Built by someone who runs these calculations on real client files.
One adviser, one paraplanner-flavoured spreadsheet too many, one HMRC brief most firms have never read closely.
Harry Dunn
Harry is an IFA at Perspective Financial Services with day-job experience running pension annual allowance, carry-forward, and chargeable-event-gain calculations on live client files. ParaplanAI began as the spreadsheet he stopped trusting after one too many compliance-officer queries about HMRC Brief 12/2021.
The tool is built and operated by a single adviser. The calc engine is deterministic TypeScript that runs end-to-end on uploaded provider documents; AI is used only to extract figures from PDFs (P60s, PSS, bond statements) under a user-review gate. Every figure on every compliance annex is replayable to the pence twelve months later.
If you spot a calc that's wrong, email hello@paraplanai.co.uk — full re-derivation against HMRC PTM / IPTM corpus on the next working day.
Why a calc tool, not a workspace.
Existing adviser back-office systems handle the workflow well. What they don't do — and what HMRC's own published calculator still gets wrong on top-slicing relief — is the post-2021/22 personal-savings-allowance recalculation at Step 4. Misstating that line costs the client between £200 and £40,000+ in misreported tax, depending on where the gain pushes adjusted income.
ParaplanAI is narrow on purpose: pension annual allowance + carry-forward + tapered AA + MPAA, plus investment-bond chargeable-event gain + top-slicing relief with the post-2021/22 PSA recalc. The output is a branded compliance annex an adviser drops directly into a client file.
The product spec, the calc-engine rules, and the operating manual are all on GitHub. Read the trust story for the audit-grade build (HMRC corpus, property-based tests, GPT-5 tripwire).
Get in touch.
Spotted a calc error, want to discuss firm pricing, or have a feature request? Email goes straight to Harry.