Closing Costs Calculator

Itemise the costs of completing a UK residential purchase: stamp duty, conveyancing, survey and any other one-off fees, using 2024/25 SDLT rates.

freeworks offlinenothing uploaded
Input
Output
—

About closing costs calculator

Closing Costs Calculator is a small tool that does one job while you watch. Nothing is saved, so a reload gives you a clean start.

There is no account and no upload step. Whatever you paste lives in a variable until you close the tab, and then it does not.

You will find it under Property, alongside 12 other tools for the same sort of job.

Runs in this tab, so nothing you type is uploaded.

How to use it

01
Start it
Every control is on the tool itself. Keyboard shortcuts, where there are any, are listed beside it.
02
Watch it run
It updates in the page as you go. Nothing is sent anywhere, so it keeps working with the network off.
03
Close when done
Nothing is stored between visits. Reloading gives you a clean start rather than picking up where you left off.

Examples

A 250,000 buy-to-let purchase
Solicitor and survey at typical amounts, plus 300 of other costs
Input
propertyPrice: 250000
buyerType: additional
legalFees: 1500
surveyFee: 500
mortgageArrangementFee: 0
otherCosts: 300
Output
Stamp duty land tax: 7500
Legal fees: 1500
Survey fee: 500
Mortgage arrangement fee: 0
Other costs: 300
Total closing costs: 9800
Total closing costs percent of price: 3.92

Questions

Does Closing Costs Calculator work offline?+

Yes. It is JavaScript running in this tab, so once the page has loaded it needs nothing further from the network. Put the machine in flight mode and it carries on. Nothing you do here is sent anywhere, because there is nowhere for it to go.

Does it remember anything between visits?+

No. Reload the page and it starts from nothing. There is no account, no saved state and no cookie holding your last session. That is a deliberate trade: it cannot lose your data because it never keeps any.

Is it accurate?+

Timing comes from performance.now(), the high resolution clock the browser provides, rather than from setInterval, which drifts by a few milliseconds every tick and compounds over minutes. What can still shift things is the browser throttling a tab in the background, so leave it visible if the timing matters.

Does it make a sound?+

Where a sound makes sense, it is generated with the Web Audio API rather than loaded as a file, so there is nothing to download and nothing to block. Browsers refuse to start audio until you have interacted with the page, which is why the first press is what switches it on.

Can I use Closing Costs Calculator on a phone?+

Yes. The controls are sized for touch and the layout collapses to one column on a narrow screen. Bear in mind that a phone locking its screen will suspend the page, and timing stops with it.