Deduct the business share of your phone costs

Swiss self-employed people can deduct the commercially justified business share of phone costs. Private use remains private. Art. 27 of the Direct Federal Tax Act is the basis; neither a business tariff nor a second device makes every cost automatically deductible.

Which phone expenses can you deduct?

• Subscription and data packages: the documented business share of costs you actually bear.
• The device: the business share under the applicable capitalisation and depreciation rules.
• Roaming: business-related additional charges, supported by evidence such as a client visit; exclude holiday use.
• Apps and cloud services: business use, not personal entertainment.
• Accessories and insurance: where commercially justified, allocating mixed costs.

A deduction is not a refund of the purchase price. Choose a plan that suits your needs, not the largest deduction. Check prices and coverage with providers rather than relying on an undated comparison table.

Do you need a separate business phone?

Not necessarily. A mixed-use phone can suffice. Separate phones or dual SIMs can help distinguish use, but they do not replace evidence. A device called a business phone can still have private use.

For a sole proprietorship, a bill in your personal name can relate to your business. Document ownership, payment and business purpose. An artificial sale of your own subscription to your own sole proprietorship is not a general deduction requirement. Assess the device's tax classification separately.

Calculate a defensible business-use share

There is no universally safe Swiss allowance of 50%, 60%, 70% or 90%. A German simplification rule is not Swiss authority either.

Observe representative use and explain your allocation: call duration, business apps, data consumption and work organisation can provide evidence. Screen time and data volume do not necessarily reflect economic business use equally well. A fixed three-month observation period is not established here as a statutory minimum. Check cantonal requirements and update your share when your activity changes.

Fictional example: Sophie's annual subscription

Sophie pays CHF 45.00 a month, or CHF 540.00 a year. This model assumes an evidenced 60% business share; it does not recommend that percentage for everyone.

At a purely assumed constant marginal income tax rate of 25%, the deduction would reduce income tax by CHF 81.00. This is not a cantonal tax calculation or a promise that a deduction will be accepted. The device and VAT are excluded from this example.

Family plans: allocate twice

First identify the costs attributable to your own line, including demonstrable discounts and add-ons. Then calculate that line's business share. Where the package has no individual line prices, justify your allocation key. Dividing a three-person plan into three equal parts is not automatically correct.

Depreciation for expensive phones

Do not assume a nationwide statutory CHF 1,000 threshold or a compulsory three-year write-off. Capitalisation, asset category and any special cantonal procedures must fit the device and your bookkeeping.

The FTA's A/1995 depreciation guidance gives a normal rate of 40% of book value for data-processing equipment. Rates applied to acquisition cost are generally halved. Confirm whether your device belongs in that category and whether a special cantonal procedure applies before booking it.

Fictional depreciation model: a CHF 1,800.00 acquisition cost depreciated at 40% of declining book value produces CHF 720.00, CHF 432.00 and CHF 259.20 in the first three years. An assumed 70% business share corresponds to CHF 504.00, CHF 302.40 and CHF 181.44. This illustrates arithmetic, not approval of a method for your device. With instalment purchases, separate financing from acquisition: do not deduct both the instalments and full depreciation as expenses.

Check input VAT separately

Registration does not guarantee full input VAT recovery. Eligibility, business use and accounting method matter. Under the net tax rate method, input VAT is not deducted separately. Voluntary registration below the general turnover threshold can also be possible.

Model under the effective VAT method: CHF 75.00 including 8.1% VAT contains CHF 75.00 × 8.1 ÷ 108.1 = about CHF 5.62 VAT. At an assumed 70% eligible business use, that is about CHF 3.93 a month. Use actual invoice figures and avoid rounding every intermediate step.

A device purchased before registration is not automatically excluded from relief: subsequent input tax relief under Art. 32 of the VAT Act may be available subject to conditions. Check remaining value and previous use. See the VAT Act and VAT basics for freelancers.

Your monthly records workflow

1. Save monthly bills, the contract and device purchase invoice.
2. Document business purpose and the allocation key.
3. Date usage evidence and add to it when circumstances change.
4. Record expense and private share separately; assess VAT independently.
5. Maintain an asset register if the device is capitalised.
6. Review allocation, depreciation and exports annually.

Business books and supporting records generally must be retained for ten years from the end of the financial year. Digital retention must secure integrity, readability and availability; a phone photo alone does not establish a compliant archive. See Swiss retention periods and official electronic retention guidance.

Common questions

Can I deduct everything at 90% professional use?

Not as a general Swiss rule. Claiming a high percentage does not turn private costs into business expenses.

Must the percentage stay the same every year?

It should reflect actual use. Consistency helps, but a change in activity can justify a different documented allocation.

Can an app determine my deduction?

You or your fiduciary must check tax allocation and depreciation. This workflow does not assume that Magic Heidi automatically calculates business-use percentages. Check the features and necessary exports before choosing a setup.

Can I add every other tax deduction to this calculation?

Business expenses, personal insurance deductions and pension contributions follow different rules. Adding a maximum Pillar 3a contribution, home office and phone deduction without checking income and eligibility would be misleading. See the deductions checklist.

Sources reviewed on 1 November 2026. Models are fictional and do not replace individual tax advice.