
SME chart of accounts for engineering firms in Lengwil: rules, deadlines, best practice
Swiss accounting law (art. 957 ff. of the Code of Obligations) sets a precise frame, yet day-to-day practice often stays fuzzy. This guide walks through what actually matters for a business based in Lengwil.
The Swiss legal frame for SME chart of accounts
Responsibility for the books is personal: in an SA, organising the accounting is one of the board's non-transferable duties (art. 716a CO); in a Sàrl, the managing directors carry the same duty. Outsourcing the execution never transfers that underlying responsibility, including for a company based in Lengwil.
The good news: the Swiss frame is stable and predictable. Structure SME chart of accounts once — chart of accounts, document flow, calendar — and the same organisation pays off for years.
A Swiss SME's accounting calendar
January: salary declaration to the compensation office and salary certificates. End of February, May, August, November: quarterly VAT returns (effective method), each to be filed and paid within 60 days after the quarter ends. Within six months of year-end: approved annual accounts. Then: the tax return under cantonal deadlines, with extensions possible.
For SME chart of accounts, year-end is prepared in October: last invoices, investment decisions, provisions to assess — December is too late to act, January is for recording.
A well-structured SME chart of accounts
Shareholder current accounts demand strict hygiene: every private withdrawal documented, interest at the rates accepted by the tax administration, and a clean-up at closing.
In an SME in Lengwil, the chart of accounts is also a delegation tool: clear posting rules let a non-accountant prepare most entries without error.

Digitalising SME chart of accounts: what actually works
Digitising does not mean hoarding PDFs: without the document-entry link, a digital file is as opaque as a box of archives — true in Lengwil as everywhere.
For SME chart of accounts, migrating history must not block the start: begin on day one of the current financial year and import the history later if needed.
Lengwil: what changes, what does not
Working with a fiduciary from Lengwil no longer depends on geography: the documents of a business in Lengwil are shared online, while the canton Thurgau keeps its own deadlines for the tax return.
Lengwil requires no special bookkeeping: the Code of Obligations applies at postal code 8574 as everywhere else, and a well-kept digital file transfers smoothly to any auditor in the canton.
Frequently asked questions
What are the current Swiss VAT rates?
Since 1 January 2024: 8.1% (standard), 2.6% (reduced — for example food and medicines) and 3.8% (accommodation). Returns must be filed and paid within 60 days after the period ends (quarterly under the effective method, semi-annually under the net tax rate method). These federal rates apply unchanged in Lengwil.
Can SME chart of accounts be automated with AI?
Largely, yes: automatic document reading, posting suggestions, bank reconciliation via QR references and VAT exports. Human approval remains essential — AI prepares, the professional checks. That is exactly how MyFiducia.ai approaches SME chart of accounts.
Does MyFiducia.ai work for a business based in Lengwil?
Yes: the platform runs online, the rules applied are federal (VAT, CO, AHV), and the file can be shared with any fiduciary. A business in Lengwil manages its documents, VAT and exports exactly as anywhere in Switzerland.
What are the legal obligations for SME chart of accounts in Switzerland?
The foundation is the Code of Obligations: proper bookkeeping (art. 957a CO), annual accounts (balance sheet, income statement, notes) and 10-year retention of books and records (art. 958f CO). VAT applies from CHF 100,000 of turnover, and social insurance settlements from the first employee. Nothing is different in Lengwil: federal law applies.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates SME chart of accounts for businesses in Lengwil: AI-read documents, posting suggestions, VAT and exports ready for your fiduciary. Try the platform or browse our other guides.
The application is operated in French.