Salary plus an ordinary VAT-registered activity: how they add up for IRPEF

Davide earns 40,000 € as an employee and, outside the flat-rate scheme, bills another 12,000 € as a consultant. His employer withholds IRPEF every month and each client keeps 20 %. Everything seems paid. Then he finds that the extra tax on those 12,000 € tops 5,000 €, and that 2,628.10 € is still due by F24 before July.

One single total income

Outside the flat-rate scheme there is no separate tax on the VAT-registered activity. Article 8 of the TUIR says total income is found by adding up the income of every category that makes it up. Salary and self-employment income end up in the same figure.

For self-employment, income is fees received minus the activity's costs. Someone billing 12,000 euros with 2,000 euros of related costs adds 10,000 euros to total income. Keeping track of costs is therefore not an accounting nicety: it lowers the tax directly.

Adding the two has a consequence the flat-rate scheme avoids. Self-employment income gets no rate of its own; it sits on top of the salary, in the higher brackets the salary has left free. That is where the real cost of the second job is decided.

The bracket where the extra income lands

The text of TUIR article 11 in force for 2026 sets three rates: 23 % up to 28,000 euros, 33 % above 28,000 and up to 50,000, 43 % above 50,000. The salary fills the lower brackets first; self-employment income is stacked on top.

For an employee on 40,000 euros, the middle bracket still has 10,000 euros of room. The first 10,000 euros of self-employment income are taxed at 33 %, anything beyond at 43 %. Someone on a 20,000-euro salary, by contrast, sees the first 8,000 euros of self-employment income taxed at 23 %.

These figures leave out the regional and municipal surcharges, which apply to the same income and raise the burden further. To estimate the full load, add them using the rates of your own region and municipality, which differ from place to place.

Two credits that do not add up

TUIR article 13 grants one credit for employment income, in paragraph 1, and another for self-employment income, in paragraph 5. Someone with both might expect to add them. The statute rules that out: the paragraph 5 credit is declared not combinable with the paragraph 1 credit.

Both are computed on total income, not on the income that gives rise to them. Every euro of self-employment income added to the salary therefore shrinks the employment credit, on top of being taxed at the marginal rate. It is a second cost, less visible than the first.

Between 28,000 and 50,000 euros the credit equals 1,910 euros times the ratio between the distance to 50,000 euros and 22,000 euros. The ratio is taken to its first four decimal places, without rounding. Above 50,000 euros of total income no credit is due at all.

In that band every extra 1,000 euros of income removes about 87 euros of credit, that is 1,910 divided by 22. Added to the 33 % rate, the effective marginal take exceeds 41 %, before any surcharges. That is the figure to keep in mind when weighing up an assignment.

Who withholds what

During the year two parties withhold tax on the taxpayer's behalf, and neither sees the whole picture. The employer computes withholding on the salary as though it were the only income, applying the full credit that goes with it. It knows nothing about the VAT number.

Clients acting as withholding agents keep 20 % of fees on account. It is a flat percentage that ignores the bracket where the fee will land. For anyone on a mid-range or high salary, 20 % almost always falls short of the actual tax.

The result is a built-in gap. The year's withholding covers tax on the salary with the full credit plus 20 % of fees. The real tax hits fees at 33 or 43 % and cuts the credit. The shortfall shows up in the return, all at once.

Form 730 is no longer enough

The Agency's 730/2026 page accepts self-employment income only where no VAT number is required. VAT-registered taxpayers must use the Redditi Persone fisiche return, which the same Agency makes compulsory for anyone with business or self-employment income.

The Redditi return reports both the salary, using the employer's Certificazione Unica, and the activity's income, with the withholding certified by clients. The final calculation brings everything together: tax on total income, the credit due, and the tax already withheld.

So in spring several certificates arrive: one from the employer for the salary and one from each client that withheld tax. Keep them in a single folder and check every figure against the invoices you issued. Withholding that is uncertified, or wrongly certified, may never be credited to you.

People used to the pre-filled 730 also need a new calendar. The Redditi return has its own deadlines, different from the 730's, and payment no longer goes through the payslip. Many employees with a VAT number hand the return to a professional or an assistance centre precisely so as not to miss them.

One thing stays simple: the salary is declared exactly as before, copying the Certificazione Unica figures. Nothing about the employment income is recalculated. The new work concerns only the VAT-registered activity and the recalculation of total tax, which the filing software performs from the data entered.

Balance, advances and F24

With form 730 and a withholding agent, any tax due was deducted from the salary from July. With Redditi PF it is not: the Agency states that the balance and any first advance instalment are paid by F24 by 30 June, or within the following 30 days with a 0.40 % surcharge.

The first year with a VAT number often brings a double surprise. Besides the balance for the year just closed, an advance is due for the current year, based on the tax declared after credits and withholding. If it exceeds 257.52 euros it is paid in two instalments, in June and November.

For most taxpayers the first instalment is 40 % and the second 60 %. For those subject to the synthetic reliability indices and for flat-rate taxpayers the page provides two equal instalments. If you are unsure which applies to you, check with your adviser before June.

The advance is not extra tax: it prepays the current year's tax and is credited in the next return. But it strains first-year cash, when two years' tax fall due together. Expecting lower fees, you may pay a smaller advance based on the tax you foresee, at your own risk.

Costs, the lever that remains

Under the ordinary regime, self-employment income is fees minus costs. Every related, documented cost lowers the income stacked on the salary, and so the tax at the marginal rate. For someone in the 33 % band, a 1,000-euro cost saves 330 euros of IRPEF, plus credit that is no longer lost.

That lever does not exist under the flat-rate scheme, where income is computed with a fixed coefficient and actual costs are ignored. It is one reason why, on equal fees, an employee under the ordinary regime with heavy costs may pay less than expected, and one with no costs a good deal more.

Related means linked to the activity; documented means backed by an invoice or receipt in your name. A computer used for both freelance work and leisure calls for caution over the share deducted. The detailed rules on deductible costs belong to a separate course.

Setting money aside during the year

The simplest way to avoid the shock is to set money aside with every payment. Take the fee net of costs, estimate the effective marginal take for your band, subtract the withholding already suffered, and move the difference to a separate account. It gets emptied in June.

For anyone with total income between 28,000 and 50,000 euros, the effective marginal IRPEF take exceeds 41 %. With 20 % already withheld, more than a fifth of each fee still needs setting aside, before surcharges. Above 50,000 euros you need to put away even more.

An even simpler method is to estimate the expected balance at the start of the year from forecast fees and set aside a twelfth of it each month. Halfway through the year, redo the estimate with actual receipts. The principle holds: put aside during the year what the return will demand anyway.