What This Calculator Does
The tool models a renter investing the cash that would otherwise have been used for the down payment and purchase costs. Each month, whichever housing scenario costs less is modeled as investing the difference.
The buyer’s ending position combines estimated home equity after entered selling costs with any invested monthly differences. The renter’s ending position is the modeled investment account. The comparison does not label either choice as universally better.
Worked example
A short ownership period can make purchase and selling costs especially important. A longer period may allow more principal reduction and home-value change, but repairs, taxes, insurance, maintenance, and uncertain appreciation continue to affect the result. Changing the comparison from five years to ten years can materially change the modeled outcome.
Formula and Methodology
The mortgage uses fixed-rate amortization. Home value, rent, insurance, HOA dues, and investment balances change monthly using the entered annual assumptions. Property taxes and maintenance are estimated as percentages of the modeled home value.
At the end of the selected period, estimated buyer equity equals modeled home value minus the remaining loan balance and entered selling costs. The calculator then compares estimated ending positions.
Assumptions and Limitations
Assumptions
- The mortgage is a fully amortizing fixed-rate loan with consistent scheduled payments.
- Annual growth and return assumptions are applied evenly even though real markets and expenses change irregularly.
- The renter is modeled as investing available upfront cash and positive monthly cost differences.
- Utilities are excluded because both renters and owners may pay them differently.
What It Cannot Determine
- The tool cannot predict home appreciation, rent changes, investment performance, repairs, or selling costs.
- It excludes income-tax effects, itemized-deduction eligibility, renter deposits, moving costs, and many transaction-specific adjustments.
- It does not measure lifestyle flexibility, job stability, repair responsibility, neighborhood plans, or personal risk tolerance.
- A higher modeled ending position is not a recommendation to rent or buy.
Frequently Asked Questions
How many years should I compare?
Use the period you realistically expect to remain in the home or area, then test shorter and longer scenarios. Buying and selling costs can matter more over short periods.
Why does the appreciation assumption matter so much?
Future home value directly affects estimated equity and selling proceeds. Because appreciation is uncertain, compare conservative, flat, and stronger-growth scenarios instead of relying on one forecast.
Does the calculator include repairs?
The maintenance percentage is an editable allowance for ongoing maintenance. It cannot predict the timing or cost of a roof, heating system, plumbing, or other major repair.
Does a higher buyer result mean I should buy?
No. The result reflects only the entered financial assumptions. Personal stability, flexibility, property risk, and professional guidance also matter.
Official Sources
The methodology and terminology were checked against the following primary government resources. Loan Under Review is not affiliated with or endorsed by these agencies.
Related Mortgage Calculators
Related Mortgage Guides
This calculator provides an educational estimate based on the information and assumptions entered. It is not a loan estimate, rate quote, appraisal, preapproval, approval decision, financial recommendation, or commitment to lend. Actual program requirements, qualifying calculations, rates, fees, insurance costs, taxes, and lender practices may differ.
Last reviewed: by the Loan Under Review Editorial Team.