Mortgage Pre-Approval Calculator
Estimate your mortgage pre-approval amount based on income, debts, credit score, and down payment. Check your DTI ratios, document readiness, and get strategies to strengthen your application before applying.
Pre-qualification and pre-approval are very different. Know which one you have and what it means to sellers.
How to Use This Mortgage Pre-Approval Calculator
Enter your income, debts, credit score, down payment, and employment history to estimate your pre-approval amount and readiness to apply. This calculator uses standard DTI guidelines used by most lenders.
Quick Calculator
Enter your Annual Gross Income (all income sources before tax), Monthly Debt Payments (car loans, student loans, minimum credit card payments — not rent or utilities), your Credit Score, and Down Payment Saved. The calculator uses standard 28/36 DTI rules to estimate your maximum pre-approval amount, front and back-end DTI ratios, and a 4-factor readiness score.
Advanced: Documents and Application Strengthening
The Document Checklist shows which documents lenders require for pre-approval, with a readiness tracker. The Strengthen Application tab quantifies the impact of improving your down payment, reducing debt, and raising your credit score on your maximum purchase price.
Pro: Shopping Multiple Lenders and Letter Strategy
The Multiple Lenders tab explains how to shop 3-5 lenders within the 14-day credit inquiry window with no extra score impact. The Letter Strategy tab covers how to present your pre-approval letter to maximize seller confidence.
How Pre-Approval Amount Is Calculated
Front-End DTI Limit (28% rule):
Max Housing Payment = Monthly Income × 28%
Back-End DTI Limit (36-43% rule):
Max All-Debt Payment = Monthly Income × 36-43%
Max Housing Payment = Max All-Debt − Existing Monthly Debts
Effective Max Housing = lower of front-end or back-end limit
Max Loan = Effective Max Housing × [(1+r)^n − 1] / [r × (1+r)^n]
(where r = monthly rate, n = term in months)
Max Home Price = Max Loan + Down Payment
Lenders use different DTI thresholds: conventional loans typically allow up to 43% back-end DTI, FHA allows up to 50% with compensating factors, and VA/USDA can go higher with strong credit. Use 36% as a conservative benchmark and 43% as the maximum most lenders approve.
Example: Pre-Approval in Nashville, TN
James and Amanda — dual income household
| Combined Annual Income | $130,000 |
| Monthly Income | $10,833 |
| Monthly Debts (car + student loans) | $650 |
| Credit Score | 745 (Very Good) |
| Down Payment | $65,000 |
| Front-End Max (28%) | $3,033/mo |
| Back-End Max (36%) | $3,900 − $650 = $3,250/mo |
| Effective Max Housing | $3,033/mo |
| Max Loan (6.75%, 30yr) | $468,000 |
| Max Home Price | $533,000 |
| Back-End DTI | 34.4% (strong) |
James and Amanda received pre-approval in 2 days. They shopped 4 lenders and found rates ranging from 6.625% to 7.0% — saving $97/month by choosing the best lender over the worst.