How much more does a 7% mortgage cost vs 4%?

On a $300,000 30-year mortgage: 4% costs $215,600 in total interest. 7% costs $418,500. That's $202,900 more — roughly $563/month extra for 30 years. The 3-point rate gap nearly doubles your total interest.

Why is the 4% vs 7% comparison relevant in 2026?

Many 2020-2022 buyers locked in rates around 3-4%. Current 2026 buyers face 6.5-7%+. This comparison quantifies the difference between those eras and helps buyers with older low-rate mortgages decide whether to sell, refinance, or stay put.

Should I sell my house with a 4% mortgage?

Only if the move is necessary for non-financial reasons. On a $300K mortgage, going from 4% to 7% adds $563/month and $202,900 in total interest. That's why so many homeowners are staying put — the 'golden handcuffs' of a low-rate mortgage are financially real.

Rate Comparison Updated May 2026 10 min read

4% vs 7% Mortgage Interest — What Three Points Actually Costs You

Q: Can overpayments offset a 7% rate?

Partially. $300/month extra at 7% on $300K saves $100,000 in interest and cuts 10 years. That brings your effective cost closer to a 5% scenario, though not fully down to 4%. Overpayments are the best tool available when refinancing isn't an option.

This comparison hurts to read if you're buying in 2026. On a $300,000 mortgage, the difference between 4% and 7% is $202,900 in total interest — roughly $563 more per month for 30 years. If you locked in at 3.5% in 2021 and your neighbor buys the same house in 2026 at 7%, they'll pay nearly double the total cost. The tables below show every loan amount, and you can model your own rate scenario here.

Monthly payment at 4% vs 7%

This isn't an abstract comparison. Millions of American homeowners locked in 3–4% rates during 2020–2022. Today's buyers face 6.5–7%+. Here's what that gap looks like in real monthly payments on a 30-year term:

Loan Amount	4% Monthly	7% Monthly	Difference
$200,000	$955	$1,331	+$376/mo
$250,000	$1,194	$1,663	+$469/mo
$300,000	$1,432	$1,996	+$564/mo
$350,000	$1,671	$2,329	+$658/mo
$400,000	$1,910	$2,661	+$751/mo

On a $350,000 mortgage, 7% costs $658 more per month than 4%. That's roughly $7,900 per year in additional housing cost — enough to fund a solid vacation, max out a Roth IRA, or make a significant dent in other savings goals. And this is just the payment difference, not the total interest cost difference.

Total interest: where three points becomes devastating

Monthly payment is annoying. Total interest over 30 years is where the comparison gets genuinely alarming.

📊 Total interest — 4% vs 7% over 30 years

$250K at 4%$179,700 interest

$250K at 7%$348,800 interest (+$169,100)

$300K at 4%$215,600 interest

$300K at 7%$418,500 interest (+$202,900)

$400K at 7%$558,000 interest (+$270,200 vs 4%)

A $400,000 mortgage at 7% costs $270,200 more in interest than at 4%. That's a quarter-million-dollar difference — more than enough to buy a second property in many markets. This is why the 2020–2022 cohort of mortgage holders have what the industry calls "golden handcuffs." Their low rate is worth hundreds of thousands of dollars.

The golden handcuffs dilemma

Got a 4% mortgage and thinking about moving? Here's the calculation most homeowners face in 2026:

Selling means giving up that 4% rate. Your next mortgage will likely be 6.5–7%. On the same loan amount, that adds $500–$750/month to your housing cost. Even if you're moving to a cheaper market, the rate increase often eats the price difference.

This is why housing inventory is historically low in 2026. Homeowners aren't selling because they'd lose a rate that saves them $200,000+ over the remaining loan term. It's rational behavior that has frozen a significant portion of the housing market.

Can overpayments offset a 7% rate?

Partially. If you're stuck at 7%, overpayments are your best tool for reducing the total cost. Here's how $300/month extra changes a $300,000 mortgage at 7%:

Without extra payments: $418,500 total interest, 30-year payoff. With $300/month extra: $318,500 total interest, 20-year payoff. That $300/month reduces your effective total interest by $100,000 — bringing the cost closer to what a 5% mortgage would cost over 30 years. It doesn't fully offset the rate gap, but it meaningfully narrows it.

If this comparison feels relevant to your situation, the 5% vs 6% breakdown and 6% vs 7% comparison cover smaller gaps that might match where you are now. And if you're stuck at 7% with no refinancing in sight, the refinance vs overpay guide helps you figure out the best move. The overpayment calculator lets you model any combination.

Current rates tracked by Freddie Mac's weekly survey. For understanding how rate lock-in is reshaping the housing market, NAR's housing data has the best research.

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4% vs 7% Mortgage — Questions

How much more per month is 7% vs 4%?

On $300,000: about $564/month more. On $400,000: about $751/month more. The gap scales linearly with loan amount.

Should I sell my house to avoid losing my 4% rate?

The financial case for keeping a 4% mortgage is very strong. Only sell if life circumstances require it. A 4% rate on $300K saves you $202,900 vs 7% over 30 years. That's hard to justify giving up for a slightly bigger kitchen.

Will mortgage rates drop back to 4%?

Most economists consider 3–4% rates from 2020–2022 historically unusual, driven by pandemic-era monetary policy. Rates may ease to 5.5–6% but returning to 4% would require another significant economic disruption. Plan around current rates.

Can I assume a seller's low-rate mortgage?

Only on FHA, VA, and USDA loans — conventional mortgages are generally not assumable. Mortgage assumption lets you take over the seller's rate and remaining balance. It's worth investigating but adds complexity to the transaction.

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Team OverpayCalc.com

We built these tools because the difference between mortgage rates isn't just math — it's life decisions. Our job is to make the numbers clear so you can make them with confidence.

Educational content only. Estimates use standard amortization. Market conditions, rates, and housing prices change frequently. Consult a financial advisor before making major housing decisions.