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.
Bring a friend who'd use this. Each signup pulls the launch closer.
$4.99 lifetime ยท or $19 / month SaaS ยท no charge today
Built by someone who already shipped 30+ tools
For a sense of what shipped looks like: relly.permissionlabs.com โ
Every surcharge, every relief, one figure.
Click any card to jump to its deep dive below.
Built for these decisions.
If any of these are your question, this is the tool.
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.
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.
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.
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.
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.
Four pieces, one tool.
Each piece ships in the first build for waitlist members. SaaS upgrades layer on top.
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.
- 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
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.
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.
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.
- Default planSurvives 40y
- 2008 stressYear 17
- Aggressive drawYear 11
- ConservativeSurvives 40y
- + Save current scenarioSaaS
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.
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.
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).
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.
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.
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.
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.
More upcoming tools.
Extension Listing Kit
SaaS
Upload each screenshot, promo tile, and description once. We resize and crop every image to the exact spec the Chrome Web Store, Firefox Add-ons, and Edge Add-ons each ask for, hold one copy of your name, summary, and description per store and per language with the character limit checked as you type, and run a pre-submit pass that names every missing or out-of-spec asset before you hit publish.
Video Bloat Audit
Web tool
Paste a URL. We find every autoplay and background video on the rendered page, show the real transfer weight and how much each one adds to your largest paint, estimate the monthly bandwidth bill at your actual traffic, and hand you a ranked plan to swap each clip for a poster, a lazy load, a smaller encode, or a scripted animation.
Decompound Calc
Web tool
See exactly when your retirement money runs out.
AI Stack Cost
SaaS dashboard
One dashboard for every AI subscription you forgot about.
Vibe Check
Web tool
Find every AI-generated tell on your landing page.
Account Stack 2026
Web tool
Tell us your income. We tell you exactly where to put each dollar across 401k, Roth IRA, HSA, and backdoor.
Ad Precheck
Web tool
Paste your ad copy, image, and landing URL. Get a per-platform rejection score for Meta, Google Ads, and AdSense before you submit.
Silent AI Audit
Mac app
Find every AI model silently installed on your Mac. See the size, last access, and how to remove each one.
EV Power Bill
Web tool
See your real EV charging bill before you buy the car.
Before You Install
Web tool
Paste a package. See the supply-chain risk before you run install.
LLM Self-host Cost
Web tool
See if self-hosting an LLM actually beats the API bill.
App Store Precheck
Web tool
Paste your app metadata, screenshots, and Info.plist. Get a per-guideline rejection score before you hit Submit for Review.
Vibecode Audit
Web tool
Find the 12 security holes Cursor, Lovable, v0, and Bolt leave open by default. Paste your URL, get a report your investor will not flag.
Spice Graveyard
iOS app
Scan the spice rack once. Get told what to cook tonight with the bottles you already own, and stop buying duplicates.
Home Addition Cost
Web tool
Paste a contractor bid for your home addition. Get a line-by-line read on what is fair, what is padded, and what scope cut drops the total without losing the room.
Accutane Tracker
iOS app
Log your Accutane course like the dermatologist would. Daily lip dryness, side-effect severity, dose ladder, blood-draw reminders, and a photo timeline that shows where week 12 actually got you.
PIH Fade Plan
Web tool
Tell us your skin type, breakout history, and how much post-acne brown is left. Get a 16-week active routine that switches between azelaic, niacinamide, vitamin C, and tretinoin based on how your skin actually reacts in week 2, 4, 8, and 12.
Tailwind Exit Plan
Web tool
Paste a Tailwind component or a repo URL. Get a structured CSS migration plan that pulls out reusable classes, scaffolds CSS modules with design tokens, and hands the team a 4-week refactor schedule with the file to open on Monday.
VMware Exit Plan
Web tool
Paste your VMware renewal quote, host counts, and license SKUs. Get a per-hypervisor cost split across Proxmox, Hyper-V, OpenShift, and Nutanix, the migration hour estimate, and a 90-day cutover schedule that names the cluster to drain first.
Child Investment Planner
Web tool
Type your kid's age, your monthly budget, and your tax bracket. Get a side-by-side projection for 529, UTMA, and Roth IRA at age 18, the contribution that fits your budget, and the one-page memo that names the account to open first.
RMM Escape Plan
Web tool
Paste your NinjaOne invoice, endpoint count, and add-on list. Get your real all-in per-endpoint cost, a dated cancellation letter that respects the 60-day notice clock, and a migration matrix scored to your size across Action1, Level.io, Endpoint Central, and Syncro.
Bank Freeze Exit Plan
Web tool
Type your monthly cash flow, your balance range, and your current business bank. Get a freeze-risk score for every provider, the morning-of runbook if your account locks, a named backup account at a second institution, and a one-page memo for your bookkeeper.
Host Lock-In Escape
Web tool
Paste your host, plan tier, and what you deploy. Get a lock-in risk score across Netlify, Vercel, Render, Fly.io, and Cloudflare Pages, a redeploy config built from your own env vars and redirects, and a one-page runbook for the morning your account gets suspended with the site still live.
After-Death Money Checklist
Web tool
Tell us the state and the rough size of the estate. Get whether you can skip full probate, which bills you actually have to pay and which die with the person, the order to notify the banks and the agencies, and a one-page memo for the family.
Heat Safety Planner
Web tool
Tell us who is going outside, what they are doing, and your zip code. Get a clear go, modify, or cancel call for today's heat, the work-rest and water schedule for those conditions, the early heat-illness signs to watch in that specific person, and the safe hours to move it to.
5 more on the waitlist and I build this.
No charge today. Drop your email, lock in the early-access price, and you hear first when it ships.
Built by a real person. No silent vaporware.
