The $600K Refinance Numbers
Refinance analysis on $600K mortgage balance
| Current Rate | New Rate | Monthly Savings | Closing Costs | Break-Even | 10-Year Savings |
|---|---|---|---|---|---|
| 7.5% | 6.5% | $402/mo | $15,000 | 37 months | $33,240 |
| 7.0% | 6.2% | $316/mo | $15,000 | 47 months | $22,920 |
| 6.5% | 6.0% | $201/mo | $15,000 | 75 months | $9,120 |
The $600K balance makes every 0.1% rate improvement worth roughly $40/month. A 1% rate reduction saves $402/month — $4,824/year — making refinancing math work quickly even with substantial closing costs.
In 2025, the conforming loan limit in most areas is $766,550. A $600,000 balance falls within conventional conforming limits in most markets — qualifying for lower conforming rates. In some counties (the lower-limit baseline is $726,200), a $600K loan may need jumbo treatment depending on the area. Check your county’s specific limit.
Tax Deductibility at $600K
Mortgage interest on loans up to $750,000 is deductible if you itemize deductions. At $600,000, the full interest deduction is available. This reduces the effective cost of the mortgage — at a 22% marginal tax rate, $36,000 in annual interest produces a $7,920 tax benefit. Factor this into the true cost comparison.
Should You Refinance to 15 Years on $600K?
15-year vs. 30-year refinance on $600K balance — total interest comparison
| Option | Monthly Payment | Total Interest (Life) | Payoff |
|---|---|---|---|
| $600K, 7.0%, 30-yr remaining | $3,993 | $837,200 | 30 years |
| $600K, 6.2%, 30-yr refi | $3,661 | $718,600 | 30 years |
| $600K, 5.8%, 15-yr refi | $4,998 | $299,600 | 15 years |
Calculate Your $600K Refinance Savings
Large balance, large stakes. Run the numbers before deciding.