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Italian withholding certificate (Certificazione unica, CU)

Anyone who, acting as withholding agent (sostituto d'imposta), paid amounts subject to withholding in 2025, such as a professional's fee, certifies them with the Certificazione unica 2026 (CU). Delivery to the recipient, on the « sintetico » form, and online transmission to the Agenzia delle Entrate, on the « ordinario » form, are both due by 16 March 2026; CUs containing only income from habitual self-employment or non-occasional commissions are sent to the Agenzia by 30 April 2026.

Up to date for 2026 — verified on September 24, 2026Official procedure, no printed formGuide: about 30 min

This content is part of the path: Self-employed professional with withholding tax· Step 9 of 11· Next step: Italian income tax return: Redditi Persone fisiche form

This content is part of the path: Hiring your first employee· Step 8 of 11· Next step: Italian 770/2026 form: the withholding agents' return

Deadlines

16 March 2026
Delivery of the sintetico form to the recipient and online transmission of the ordinario form to the Agenzia
30 April 2026
Transmission to the Agenzia of CUs containing only income from a habitual art or profession or non-occasional commissions (commission, agency, brokerage, sales representation, business introduction)
2 November 2026
Transmission of CUs containing only exempt income or income that cannot be declared through the pre-filled return, by the deadline of the withholding agents' return (31 October, a Saturday)

Documents to prepare

  • The list of amounts paid during the year to each recipient, with their personal details and tax code
  • The tax withheld and the F24 forms used to pay it over
  • Any social-security contributions and deductions applied
  • The Agenzia's compilation software and control procedure, and access to the online services or an authorised intermediary
See the procedure on the official site

No form is attached to this procedure: the link leads to the official page that describes it.

What this page gives you

The guide above and the link to the official site. ActioFin does not produce any document for this page: whatever you fill in or file is done on the official medium.

Who this applies to

  • Withholding agents who, in tax year 2025, paid employment and similar income, self-employment income, commissions and miscellaneous income, or consideration under short-term rental contracts
  • In particular the professional, company or business that paid a professional's invoice and withheld tax on account: the withholding must be certified by whoever made it
  • The recipient of the amounts receives the sintetico form; the Agenzia receives the ordinario form

Worked example

Studio Ferri, architects in Turin, certifies a surveyor's fee

In 2025 Studio Ferri paid Paolo Greco, an Italian-resident surveyor who practises his profession habitually, fees of 3,000 euros, withholding 600 euros on account as computed by the ritenuta-acconto-professionisti calculator and paid over with the F24. By 16 March 2026 it gives Paolo the sintetico CU showing the amount paid and the tax withheld. Because his CU contains only habitual professional self-employment income, the studio may send the ordinario form to the Agenzia by 30 April 2026 rather than by 16 March.

How to fill it in, step by step

  1. Identify every recipient to whom you paid amounts subject to withholding during the year, starting from your payments and the F24 payments of the withheld tax.
  2. For each one, total the amounts paid, the tax withheld, the deductions applied and the social-security contributions.
  3. Complete the sintetico form and give it to the recipient by 16 March.
  4. Complete the ordinario form with the Agenzia's compilation software and check it with the control procedure.
  5. Send it online to the Agenzia by 16 March, or by 30 April if the certification contains only habitual self-employment income or non-occasional commissions.

Good to know

  • The « sintetico » form is the one given to the recipient; the « ordinario » form is the one sent to the Agenzia: they are two separate documents.
  • The certification must show the total amounts paid, the tax withheld, the deductions and the contributions; it may carry optional data such as the professional contribution or VAT.
  • The longer 30 April deadline applies only to transmission to the Agenzia: delivery to the recipient stays at 16 March.
  • The CU 2026 covers tax year 2025: the form carries the year in which it is filed, not the year of the payments.
  • The withholding to be certified is computed by the ritenuta-acconto-professionisti calculator; its payment is covered by the guide on paying withholding tax on self-employment income.

Common mistakes

  • Giving the CU to the professional in April because transmission to the Agenzia is due on 30 April: delivery is due on 16 March.
  • Applying the 30 April deadline to a CU that also contains employment or similar income.
  • Certifying the net amount paid instead of the total amount paid and the tax withheld.
  • Confusing the year of the CU with the tax year: the CU 2026 certifies amounts paid in 2025.

Frequently asked questions

When must the Certificazione unica 2026 be delivered?

By 16 March 2026, on the sintetico form, to the recipient of the amounts. By the same date it must be sent to the Agenzia on the ordinario form, except for the longer deadlines set for some certifications.

I paid a professional: when do I send the CU?

If the certification contains only income from a habitual art or profession, by 30 April 2026. Delivery to the professional is still due by 16 March.

What must the withholding certificate contain?

The total amounts and values paid, the tax withheld, the tax deductions applied and the social-security contributions; optionally other data such as the professional contribution or VAT.

Which CUs may be sent as late as November?

Those containing only exempt income or income that cannot be declared through the pre-filled return: by the deadline of the withholding agents' return, 2 November 2026.

Go further

Compute the related amounts

Understand this form: the related course

Related forms

Official sources

Read in Italian

Guide and document provided for information purposes only; they do not constitute personalised legal or tax advice. Check the recipient organisation's requirements and consult a professional if needed.