Built by a paraplanner, for paraplanners.
A narrow tool that does two calculations to a regulator-defensible standard — and a branded compliance annex you can drop straight into a client file.
Two calculations, both load-bearing.
Pension annual allowance — including taper, carry-forward, and MPAA — plus investment-bond chargeable-event gain with top-slicing relief. That's the whole product. No lifetime cashflow, no CGT, no IHT, no client portal. Narrow on purpose.
The calc engine is pure deterministic TypeScript. Every rate, threshold, and allowance lives in a versioned tax-year config; every output stamps the config version, so a calc run today is replayable to the pence six years later. AI is used only inside the extraction layer — to pull figures from uploaded PDFs (P60s, pension annual statements, chargeable-event certificates) — and every extracted field passes a user-review gate before any maths runs.
The output is an A4 compliance annex with the full statutory working, the legislative reference for each step, the source documents that fed the calc, the tool version, the config version, and the planning-disclaimer on every page. How we verify the engine covers the HMRC corpus, the property-based tests, and the cross-LLM tripwire.
HMRC's own calculator gets one rule wrong.
IPTM3820 / HMRC Agent Update 83 (2021) changed the top-slicing relief calculation for gains arising on or after 6 April 2021. The personal savings allowance and the savings-rate band must be recalculatedat the notional-income level at Step 4 of the TSR algorithm. HMRC's own published tool, every spreadsheet template doing the rounds in adviser firms, and most of the calculators bundled into back-office systems still apply the pre-2021/22 method.
The misstatement on a single £100k bond gain can be anywhere from a few hundred pounds to over £40,000 of misreported tax, depending on where the gain pushes adjusted income. ParaplanAI applies the rule variant matching the gain's tax year — the Step-4 recalculation for gains from 6 April 2021, the carried-forward PSA/SRB method for earlier gains — and the annex states which variant was applied.
The same engine handles taper-AA, carry-forward, MPAA. The pension calc is less load-bearing than top-slicing, but every paraplanner who's carried a row of £40k / £60k / £10k / £4k thresholds across four prior tax years knows the spreadsheet drifts.
UK-hosted, six-year retention, no surprises.
The application is UK/EU-hosted, encrypted at rest and in transit. Client PII is encrypted at the application layer before storage; the calc engine never sees it. Uploaded source documents are permanently deleted 24 hours after upload; the output PDF is held for 30 days so it can be re-fetched.
Results are immutable and replayable. Retention is six years post-cancellation, aligned with FCA SYSC 9.
Sub-processors and the full data-processing addendum live on the trust page; the security posture and the disclosure process are on /security.
One paraplanner, building the thing they needed.
ParaplanAI is built and operated by a working UK paraplannerat a regulated UK firm. The product is intentionally narrow because it’s built by a single founder with hands-on paraplanning experience and a refusal to ship calc rules that aren't corpus-tested to the pence.
The product’s credibility rests on the open HMRC regression suiteand a 14-day HMRC-currency commitment, not on a personal brand. The operator’s identity is withheld here but available to professional bodies and prospective firms on request — including a named contracting party for a sub-processor DPA.
Compliance officers and prospective firms can email info@paraplanai.co.uk for the operator’s CV, references, IFA registration verification, or a screen-share walkthrough of the calc-engine corpus run.
Get in touch.
Spotted a calc that doesn't reconcile, want to discuss firm pricing, or have a feature request? Reply within one working day.