
Bookkeeping for law firms in Würenlos: rules, deadlines, best practice
Between VAT, social contributions and the year-end close, a Swiss SME juggles dozens of deadlines a year. This page focuses on bookkeeping in Würenlos: what the law requires, what can be automated, and when to delegate.
The Swiss legal frame for bookkeeping
Swiss accounting law has been unified in the Code of Obligations since 2013: the same bookkeeping rules (art. 957a CO) and retention rules (art. 958f CO — 10 years for books, vouchers and reports) apply regardless of legal form. Bookkeeping sits squarely within this frame, including for companies based in Würenlos.
Also worth knowing: accounts may be drawn up in the currency most relevant to the business; if that is not the franc, values must additionally be stated in CHF (art. 958d para. 3 CO). Internationally active companies gain books that match their economic reality.
Digitalising bookkeeping: 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 an owner in Würenlos, a dashboard only has value if the data is fresh: automating data entry means, first of all, buying up-to-date information about your own business.
Outsource bookkeeping or keep it in-house?
Responsibility stays with the client: the fiduciary executes with care, but the signed accounts bind the company. Understanding what you sign is not optional.
A business in Würenlos is no longer limited to fiduciaries in its canton: with a shared online platform, collaboration works remotely, documents and entries visible to both sides in real time. The choice widens to all of Switzerland — competence becomes the criterion again, not the postcode.

A Swiss SME's accounting calendar
Extensions exist and can be requested: cantonal deadlines for the tax return, deferral of the VAT filing on a reasoned request. But an extension does not stop interest: on VAT, default interest runs from the ordinary due date even when more time has been granted.
For bookkeeping, year-end is prepared in October: last invoices, investment decisions, provisions to assess — December is too late to act, January is for recording.
Würenlos: what changes, what does not
Sole proprietorship, Sàrl or SA in Würenlos: the AHV contact remains the competent compensation office, and taxes follow the scales of the canton Aargau.
Federal deadlines do not move in Würenlos: VAT within 60 days, salary declaration in January, 10-year record retention — postal code 5436 changes nothing about those rules, only the sender's address.
Frequently asked questions
When is entry in the commercial register mandatory?
A Sàrl and an SA only come into existence with their registration. A sole proprietorship must register from CHF 100,000 of annual revenue; below that, registration stays voluntary but adds credibility and protects the business name. Registration goes through the canton's commercial register office — for Würenlos too.
How much does bookkeeping cost in Würenlos?
It depends on document volume, the number of salaries and VAT complexity — no serious figure can be quoted without examining the file. Two levers cut the bill everywhere: digitised, well-filed receipts and software that prepares entries instead of having them re-keyed.
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 Würenlos, family allowances follow the canton's rates.
How long must records related to bookkeeping 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 Würenlos can therefore archive fully digitally.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates bookkeeping for businesses in Würenlos: 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.