$1,265/mo
Principal & Interest
A $300,000 mortgage at 3% interest over 30 years costs approximately $1,265 per month in principal and interest. This assumes no down payment adjustment — if you're buying a $375,000 home with 20% down, the loan amount would be $300,000.
At 3%, property taxes and homeowner's insurance typically add $300–$600/month, bringing total housing costs to roughly $1,565–$1,865/month.
Calculate Your Exact Payment →The figures above use a $300,000 loan at 3% over 30 years. Your situation may differ — use the Mortgage Calculator to plug in your actual home price, down payment, and rate to get a personalized result.
At 3%, you repay roughly $1.52 for every $1 borrowed over the full 30-year term. This is among the lowest interest-to-loan ratios you'll see on a 30-year mortgage — rates near 3% were common in 2020–2021 but are well below typical historical averages.
Small rate changes have a meaningful impact on monthly cost and total interest. Here's how a $300,000 loan compares across rates:
| Interest Rate | Monthly P&I | Total Interest (30yr) | vs. 3% |
|---|---|---|---|
| 3.0% | $1,265 | $155,332 | — |
| 4.0% | $1,432 | $215,609 | +$167/mo |
| 5.0% | $1,610 | $279,767 | +$345/mo |
| 6.0% | $1,799 | $347,515 | +$534/mo |
| 7.0% | $1,996 | $418,527 | +$731/mo |
Moving from 3% to 7% on the same $300K loan adds $731/month and costs an additional $263,000 in total interest. If you locked in a 3% rate, you're saving substantially compared to today's borrowers.
See detailed payment breakdowns at different home prices — each page includes rate comparisons, down payment tables, and term comparisons.
Browse all 37 price points on the Mortgage & Real Estate hub.
At 3% interest over 30 years, a $300,000 mortgage costs approximately $1,265/month in principal and interest. With taxes and insurance, expect a total payment of $1,565–$1,865/month depending on location.
Over the full 30-year term, you'll pay approximately $155,332 in total interest, bringing your total repayment to $455,332. That's roughly 52% of the original loan added in interest — far less than the 100%+ you'd pay at rates above 6%.
Rates near 3% were available during 2020–2021 but have since risen substantially. As of early 2026, 30-year fixed rates are significantly higher. If you already have a 3% mortgage, it's worth holding — refinancing would almost certainly raise your rate. Use the mortgage calculator to compare your current payment against what you'd owe at today's rates.