Real Estate Investing Calculators

Rental reserves.

A rental reserve is money set aside each month for the costs that do not arrive monthly: vacancy, routine repairs and big replacements such as the roof or furnace. Enter your rent, your repair assumption and the cost and life of major items below to get the monthly total. Runs in your browser; nothing is sent or stored.

Your numbers

Monthly rent

Vacancy allowance

Property value

Routine repairs per year (% of property value)

Roof: cost to replace

Roof: expected life (years)

Furnace and A/C: cost to replace

Furnace and A/C: expected life (years)

Water heater: cost to replace

Water heater: expected life (years)

Flooring and paint: cost to replace

Flooring and paint: expected life (years)

Appliances: cost to replace

Appliances: expected life (years)

The 1% of value for routine repairs is a common rule of thumb, not a published standard: set it from your building’s age and condition. For replacements, enter what each costs and how many years it lasts. Leave unused rows at zero.

Result

Fill the form and press Calculate.

Not financial advice. This is an estimating tool built on the numbers you enter. Real estate returns depend on assumptions that can be wrong; check them with a lender, an accountant and local sources before you buy.

Worked example

Rent $2,200 with a 5% vacancy allowance is $110.00 a month. Routine repairs at 1% of a $300,000 value are $250.00 a month. Replacements: roof $12,000 over 25 years, furnace and A/C $7,500 over 18, water heater $1,500 over 12, flooring and paint $6,000 over 10, appliances $4,000 over 12 add $162.92 a month. Total reserve $522.92 a month ($6,275.00 a year), 23.8% of rent.

How it works

Vacancy reserve = rent x vacancy %. Repair reserve = property value x repair % / 12. Capex reserve = sum of (cost / expected life in years / 12) for each item. Total = the three added together. These are budgeting figures from your own assumptions; real costs arrive unevenly, so keep the reserve in a separate account.

Sources and basis

BiggerPockets describes vacancy rate as the percentage of a year a property will sit empty and calls it a very important figure to include when you buy a rental property. The repair percentage is a common rule of thumb, not a published standard.

3 Approaches to Finding an Area’s Average Vacancy Rate (BiggerPockets), opened 2026-10-08.

FAQ

How much should I set aside for rental repairs?

There is no published figure. A common rule of thumb is about 1% of the property value a year for routine repairs, and more for older buildings. Use your own inspection and history.

What is a capex reserve?

Money saved monthly for big replacements that happen every decade or two, such as a roof, furnace, water heater or flooring. Divide each item’s cost by its life in years and by 12.

How do I choose a vacancy allowance?

Use local data and your own history. The calculator takes any percentage and multiplies it by rent.

Is the reserve an expense on my taxes?

No. A reserve is savings. Tax treatment depends on what you actually spend; check with an accountant.

Does the reserve count in NOI?

Lenders and appraisers handle replacement reserves differently. Many NOI figures leave them out, so put the monthly reserve into your own cash-flow plan.