
Online accounting in real time in Lengwil: rules, deadlines, best practice
Whether you run a Sàrl, an SA or a sole proprietorship in Lengwil, online accounting eventually lands on your desk. Here are the practical reference points — legal basis, deadlines and common pitfalls — to decide with a clear head.
Digitalising online accounting: what actually works
A serious accounting document archive links every record to its entry, timestamps versions and logs access — exactly what Swiss bookkeeping regulation expects from probative electronic retention. Chronological filing by financial year becomes an automatic by-product.
The winning pair for online accounting: a single inbox (e-mail, scan, photo) and one simple rule — no document sits more than a few days without a proposed entry.
The Swiss legal frame for online accounting
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.
Art. 957a CO requires complete, truthful and systematic recording of transactions, each entry backed by a supporting document. For online accounting, that means in practice: no movement without a receipt, and an audit trail that can be reconstructed at any time — including during a VAT or AHV inspection.
Outsource online accounting or keep it in-house?
Outsourcing does not exempt you from understanding: an owner who can read the balance sheet and the income statement challenges the fiduciary better — and pays for advice, not re-keying.
A clear mandate agreement states who does what by when: document handover, posting deadlines, filing calendar, and responsibility for delays. A shared platform (same data, same document archive) between the company and its fiduciary eliminates binder ping-pong and duplicate entry.

QR-bills and friction-free collections
The QR-bill is generated from the accounts, not the other way round: the document is born with its reference, amount and due date already linked to the receivable entry — a clear win for SMEs in Lengwil.
For the debtors of a business in Lengwil, nothing changes on the payer's side: scan the code, confirm, pay. On the online accounting side, everything changes: the collection entry proposes itself, the receivables ledger updates continuously and reminders go out on exact balances.
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.
Federal deadlines do not move in Lengwil: VAT within 60 days, salary declaration in January, 10-year record retention — postal code 8574 changes nothing about those rules, only the sender's address.
Frequently asked questions
When must a business register for VAT?
As soon as its worldwide annual turnover reaches CHF 100,000 (CHF 250,000 for non-profit sports or cultural associations). Below that, voluntary registration remains possible and often makes sense to reclaim input VAT on investments. The threshold is federal: it applies in Lengwil as everywhere in Switzerland.
Which social contributions does a Swiss employer pay?
AHV/IV/APG: 5.3% employer share (the same is withheld from the employee); unemployment insurance: 1.1% each up to CHF 148,200 a year; occupational pension (LPP) by age and plan (employer at least 50%); occupational accident insurance paid by the employer; family allowances by canton. For an employer in Lengwil, family allowances follow the canton's rates.
What are the legal obligations for online accounting 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.
Do you need a fiduciary for online accounting, or can you do it yourself?
Both are defensible. Below CHF 500,000 of revenue, a sole proprietorship may keep simplified accounts itself. As soon as payroll, VAT and a closing with tax stakes are involved, professional support prevents mistakes that cost more than the fees. With a shared platform, the fiduciary does not even need to be in Lengwil.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates online accounting 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.