Lease Extension Calculator
Your landlord has offered to extend your rental lease, and the only number on the offer is a new monthly rent. That number settles nothing on its own: extending also means extension fees and a fresh deposit, while moving means market rent on a new place plus moving costs, a new deposit, broker and application fees. This calculator totals both sides over 3, 6 and 12 months, finds the break-even point, and gives a plain recommendation. It is for rented homes and apartments; the UK leasehold premium version of a lease extension is a different calculation, covered in the section below the tool.
Extension
Moving
Estimates for decision support, not financial advice. Annual increases compound at each 12-month boundary of the extension term. Confirm fees and terms with your landlord.
Quick Answer
On the pre-filled offer, extending wins clearly: a $1,575 extension for 12 months costs $18,900 all in, against $23,550 for moving to a $1,650 market rental once $3,750 of moving costs, deposit and application fees are counted. Extending saves $4,650 over 12 months, the extension rent sits $75.00 (4.5%) below market, and the break-even figure is 50 months. Change any figure above and the verdict updates with the same math.
Key takeaways
- Judge the decision on 12-month all-in totals, not the monthly rent. A cheaper monthly rent can still lose once deposits and moving bills land.
- Moving carries a one-off bill most renters undercount: in the worked example it is $3,750 before the first month at the new place.
- The recommendation always compares 12 months, whatever term you select. The total over your actual term is shown separately in the Extension column.
- This tool prices a rental extension against moving house. A UK leaseholder extending a leasehold flat is buying years from a freeholder, which is a valuation, not a rent comparison.
- Quick Answer
- How to use the lease extension calculator
- How the extend-or-move comparison is built
- Worked example: a $1,575 extension against a $1,650 market rental
- This is not the UK leasehold extension premium
- Before you sign the extension: five checks
- What competing calculators miss
- Frequently asked questions
- Add This Calculator to Your Website
- References
How to use the lease extension calculator
Fill in the offer on the left, the cost of the move on the right, then click Compare. Results stay hidden until you do.
- Current and new rent: enter what you pay now and the rent in the extension offer. Only the new rent drives the comparison; the current rent just produces the monthly change line.
- Term and annual increase: pick the extension length. If the offer steps the rent up each year, enter that percentage; it is applied once at each 12-month boundary, so it only changes the total over the term on extensions longer than a year. If your offer instead steps up by a fixed percentage on a set schedule, the lease escalation calculator models that clause on its own.
- Extension fee and new deposit: add anything the landlord charges to sign, and any top-up deposit. Both are counted in the extension totals as cash due.
- The moving side: enter the rent of a comparable place you would genuinely take, then the one-off costs: movers, the new deposit, any broker fee and application fees. Be honest here; a flattering market rent produces a flattering answer.
- Read the verdict: the headline compares 12 months of each option, the columns break down each side, and the lines below add the break-even point and the 3, 6 and 12-month costs. If you want to sanity-check the market rent against where rents are heading, the future rent calculator projects a rent forward at a yearly growth rate.
How the extend-or-move comparison is built
Each side is a simple stack: rent over the period, plus the one-off money that changes hands at signing. Nothing is discounted and nothing is hidden in a monthly average.
Moving total (12 months) = Market rent × 12 + Moving costs + New deposit + Broker fee + Application fees
Annual savings by extending = Moving total (12 months) − Extension total (12 months)
Break-even (months) = Upfront moving costs ÷ (Market rent − Extension rent), rounded up, shown only when market rent is higher
Verdict = Extend when the saving is positive; moving when it is negative by $500 or more; similar cost when moving is cheaper by less than $500
Three behaviours of this tool are worth knowing before you rely on it. First, the verdict and the savings line always use a 12-month horizon so the two options are compared fairly, even on a 24-month or month-to-month term; the Extension column separately shows the true total over the term you picked, increases included. Second, blank fields have defaults: a blank current rent counts as $1,500, a blank custom term counts as 18 months, and every other blank counts as zero, while a blank new rent or market rent stops the calculation with a message, because no comparison exists without them. Third, deposits are treated as cash due inside the totals, and the tool does not subtract the refund of your current deposit on either side, so read the totals as cash committed rather than money ultimately lost. Tenant deposit and notice rules vary widely by state and city; the U.S. Department of Housing and Urban Development's tenant rights hub links to the rules for each state.
Worked example: a $1,575 extension against a $1,650 market rental
The calculator is pre-filled with this exact case: current rent $1,500, extension offer $1,575 for 12 months with a 3% annual increase and no extension fee or extra deposit; the alternative is a $1,650 market rental with $2,000 of moving costs, a $1,650 new deposit and $100 of application fees. Every figure below is what the tool returns.
| Horizon | Extension | Moving | Difference |
|---|---|---|---|
| 3 months | $4,725 | $8,700 | $3,975 |
| 6 months | $9,450 | $13,650 | $4,200 |
| 12 months | $18,900 | $23,550 | $4,650 |
The moving column barely moves between horizons because $3,750 of it is paid once, up front. That is the whole story of most extend-or-move decisions: the monthly gap here is only $75, so the move needs 50 months of that gap just to absorb its own upfront bill, which is the break-even figure the tool reports. Draw the two 12-month totals as bars and the upfront weight is obvious:
One variation shows what the annual increase does. Keep everything the same but take a 24-month term: year one costs $18,900, then the 3% increase lifts the rent to $1,622.25 for year two, so the total over the term is $38,367 including no fees. The 12-month verdict does not change, because the verdict never looks past month 12; the term total is the number to weigh if you know you will stay the full two years.
