Waitlist open ยท 0%

Stack the non-resident surcharge, additional property, and first-time buyer relief in one calculator. See your real SDLT before you exchange.

Stack every SDLT surcharge and relief in one figure. Solicitor-ready breakdown with legislation references, before you exchange contracts.

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Bring a friend who'd use this. Each signup pulls the launch closer.

See it live

$4.99 lifetime ยท or $19 / month SaaS ยท no charge today

๐ŸŒ Web toolยทfinance

Built by someone who already shipped 30+ tools

30+
tools shipped
2,300
weekly Google impressions
35d
day-by-day streak
12
ranked in top-10

For a sense of what shipped looks like: relly.permissionlabs.com โ†—

What it does

Every surcharge, every relief, one figure.

Click any card to jump to its deep dive below.

Who it's for

Built for these decisions.

If any of these are your question, this is the tool.

Foreign national buying first London flat

Do I owe the 2 percent surcharge if I move in before completion?

โ†’ Run the 183-day window against your travel dates. See the exact resident-status flag the calculator applies and the SDLT delta both ways.

UK resident buying a second property

What does the 3 percent stack actually look like on a ยฃ750K flat?

โ†’ Type the price. See base SDLT, the 3 percent surcharge component, and the total. No spreadsheet, no HMRC table cross-check.

Off-the-plan buyer with a 14-month completion

Which SDLT rates apply, the rate at exchange or at completion?

โ†’ Toggle the effective date. See both figures with the legislation reference for the rule that picks between them.

First-time buyer in a couple where one partner owns elsewhere

Does first-time relief still apply if my partner owns a flat?

โ†’ Set the joint-buyer flag. See which relief applies and which surcharge is triggered, with the band-by-band reasoning.

The problem

HMRC publishes one SDLT table. Your real bill is six tables stacked.

HMRC publishes one stamp duty table. The real bill is six tables on top of each other. A foreign national buying a second London flat off the plan pays the base SDLT band, plus the 3 percent additional property surcharge, plus the 2 percent non-resident surcharge, minus the first-time buyer relief if any leg applies, minus the off-the-plan concession in some cases. No public calculator stacks all of these. The HMRC tool runs the base table only. Most agent calculators stop at the 3 percent flag. A solicitor will run the full sum, two weeks in, after you have already paid the holding deposit. By then the surprise is a five-figure budget hole, not a planning input. The cost is not the tax. It is committing on a number that does not include the two surcharges that double it.

What you'd get

Four pieces, one tool.

Each piece ships in the first build for waitlist members. SaaS upgrades layer on top.

01 ยท feature

Six surcharges and reliefs stacked in one figure

Base SDLT band, 3 percent additional property, 2 percent non-resident, first-time buyer relief, multiple dwellings relief, shared ownership staircasing. The calculator applies the rules in order, shows each component as a line item, and prints the final SDLT. Other tools cap at the base table.

Trust signal scorecard
47
  • Real founder photo
  • Real testimonials with photos
  • OKSpecific metrics with units
  • Custom typography
  • OKCustom design tokens
  • Social proof above the fold
  • OKFooter with company details
02 ยท feature

Non-resident 183-day window engine

Type your travel window for the 12 months before completion. The 183-day rule runs against the dates and returns the resident-status flag the surcharge uses. Most foreign buyers assume citizenship sets the flag. It does not. Timing does.

Scenario picker
03 ยท feature

Effective date and off-the-plan path picker

Off-the-plan completion can fall under the SDLT rate at exchange or at completion depending on the contract clause. Toggle the effective date. See both SDLT figures with the SDLT manual section that controls the choice. Saves a solicitor call.

Inflation drift
Inflation3.0%
Cliff edge
year 22
04 ยท feature

Solicitor-ready PDF export

One page. Property price, every surcharge component, every relief applied, the band rate behind each line, and the legislation reference per row. Bring it to your conveyancer or use it for budget planning. SaaS upgrade tier.

Saved scenarios
  • Default plan
    Survives 40y
  • 2008 stress
    Year 17
  • Aggressive draw
    Year 11
  • Conservative
    Survives 40y
  • + Save current scenarioSaaS
Why paid

Today's tools don't do this.

A missed 2 percent non-resident surcharge on a ยฃ750K London flat is ยฃ15,000 of unbudgeted SDLT, discovered two weeks into the transaction. A misread off-the-plan effective date can move the bill by another ยฃ5,000 to ยฃ20,000. A conveyancer's SDLT review is ยฃ200 to ยฃ500 and runs only after exchange. Hourly opportunity cost on the cash held in deposit is real.

โœ—Base SDLT band only. No 2 percent non-resident surcharge. No off-the-plan effective date toggle. No solicitor-ready export.
Their pricing
โœ—Adds the 3 percent flag for additional property. Skips non-resident, skips off-the-plan, skips multiple dwellings relief.
Their pricing
โœ—Marketing widget on a listing page. Base table plus 3 percent. No legislation reference, no export.
Their pricing
Conveyancing solicitor manual quote
โœ—Accurate, but quoted two weeks into the transaction, after the holding deposit. Fee is ยฃ200 to ยฃ500 for the SDLT review.
Their pricing
UK Stamp Duty Surcharge
โœ“Every surcharge and relief stacked ยท Resident status by travel window, not citizenship ยท Off-the-plan effective date picker ยท Solicitor-ready PDF with legislation references
$4.99
Price anchor
Compared to
1-hour solicitor SDLT review
Their price
$200~500 / hour
What you get
Run every component before exchange. Same band-by-band breakdown your conveyancer would build, $4.99 once, runs forever.
โœ“
What you get now

SDLT stack with 2 percent non-resident, 3 percent additional property, first-time buyer relief, multiple dwellings relief, and off-the-plan effective date toggle. Solicitor-ready PDF export. Travel-window engine for the 183-day test.

โ†—
What's coming

Saved transactions, multi-property portfolio mode, joint-buyer split sheets, Scotland LBTT and Wales LTT engines on the same UI. SaaS upgrade tier ($19/month).

ยท
What's not included

Legal advice on transaction structure. Conveyancing. Tax advice for non-domiciled status, IHT planning, or company purchases. For those, retain a solicitor or chartered tax adviser.

Pricing

Which price would get you on the waitlist?

No charge today. The click tells me which tier is real demand. Early access price โ‰  launch price.

Join the waitlist

Want this built?

Drop your email. No charge, no spam. You're saying "yes, I'd actually use this." That's the signal I'm looking for.

Hi, I'm Hyunyoung.

Solo builder ยท Choppy Toast

This page is a quick vibe-coded probe to test demand and gather feature requests. The actual product, when it ships, will be a polished, hand-built tool, not this scaffold.

For a sense of what "polished and shipped" looks like, here's another product I built: relly.permissionlabs.com.

FAQ

Honest answers.

Then I wait. The waitlist stays live forever, no expiry, no archive. The faster you bring a friend mid-purchase right now, the faster I ship it. That is the whole engine.

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