
Accounting software deadlines in Lengnau (AG): the practical guide
Accounting software deadlines in Lengnau (AG) raises the same questions for most Swiss SME owners: which obligations apply, which deadlines are running, which documents to prepare. This page covers the federal rules in force — without unnecessary jargon.
Digitalising accounting software: what actually works
The classic digitalisation traps are avoidable: scanning without quality control (unreadable records), stacking disconnected tools (double entry in disguise), or neglecting access rights. One single flow from document to entry, with clear roles, beats five shiny apps.
For accounting software, migrating history must not block the start: begin on day one of the current financial year and import the history later if needed.
The Swiss legal frame for accounting software
AHV audits and VAT audits follow the same logic: start from the documents, trace to the entries, check consistency. A business in Lengnau (AG) with a clean audit trail sails through these exercises.
The annual accounts (art. 958 CO) consist of the balance sheet, the income statement and the notes; they must be drawn up within six months of the year-end so the general meeting can approve them. A delay here cascades into the tax return and the final social insurance settlements.
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.
For accounting software, a few well-chosen analytical accounts (by activity, by site) beat a forest of sub-accounts nobody ever reads.

QR-bills and friction-free collections
Reminders work best graduated: a neutral first reminder, a firm second, then formal notice — each generated from exact balances, never from memory.
For accounting software, the share of collections matched automatically is a metric worth watching: when it drops, it is almost always a matter of misused references.
Lengnau (AG): what changes, what does not
Sole proprietorship, Sàrl or SA in Lengnau (AG): the AHV contact remains the competent compensation office, and taxes follow the scales of the canton Aargau.
For a business in Lengnau (AG), that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Aargau.
Frequently asked questions
What are the legal obligations for accounting software 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 Lengnau (AG): federal law applies.
How long must records related to accounting software be kept?
Ten years from the end of the financial year concerned (art. 958f CO). Electronic retention is permitted if the integrity and readability of the records are guaranteed — a serious digital archive validly replaces paper binders. A business in Lengnau (AG) can therefore archive fully digitally.
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 Lengnau (AG) as everywhere in Switzerland.
Do you need a fiduciary for accounting software, 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 Lengnau (AG).
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates accounting software for businesses in Lengnau (AG): 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.