This is not the UK leasehold extension premium
If you own a leasehold flat in England or Wales, stop here: your lease extension is a statutory purchase, not a rent negotiation, and this calculator does not price it. A UK extension under the Leasehold Reform, Housing and Urban Development Act 1993 adds 90 years at a peppercorn rent in exchange for a premium paid to the freeholder, built from the capitalised ground rent, the freeholder's deferred reversion, and, when fewer than 80 years remain, half the marriage value.
That premium needs valuation inputs this page never asks for: the flat's value, the years left on the lease, the ground rent, and deferment and yield rates. Our lease enfranchisement calculator takes exactly those inputs and estimates the premium on that statutory basis. Even then, treat any online figure as a planning range: the Leasehold Advisory Service's guidance on getting started with a lease extension sets out the formal notice process, and a RICS valuer's report is what negotiations actually run on. Nothing on this page is legal advice, for either kind of extension; rental extensions turn on your lease wording and local tenant law, and leasehold extensions turn on the 1993 Act procedure.
Before you sign the extension: five checks
Run these five checks in order once the numbers favour extending. Each one can change the offer you are being asked to sign.
What competing calculators miss
Most pages ranking for this keyword answer a different question, and the one tool that shares this page's intent stops halfway:
- The simple extension-cost tools (for example the 7Search calculator): they multiply rent by months and add a fee, then stop. No moving side, no break-even, no verdict, so the one comparison a renter actually faces is never made.
- The UK premium calculators (Survey Merchant, lease-extensions.org.uk and similar): solid statutory tools for leasehold flats, with deferment rates and relativity graphs, but useless to a renter: they ask for property values and ground rents, never for a market rent or a moving bill. The two intents share a keyword and nothing else, which is why this page names the difference in its first paragraph.
- Long-form guides with no tool (FasterCapital and similar): plenty of discussion of premiums and value uplift, aimed at owners, with no working calculator a renter can run an offer through.
- The gap this page fills: both decisions priced side by side on the same 12-month horizon, 3 and 6-month timelines for shorter stays, a break-even in months, a verdict that follows the arithmetic, and an honest statement of the tool's own defaults and deposit treatment.
Frequently asked questions
Compare the 12-month all-in cost of each option, not the monthly rent. If extending saves money after counting moving costs, deposits and fees, extend. In the worked example the extension costs $18,900 over 12 months against $23,550 for moving, so extending saves $4,650.
It divides your upfront moving costs by the monthly gap between the market rent and the extension rent. With $3,750 of upfront moving costs and a $75 gap, the result is 50 months: the time the rent gap alone would take to add up to the moving bill. The tool shows it only when the market rent is above the extension rent, and it reads as not applicable when your upfront moving costs are zero.
The tool applies your annual increase percentage once at each 12-month boundary of the extension term, compounding on the rent then in force. A $1,575 rent at 3% becomes $1,622.25 in year two, so a 24-month term totals $38,367 with no fees. The increase never changes the 12-month comparison, which is always the first year.
No. UK leasehold extensions value the freeholder's interest under the 1993 Act, including marriage value below 80 years remaining, which needs a professional RICS valuation. This tool compares extending a rental lease against moving. For the statutory premium, use a lease enfranchisement calculator with your flat's value, years remaining and ground rent.
Application and broker fees, the new deposit (often due before the old one is returned), overlap rent if the two leases cross, and time off work to move. Enter all of them on the moving side. On the extension side, the forgotten items are the extension fee itself and any deposit top-up the landlord asks for at signing.
It counts deposits as cash due inside the totals: the extension deposit in the extension total, and the new deposit inside the upfront moving costs. It does not subtract the refund of your current deposit on either side, so read the totals as cash committed during the move or signing, not money permanently lost.
Then no break-even figure is shown, because there is no monthly gap for moving costs to be weighed against, and the verdict turns on the 12-month totals alone. Moving can still lose if its upfront costs are large, or win outright; in one test case a $2,000 extension rent against a $1,650 market rent with no moving costs made moving cheaper by $4,200 over 12 months.
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References
- U.S. Department of Housing and Urban Development. Tenant Rights, Laws and Protections. Accessed October 22, 2026.
- Consumer Financial Protection Bureau. Help for Renters. Accessed October 22, 2026.
- Federal Trade Commission. Rental Listing Scams. Accessed October 22, 2026.
- Internal Revenue Service. Publication 527: Residential Rental Property. Accessed October 22, 2026.
- U.S. Bureau of Labor Statistics. Consumer Price Index: Rent of Primary Residence. Accessed October 22, 2026.
- U.S. Census Bureau. American Housing Survey. Accessed October 22, 2026.
- GOV.UK. Leasehold Property: Extending, Changing or Ending a Lease. Accessed October 22, 2026.
- Leasehold Advisory Service. Lease Extension: Getting Started. Accessed October 22, 2026.
- Leasehold Advisory Service. Lease Extension: The Formal Route (Leasehold Reform, Housing and Urban Development Act 1993). Accessed October 22, 2026.
- Royal Institution of Chartered Surveyors. Find a Surveyor: Leasehold Enfranchisement and Valuation. Accessed October 22, 2026.