The 30-Year Rate Premium Table
True cost of rate premiums on a $400,000, 30-year mortgage
| Rate vs. 6.0% Baseline | Monthly Premium | 10-Year Cost | 30-Year Cost |
|---|---|---|---|
| 6.25% (0.25% premium) | $57/mo | $6,840 | $20,520 |
| 6.5% (0.5% premium) | $115/mo | $13,800 | $41,400 |
| 7.0% (1.0% premium) | $230/mo | $27,600 | $82,800 |
| 7.5% (1.5% premium) | $349/mo | $41,880 | $125,640 |
The table shows the cumulative payment difference. The actual interest cost difference is slightly different due to amortization, but the premium cost is concrete: accepting a 1% higher rate costs $82,800 over a 30-year loan life on $400K.
A 680 vs. 760 credit score produces approximately a 0.7% rate premium in 2025. On a $400,000 loan over 30 years: $57,960 in additional interest. The 6-month effort to improve credit from 680 to 760 — paid credit card balances, no new accounts — returns $57,960. Few financial improvements offer this return per unit of effort.
Where Rate Premiums Come From
Rate premium sources and elimination strategies
| Rate Premium Source | Typical Rate Impact | How to Eliminate |
|---|---|---|
| Credit score below 740 | +0.3–0.7% | Improve credit 6 months before applying |
| LTV above 80% | +0.1–0.5% | Pay down to 20% equity or eliminate PMI |
| Only shopping one lender | +0.15–0.5% | Get 3–5 quotes |
| Not negotiating fees | +0% rate, higher costs | Use competing LEs to negotiate |
| Jumbo loan vs. conforming | +0.1–0.5% | Structure loan to stay below conforming limit |
The 30-Year NPV of Shopping
Spending 3 hours getting 5 lender quotes can save 0.25–0.5% on your rate. On $400K over 30 years, 0.3% savings = $24,720. That’s $8,240 per hour of rate-shopping effort — one of the highest-return activities in personal finance.
See What Your Current Rate Is Costing You
Compare your rate to alternatives and see the true long-term cost difference.