Refinance Break-even Calculator

What this calculator is, and when to reach for it

Every refinance begins with a bill and ends, if you are lucky, with a saving. The break-even point is the month those two finally meet. Before it, switching has cost you money. After it, every payment is genuinely ahead. It is the most useful single number in the entire decision, and the one most often left out of a sales conversation.

The reason it matters so much is that mortgages are long and lives are not. A refinance that saves a fortune across thirty years is worthless to someone who moves in eighteen months, because they will never reach the point where the costs were recovered. The rate on offer tells you nothing about that. Only the break-even month does.

The arithmetic is deliberately simple: divide what switching costs by what you save each month, and you have the number of months to recover it. What takes judgement is the comparison that follows, between that number and an honest estimate of how long you will really keep this loan.

Use this page whenever a refinance is on the table, whenever discount points are offered, and any time someone presents a monthly saving without mentioning what it cost to obtain.

Being honest about your horizon

People systematically overestimate how long they will keep a mortgage. Jobs move, families grow, relationships change, and rates fall again prompting another refinance. The relevant horizon is not the term of the loan but the shorter of how long you will stay in the property and how long before you next refinance.

A useful discipline is to ask what has happened in the last seven years of your life and whether the next seven look more settled. If break-even lands comfortably inside a horizon you would bet on, the decision is easy. If it lands near the edge, the refinance is a gamble on your own stability rather than on interest rates.

Where the two are close, favour the lower-cost option even at a slightly worse rate. A refinance with minimal fees breaks even almost immediately and is forgiving if plans change; one with heavy costs demands that everything goes to plan for years.

Where to go next

This page isolates the timing question. For the full comparison of two loans, including total interest and the effect of any term change, use the refinance calculator, and to rank loans over a chosen horizon the mortgage comparison calculator.

To build an accurate cost figure rather than guessing at it, the closing costs calculator itemises what switching involves. If discount points are part of the offer, the points calculator runs the same break-even logic on the decision to buy the rate down.

Check the pricing you can access first with the loan to value calculator, see where you stand today with the amortization calculator, and if a lower payment rather than a lower rate is the real goal, the recast calculator may reach it far more cheaply. The refinance journey puts the sequence together.

How the break-even point is worked out

One division, and then a comparison that only you can make.

break-even months = total switching costs ÷ monthly saving

total switching costs

every fee to arrange the new loan, plus any exit charge on the old one

monthly saving

the current payment less the new payment, principal and interest only

Counting the costs properly

Include everything: arrangement and application fees, valuation, legal work, searches, any recording or registration charges, and discount points if you are buying the rate down. Add any prepayment penalty on the loan you are leaving, which borrowers routinely forget and which can move break-even by a year or more.

Costs financed into the new balance still count. Choosing not to pay them today does not make them disappear; it defers them and adds interest, so the honest calculation includes them at full value.

Why a term change corrupts the calculation

Break-even relies on the monthly saving being real. If the new loan also stretches the term, part of that saving is simply money moved into the future, and the break-even month it produces will be flatteringly early.

The clean comparison is between loans of the same remaining term. Where the terms differ, treat break-even as a rough guide only and judge the deal on total interest across your horizon instead, using the refinance calculator.

Why you may see two different break-even months

The straightforward division treats the whole payment difference as a saving. But part of a lower payment at a lower rate is not saving at all: it is principal you are repaying faster, which becomes equity rather than disappearing to a lender. A fuller measure counts the true cost of each loan and gives the new one credit for that, which produces an earlier break-even.

On the worked example above, the simple method says 26.8 months while the fuller method says month 21. Neither is wrong; they answer slightly different questions. The simple version asks when your cash outlay is recovered. The fuller version asks when your overall position is better.

It also ignores what the money spent on fees might have earned had it stayed invested, which pushes in the opposite direction. For most decisions none of this matters: if break-even is two years and you are staying ten, no refinement changes the answer. It matters only when the result lands close to your horizon, and there the honest conclusion is usually that the deal is marginal.

Reading the result

Under about two years is generally comfortable for anyone reasonably settled. Two to four years demands genuine confidence about staying. Beyond five years, the refinance is betting on a long stretch of stability and on rates not falling again in a way that would prompt another switch.

A very long break-even is not automatically wrong, but it should prompt a question: are the costs unusually high, or is the saving unusually small? Either answer is worth investigating before proceeding.

What this page assumes

The calculator compares cumulative fixed-rate schedule cash flows instead of dividing costs by the first payment difference.

Upfront costs occur at period zero and financed costs are included only in the proposed loan principal.

Worked examples, step by step

Take a borrower with 300,000 outstanding at 7% and 300 months remaining, offered 5.8% over the same term with 6,000 of switching costs.

Finding the break-even month

Two figures, and the difference between them is worth understanding. The simple division gives just under 27 months. This calculator reports month 21, because it compares the true cost of each loan rather than the payments alone, and credits the new loan for repaying principal faster at the lower rate. Money that goes to your balance instead of the lender is not a cost, and counting it as one makes the refinance look worse than it is.

