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Mortgage & Home Financing

Calculate mortgage payments, refinancing, HELOC, and home affordability

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Mortgage and Home Financing Workflow

A home purchase is typically the largest financial transaction most people will ever make. The financing decision — down payment, loan type, rate vs points trade-off — has a compounding effect over the loan term. Even a 0.5% rate difference on a $400K mortgage changes total interest paid by over $40,000 over 30 years.

Step 1: Set a Realistic Affordability Range

Mortgage lenders use the 28/36 DTI rule: your housing payment should be under 28% of gross monthly income, and total debt payments under 36%. The Home Affordability Calculator works backward from income, existing debts, and down payment to estimate the maximum loan amount a lender will approve. Building in a cushion below that maximum — ideally 10-15% — protects against rate increases, maintenance costs, and financial emergencies.

Step 2: Calculate the True Monthly Payment

The mortgage payment isn't just principal and interest. Property taxes, homeowner's insurance, and PMI (if down payment < 20%) add significantly to the monthly outlay. A $300K loan at 6.5% has a $1,896 P&I payment, but total PITI (principal, interest, taxes, insurance) on a $350K home in a moderate-tax area is often $2,400-$2,600. The Mortgage Calculator shows the full payment breakdown including an amortization schedule.

Step 3: Evaluate Refinancing Opportunities

Refinancing makes sense when the rate reduction saves enough in monthly payments to recoup the closing costs within a reasonable timeframe. The Refinance Break-Even Calculator shows the exact break-even month. For a 1% rate reduction on a $300K loan with $6,000 in closing costs, break-even is typically 18-24 months — meaning refinancing makes sense if you'll stay 3+ years.

Frequently Asked Questions

How much house can I afford on a $100,000 salary?

Using the 28% front-end DTI guideline: $100,000 gross annual / 12 = $8,333/month × 28% = $2,333 max housing payment. At 6.5% over 30 years, $2,333 monthly supports approximately $370,000 in loan principal. Add your down payment to get the max purchase price. Actual approval depends on your other debts, credit score, and lender criteria.

When should I refinance my mortgage?

General rule: refinance when you can reduce your rate by at least 0.5-1% and you plan to stay long enough to recoup closing costs. The Refinance Break-Even Calculator shows your exact break-even month. If you'll move or sell before break-even, refinancing costs more than it saves. High-rate environments can create refinancing opportunities as rates drop — watching the break-even period is more important than any single rate threshold.

What is PMI and how do I avoid it?

PMI (private mortgage insurance) is required by most conventional lenders when your down payment is under 20%. It typically costs 0.5-1.5% of the loan amount annually, added to your monthly payment. To avoid it: put 20% down, use an 80/10/10 piggyback loan structure, or accept PMI and eliminate it once you reach 20% equity (lenders are required to cancel at 22%). The PMI Removal Calculator shows when you'll hit the elimination threshold.

Are mortgage discount points worth buying?

Each point costs 1% of the loan amount and typically reduces your rate by 0.25%. On a $300K loan, 1 point costs $3,000 and might save $45/month. Break-even is $3,000 / $45 = 67 months (5.5 years). Buying points only makes financial sense if you're certain you'll keep the loan longer than the break-even period — which is uncertain given refinancing and mobility.

What is the difference between a HELOC and a home equity loan?

A HELOC (Home Equity Line of Credit) is a revolving line — you can draw, repay, and redraw during the draw period (typically 10 years), with variable interest rates. A home equity loan is a lump sum at a fixed rate repaid over a fixed term. HELOCs are better for unpredictable ongoing expenses. Home equity loans are better for a specific large expense where you want payment certainty.