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For accountants

Run client books, with the paperwork built in.

Workpapers, engagement letters and authority-response letters, generated and country-aware. Built so a practice can run more than one client's books.

Start free trialSee how it works

See /for-accountants/pricing

accounts-os.com/practice
Practitioner ToolsLive
Draft an engagement letter for a new GB client
FDrafted, ICAEW-toned and ready to send. Want the CT600 workpaper too?
FFinn drafted it country-aware, no template hunting.
Live

In short

For accounting practices, AccountsOS includes: a practice-mode sandbox for demos and training, a workpaper generator (Excel) with VAT 9-box and CT600 (with marginal relief) packs, an engagement-letter drafter aware of professional bodies (ICAEW, ACCA, ACA, CIMA, CIOT, AAT for GB; CPA IE, CCAB IE, CAI for IE; ICPA BG; FTA AE), an advisory-memo generator (4–6 page year-end pack), and authority-response letter drafting for HMRC / Revenue / NRA / FTA enquiries.

Excel
Workpapers
10+
Pro bodies covered
4
Tax authorities

Everything it does

Practice mode sandbox

  • Demo company with pre-seeded data
  • Training environment for new staff
  • Risk-free way to demo to a prospect
  • Reset to seed any time

Workpaper generator (Excel)

  • VAT 9-box workpaper
  • CT600 workpaper with full computation
  • Marginal relief calculation worked through
  • Adjustments column for disallowables and capital allowances
  • S455 director-loan impact pulled in
  • Audit trail per adjustment
  • More document types on roadmap (Word, PDF)

Engagement letter drafter

  • Country-aware: GB, IE, AE, BG
  • Professional bodies: ICAEW, ACCA, ACA, CIMA, CIOT, AAT (GB); CPA IE, CCAB IE, CAI (IE); ICPA BG; FTA AE
  • Service-scope picker (bookkeeping, payroll, VAT, CT, advisory)
  • Fee structure capture (fixed, hourly, retainer)
  • Word + PDF output
  • GB model wording included at launch

Advisory memo generator

  • 4–6 page year-end advisory memo
  • Executive summary
  • P&L review with prior-period comparison
  • Balance sheet review
  • Tax position analysis
  • Prioritised recommendations
  • Word + PDF output

Authority response letters

  • Drafts replies to tax authority enquiries
  • Multi-country: HMRC (GB), Revenue (IE), NRA (BG), FTA (AE)
  • Tone selection: professional, concise, detailed
  • Penalty notices flagged for adviser escalation

Capabilities at a glance

Practice mode sandbox with reset

VAT 9-box workpaper (Excel)

CT600 workpaper with marginal relief (Excel)

Country-aware engagement letter drafter

10+ professional bodies covered

Advisory memo generator (4–6 pages)

Authority response letters for HMRC / Revenue / NRA / FTA

Lead pipeline for accounting practices

Public B2B section (/for-accountants)

How It Works

1

Run client books

Each client is a trading entity. You can manage many in one login.

2

Generate workpapers

VAT 9-box and CT600 (with marginal relief, S455, audit trail) export to Excel for client filing.

3

Draft engagement letters

Country and professional-body aware. Service scope and fee structure captured. Word + PDF output.

4

Year-end memo

Advisory memo with executive summary, P&L review, BS review, tax position, prioritised recommendations.

By the numbers

CT600
With marginal relief
The 19–25% banded calc done correctly
4-6 page
Advisory memo
Year-end client pack on demand
GB / IE / AE / BG
Tone-aware letters
HMRC / Revenue / FTA / NRA

Real-world Use Cases

Onboarding a new client

Generate the engagement letter (ICAEW model wording, fixed fee, scope = full bookkeeping + VAT + CT). Send for client signature.

Year-end CT600

Generate the workpaper with marginal relief and S455. Review with the client. File via HMRC.

HMRC enquiry letter

HMRC asks about a 2024 expense claim. Draft a professional, concise response with citations from your AccountsOS audit trail.

Year-end advisory memo

Generate a 4–6 page memo for each client. Send before their year-end meeting.

Plays nicely with

Excel

Live

Workpapers in XLSX with formulas intact.

Word

Live

Engagement letters and memos in DOCX.

PDF

Live

All practitioner documents available as PDF too.

Why founders pick this over the spreadsheet

Cut hours off the engagement-letter and workpaper grind

Standardise quality across staff (ICAEW-grade output)

Country-aware so multi-jurisdiction practices don't reinvent letters

Practice-mode keeps demos and training risk-free

Advisory memo gets generated in minutes, not days

Frequently Asked Questions

What workpapers do you generate?

Today: VAT 9-box and CT600 (with marginal relief, S455, capital allowances, audit trail) for the UK. Excel format with formulas intact. CT1 (Ireland), corp tax workpapers for AE / BG on roadmap.

What professional bodies are covered for engagement letters?

GB: ICAEW, ACCA, ACA, CIMA, CIOT, AAT. IE: CPA IE, CCAB IE, CAI. BG: ICPA. AE: FTA. Each has the appropriate model wording and clauses.

What does the advisory memo cover?

4–6 pages: executive summary, P&L review with prior-period comparison, balance sheet review, tax position analysis, and prioritised recommendations. Word + PDF output.

Are the authority response letters compliant?

They're drafts informed by AccountsOS audit data, structured for the relevant authority's tone (HMRC, Revenue, FTA, NRA). The accountant remains responsible for review and submission.

Is there an accountant-specific pricing tier?

Yes. See /for-accountants/pricing for the practice tier, which includes multi-client management and these practitioner tools.

Can I run client demos safely?

Yes. Practice mode is a sandbox with seeded data you can demo or train staff in, then reset.

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Financial Reports

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International Tax

UK-deep. International-aware. Run a Ltd, an LLC and a free-zone company side-by-side.

Ready to try Practitioner Tools?

Set up in minutes. Finn works in the background on your books, wherever you're based.

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Accountant pricing tier: see /for-accountants/pricing.

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