The simple figure is therefore the conservative one, and that is no bad thing when you are deciding. If the deal works on the pessimistic measure it certainly works on the generous one. For anyone expecting to stay five years or more, this is a straightforward yes on either. For someone who may move within two years, it is a no however attractive the 1.2 percentage point rate improvement appears.

Note how little the rate itself tells you. The same rate improvement on a much smaller balance would produce a smaller monthly saving against similar fixed costs, pushing break-even years further out.

The same deal across a seven-year horizon

Assume the borrower stays seven years. Total savings are 223.94 × 84 = 18,811.24, and after the 6,000 of costs they finish 12,811.24 ahead. Roughly 57 of the 84 months are pure profit.

This is the framing worth carrying into the conversation. Not "the rate is 1.2% lower", but "I expect to be ahead by about 12,800 over the period I actually plan to be here."

When the answer flips

Suppose the same borrower faces a 3,000 exit charge on the existing loan, taking total costs to 9,000. Break-even moves to 9,000 ÷ 223.94 ≈ 40.2 months, more than three and a half years. A deal that was comfortable at 27 months now requires a substantially longer commitment.

Nothing about the rate changed. This is why forgetting a single cost line is the most consequential mistake on this page, and why the exit charge on the loan you are leaving deserves checking before anything else.

The vocabulary, on and around this page

Break-even point

The month at which accumulated savings equal the cost of switching. Before it you are behind; after it, ahead.

Switching costs

Every fee involved in moving loans, including arrangement, valuation, legal work, points, and any exit charge on the old loan.

Monthly saving

The current payment less the new payment. Only meaningful as a saving when the terms are comparable.

Horizon

How long you realistically expect to keep the loan, which is the shorter of staying put and refinancing again.

Prepayment penalty

A charge for repaying the existing loan early. Frequently forgotten, and capable of moving break-even by a year or more.

Closing costs

The fees required to complete the new loan. They form the numerator of the break-even calculation.

Financed costs

Fees rolled into the new balance rather than paid in cash. They still count in full, and they accrue interest.

Discount points

An optional up-front payment to lower the rate, where one point is one percent of the loan. It has its own break-even.

Term reset

Restarting the loan over a fresh full term, which inflates the apparent monthly saving and distorts break-even.

Total interest

All interest across the life of a loan. The better test when terms differ between the two loans.

Note rate

The rate the payment is built from, as distinct from the APR which bundles certain fees for comparison.

APR

A single comparison figure combining rate and certain costs. Useful for ranking offers, not for computing payments.

No-cost refinance

A refinance where fees are covered by accepting a higher rate. Break-even is immediate, but the ongoing saving is smaller.

Streamlined refinance

A reduced-documentation process under some programmes, usually with lower costs and therefore an earlier break-even.

Recast

Re-amortizing an existing loan after a lump sum. Where the goal is only a lower payment, it avoids switching costs entirely.

Loan to value

The loan as a percentage of the property value. It determines what pricing is available and therefore the size of any saving.

Opportunity cost

What the money spent on fees could have earned elsewhere. Ignored by the simple calculation, and minor unless break-even is marginal.

Equity position

How much of the property you own outright. A fuller comparison of two loans looks at this rather than payments alone.

Rate and term refinance

A refinance changing rate or term without releasing cash. Usually the cheapest kind and the fastest to break even.

Underwriting

The lender’s full reassessment of a new application. Costs are typically incurred before the outcome is known.

Common mistakes, and what this page will not do

• Leaving out the exit charge on the current loan. A prepayment penalty belongs in the costs. In the worked example, a 3,000 charge pushes break-even from 27 months to over 40.
• Comparing loans with different terms. A stretched term inflates the monthly saving and produces a flatteringly early break-even. Compare like terms, or judge on total interest.
• Treating financed costs as if they were free. Rolling fees into the balance defers them and adds interest. They belong in the calculation at full value.
• Overestimating how long you will stay. The relevant horizon is the shorter of staying put and refinancing again. Most people assume longer than reality delivers.
• Assuming a lower rate always justifies switching. The same rate improvement on a small balance produces a small saving against similar fixed costs, pushing break-even years out.
• Forgetting that break-even ignores the balance. Two loans can share a break-even month while building equity at different speeds. Check total interest as well.
• Proceeding when break-even is marginal. If the result lands close to your horizon, the deal is a bet on your own plans rather than on rates. Favour lower-cost options there.
• Ignoring a no-cost option. Covering fees through a slightly higher rate breaks even immediately, which can win outright for anyone with a short horizon.
• Counting escrow changes as savings. Tax and insurance moving between accounts is not a saving. Compare principal and interest only.

What this calculator leaves out: This calculator divides the costs you enter by the monthly saving you enter. It does not verify any lender’s fees or rates, model taxes or investment opportunity cost, account for term differences between loans, compare equity positions, or assess whether you would be approved. Where the two loans have different terms, judge the decision on total interest rather than this figure alone.

Frequently asked questions