What's your locked-in mortgage rate actually worth?
Debating whether to sell your current home and move? If you bought or refinanced in 2020 or 2021, your low rate isn't just a nice memory — it has a real, calculable dollar value that belongs in that decision. This tells you what yours is worth, what moving would actually cost, and how to weigh that against the reasons you're considering it.
Optional: model an actual move
Where this number comes from
This uses the same net-present-value methodology Freddie Mac's own economists use to estimate the lock-in effect across their portfolio. The idea: your locked-in rate has a real dollar value equal to the difference between your outstanding balance and what that same stream of payments would be worth if discounted at today's market rate. In Freddie Mac's own published example — a $236,379 balance at 2.65%, refinanced against a 6.81% market rate — the lock-in value came out to $86,136.
Freddie Mac estimates the national average lock-in value at roughly $55,000 per household as of their most recent portfolio analysis, with the highest concentrations among loans originated in 2020–2021.
Why this number matters more than it might seem
Because most mortgages aren't assumable or portable, giving up your rate is essentially permanent once you sell — there's no way to bring a 3% rate to your next home. That's what makes this a genuine, quantifiable cost of moving, not just an abstract inconvenience. Research from UC Irvine and UC Berkeley economists found this effect discouraged an estimated 800,000 household moves in a single year during the 2022–2023 rate spike.
Using this to actually decide: should you sell and move?
This calculator is built for exactly that question, not just "what's my rate worth" in the abstract. Once you've run the numbers above, here's how to turn them into a decision rather than just a sobering statistic.
Check the new payment against your income
Run the "new home payment" figure through our affordability calculator or DTI calculator using your actual income. If it pushes you past the standard 28%/36% thresholds, that's worth knowing before you fall in love with a listing — regardless of how manageable the dollar increase feels in isolation.
Price the benefit, not just the cost
The lock-in value and payment increase are concrete numbers. Put a number on the other side too: what's a shorter commute, more space, or being near family actually worth to you per month? It won't be as precise, but forcing yourself to estimate it keeps the comparison honest rather than one-sided.
Weigh how long you'd stay
A large lock-in value matters less if you're confident you'd stay in the new home 10+ years — the cost amortizes over more time. If you might move again in 2–3 years, you're paying to give up your rate twice: once now, and again on the next sale.
Consider the middle options
Before deciding it's "stay" or "sell," weigh renovating, an addition, or the keep-and-rent strategy below. The full lock-in value only applies if you give up the loan entirely — some paths let you keep it.
When moving is still worth it anyway
This number is a real cost, not a verdict. A few situations where moving can still make sense despite a large lock-in value:
- A job change or relocation that meaningfully increases income can outweigh a higher payment within a few years.
- Outgrowing the space — a growing family in a two-bedroom condo faces real costs from staying too, they're just not visible on a mortgage statement.
- Life changes like divorce, elder care, or health needs that a spreadsheet can't capture.
- A shorter time horizon — if you'd only stay 2–3 more years anyway, the ongoing monthly savings from staying matter less than they would over a decade.
The alternative most people don't consider: keep and rent
Rather than selling and losing the rate entirely, some homeowners keep their current home as a rental — carrying the low-rate mortgage on an income-producing asset — while buying their next home with a new, market-rate mortgage. This doesn't eliminate the higher payment on the new home, but it converts the "lost" low rate into a rental property with genuinely favorable financing, rather than giving it up entirely. It requires qualifying for two mortgages simultaneously and taking on landlord responsibilities, which isn't the right fit for everyone — but it's a real third option beyond "stay" or "sell."
What this calculator assumes
- Your current payment is principal and interest only — taxes, insurance, and HOA aren't part of the lock-in math, since they'd apply at either rate.
- The "full move" section assumes a 30-year term on the new mortgage, standard for most purchase loans.
- Today's market rate is something you should update to whatever current rates actually are — the default shown is illustrative, not a live quote.
The four questions most borrowers never think to ask
Published guidelines are not the rules you’re judged by. Your lender’s own credit policy is, and nobody publishes it. Get the question sheet:
- What to ask about DTI, with the number in it, so you get a number back
- How to find out whether a rule is the agency’s or the lender’s
- What a “no” actually means, and when to take the same file elsewhere
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Frequently asked questions
What is the mortgage rate lock-in effect?
It describes what happens when a borrower holds a mortgage at a rate well below the current market. Moving means giving that rate up and financing the next house at today's rate, so the low rate acts as a financial reason to stay put even when the house no longer fits. It is not a fee anyone charges you; it is an opportunity cost that shows up only when you compare staying against moving.
How is the dollar value of a locked-in rate calculated?
By comparing what you pay on the current loan against what the same remaining balance would cost at today's rate over the period you expect to stay, then expressing the difference as a total rather than a monthly figure. A monthly comparison understates it, because the gap compounds over the years you would hold the new loan.
Is it ever worth moving despite a high lock-in value?
Often, yes. The lock-in value is one number in the decision, not the decision. A job change, a growing household, a shorter commute, or proximity to family can be worth more than the rate differential, and a smaller or cheaper house can offset a higher rate outright. The point of quantifying it is to make the trade explicit rather than to settle it.