
Accounting for engineering firms in Mellikon explained simply
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 Mellikon.
The Swiss legal frame for accounting
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. Accounting sits squarely within this frame, including for companies based in Mellikon.
One simple principle drives accounting: every franc in or out must be explainable by a document, an entry and an account. All of Swiss accounting law fits inside that traceability requirement.
A well-structured SME chart of accounts
The same chart serves three readings: accounting (accuracy), tax (accepted adjustments) and management (margins by activity). Modern software produces all three views without double entry.
In an SME in Mellikon, the chart of accounts is also a delegation tool: clear posting rules let a non-accountant prepare most entries without error.
Outsource accounting or keep it in-house?
The Swiss fiduciary market is dense and governed by professional practice: industry standards, business secrecy, civil liability. Compare offers on three concrete criteria — exact scope (data entry? closing? payroll? VAT?), a named contact person, and the tools used. It prevents year-end misunderstandings.
Three signals say it is time to delegate more: missed deadlines (VAT, AHV), entries running months behind, or an owner spending evenings on receipts instead of the business. Conversely, an SME equipped with modern software can safely take day-to-day entry back in-house.

A Swiss SME's accounting calendar
Three families of deadlines shape the year: federal (VAT within 60 days, salary declaration in January), cantonal (tax return, extensions depending on the canton, including in Mellikon) and internal (closing, general meeting within six months). Mixing them up is the leading cause of delays.
An SME in Mellikon that holds its calendar twelve months straight changes its position: fewer official reminders, easier extensions — and accounting stops being a source of worry.
Mellikon: what changes, what does not
Working with a fiduciary from Mellikon no longer depends on geography: the documents of a business in Mellikon are shared online, while the canton Aargau keeps its own deadlines for the tax return.
For a business in Mellikon, 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 is simplified bookkeeping and who can use it?
Sole proprietorships and partnerships under CHF 500,000 of revenue may limit themselves to recording income, expenses and assets (art. 957 para. 2 CO). Once over the threshold — or upon founding a Sàrl or an SA — full accounts with balance sheet, income statement and notes become mandatory. The CHF 500,000 threshold is assessed the same way in Mellikon.
How long must records related to accounting 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 Mellikon can therefore archive fully digitally.
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 Mellikon too.
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 Mellikon as everywhere in Switzerland.
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Switch to accounting that keeps itself up to date
MyFiducia.ai automates accounting for businesses in Mellikon: AI-read documents, posting suggestions, VAT and exports ready for your fiduciary. Try the platform or browse our other guides.
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