month
- Cap rate on the price
- 7.33%
Show the numbers as a table
| Step | Per year | Per month |
|---|---|---|
| Gross scheduled income | $36,000 | $3,000 |
| Vacancy and credit loss | −$1,800 | −$150 |
| Effective gross income | $34,200 | $2,850 |
| Operating expenses | −$10,746 | −$896 |
| Net operating income | $23,454 | $1,955 |
| Debt service (principal and interest) | −$18,680 | −$1,557 |
| Capital-expenditure reserve | −$1,710 | −$143 |
| Estimated cash flow | $3,064 | $255 |
Formula
Effective gross income = Gross scheduled income − VacancyNOI = Effective gross income − Operating expensesCash flow = NOI − Debt service − Capital-expenditure reserveAssumptions
- 30-year fixed loan, no points; one unit with no other income, HOA or utilities.
- Vacancy is taken off gross rent; management, maintenance and the capital-expenditure reserve are a share of collected rent.
- The capital-expenditure reserve sits below NOI: it is cash set aside, not an operating expense.
- Income taxes, depreciation and appreciation are left out.
Why it matters
Skipping a CapEx reserve makes a property's cash flow look better than it really is; a common rule of thumb sets aside 5-10% of rental income for future capital items.
Without a reserve, a single replacement can wipe out years of cash flow and force borrowing at a bad time.
Common mistakes
- Relying on a flat percentage for an old building.
- Spending the reserve on routine repairs.
- Ignoring component ages found in the inspection.
Compare and common questions
CapEx Reserve: frequently asked questions
How much should I set aside for capital expenditures?
Base it on the property: replacement cost divided by remaining life for each major component. Percentage-of-rent rules are a rough starting point only.
Are capital expenditures tax deductible?
Not all at once. Improvements are generally depreciated over time rather than deducted in the year paid; ask a tax professional.
Related Terms
Where it fits
- Investing, Rehab: before this, Permit; next stage, Leasing & Operations: Gross Rental Income.
More Investing Terms
Recommended next step
Build a component-based reserve.
How much to budget for vacancy and maintenance →Sources and review
- Publication 527, Residential Rental Property, Internal Revenue Service. Supports: Improvements to rental property are depreciated rather than deducted as expenses.
Where this applies: Not regulated. Investment ratios and budgeting conventions are industry practice; lenders and analysts may define inputs differently.
Last reviewed: · Updated:
Examples use illustrative figures; rules of thumb are labelled as such. Rates, limits and program rules change - confirm current figures with your lender or a qualified professional.
This definition is provided for general educational purposes and is not financial, legal, tax, or real estate advice. Verify important decisions with appropriately qualified professionals.
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