If you have looked into flat-rate or simplified tax regimes, you have met a strange-sounding term: the profitability coefficient. It is one of the most important numbers in your tax calculation, yet it is rarely explained clearly. This guide covers what it is, how Italy, Portugal and France use it, how to find the right one for your activity, and what it costs you in cash across a full tax year.
The Core Idea, With Numbers
A profitability coefficient is a fixed percentage that a tax authority applies to your revenue to estimate your taxable profit, instead of making you calculate profit from real expenses. The state says: "For your type of work, we assume this percentage of turnover is profit, and we tax you on that."
This is the defining feature of flat-rate regimes. Under normal accounting, taxable profit equals revenue minus documented costs. Under a coefficient regime, taxable profit equals revenue multiplied by the coefficient. You do not deduct real expenses, because they are assumed to be baked into the coefficient.
Imagine you are a consultant invoicing 50,000 a year, with a profitability coefficient of 78%. Your taxable income is not 50,000, and it is not 50,000 minus your laptop and software. It is:
50,000 x 78% = 39,000 taxable income.
The regime's tax rate is then applied to that 39,000, not to the full 50,000. The remaining 22% (11,000) is treated as assumed business costs, deducted automatically whether or not you spent that much. This is why coefficient regimes suit people with low real expenses: a generous automatic deduction, and no shoebox of receipts.
Why Governments Use Coefficients
Coefficients simplify life for small businesses and for the tax authority at once. Real profit calculation means tracking every receipt, depreciation schedule and cost category, a heavy burden for a solo freelancer. A standard percentage per activity removes expense accounting and reduces disputes over what is deductible.
The trade-off is fairness in edge cases. If your real costs exceed the assumed percentage you lose out, because you cannot deduct the difference. If they are lower, you win. The coefficient is an average, so it never fits every business perfectly.
Italy's Forfettario: Coefficients by ATECO Code
Italy's regime forfettario is the best-known example. Every activity has an ATECO code, and each code maps to a coefficient set out in Annex 4 of Law 190/2014. Your ATECO code determines your coefficient, which determines your taxable base. The regime then applies a substitute tax of 15%, reduced to 5% for the first five years if you qualify as a genuinely new activity, and the revenue ceiling is 85,000 euro. The official rules are on the Agenzia delle Entrate site. Here are the main coefficients by activity group:
| Activity type (Italy forfettario) | Profitability coefficient | Assumed costs |
|---|---|---|
| Professionals, scientific, technical, health, education, financial services | 78% | 22% |
| Other activities (includes ATECO 62-63, software and IT) | 67% | 33% |
| Construction and real estate | 86% | 14% |
| Commercial intermediaries and agents | 62% | 38% |
| Food and accommodation services | 40% | 60% |
| Retail and wholesale trade | 40% | 60% |
Notice the logic. A consultant has low costs, so 78% of turnover is assumed to be profit. A restaurant or shop has heavy costs (ingredients, stock), so only 40% is. Software and IT under ATECO 62 sits at 67%, a 33% assumed cost allowance. Model the full calculation, substitute tax and INPS included, with our Italy flat-rate tax calculator.
From Coefficient to Cash: a Full Worked Example
It is easy to confuse the coefficient with the tax rate, but they are two separate levers applied in sequence. The coefficient converts revenue into taxable income; the flat rate is then applied to that income. For an Italian startup professional, a 78% coefficient plus the 5% substitute tax gives an effective income-tax rate of just 3.9% of turnover, before social contributions.
Contributions are where the real money is. Complete example: an IT consultant under ATECO 62.01, invoicing 60,000 euro, in the fifth year of activity (still on the 5% rate), enrolled in the INPS Gestione Separata.
- Gross flat-rate income: 60,000 x 67% = 40,200 euro.
- INPS Gestione Separata contributions at the 2026 rate of 26.07% for professionals with no other pension scheme (INPS Circular 8/2026): 40,200 x 26.07% = 10,480 euro.
- Contributions actually paid during the year are deducted from the flat-rate income: 40,200 - 10,480 = 29,720 euro taxable base.
- Substitute tax at 5%: 1,486 euro. (At the standard 15% rate it would be 4,458 euro.)
Total cost: about 11,966 euro on 60,000 euro of invoices, roughly 20% of turnover, of which the tax itself is only 2.5%. The key insight: the coefficient drives the tax, but it also drives the pension contributions, and the contributions are the bigger number. Artisans and traders instead pay the INPS artisan or trader fund: a fixed 2026 minimum of 4,521.36 euro (artisans) or 4,611.64 euro (traders), plus 24% or 24.48% on flat-rate income above the 18,808 euro minimum, with an optional 35% reduction to request by 28 February.
Portugal's Simplified Regime: Coefficients Plus an Expense Test
Portugal's regime simplificado uses the same principle with a different set of coefficients, applied to your IRS (personal income tax). Instead of ATECO codes, Portugal groups activities broadly under Article 31 of the IRS Code. The coefficient sets the taxable share of gross income, and Portugal's progressive IRS rates (nine brackets in 2026, topping out at 48%) apply to that share. The regime is open while Category B income stays at or below 200,000 euro a year.
| Income type (Portugal simplified regime, Art. 31 CIRS) | Coefficient | Taxable share |
|---|---|---|
| Sale of goods and products | 0.15 | 15% |
| Hotel, restaurant and beverage activities | 0.15 | 15% |
| Listed professional services (Article 151 list) | 0.75 | 75% |
| Other services not on the list | 0.35 | 35% |
| Local accommodation, house or flat, in a containment area | 0.50 | 50% |
| Intellectual or industrial property, capital, property income | 0.95 | 95% |
| Operating subsidies and other Category B income | 0.10 | 10% |
The official text is on the Portal das Finanças page for Article 31. The catch: for the 0.75 and 0.35 coefficients, part of the assumed cost allowance must actually be justified. You must document expenses equal to 15% of gross income, and anything you cannot document is added back to taxable income. Worked example, a freelancer on the 0.75 coefficient invoicing 45,000 euro:
- Taxable base from the coefficient: 45,000 x 0.75 = 33,750 euro.
- Expenses that must be justified: 15% of 45,000 = 6,750 euro.
- Automatic allowance, no paperwork needed: 4,462.15 euro (the Category A specific deduction), plus mandatory social contributions above that amount, plus staff costs, rent and other business expenses.
- With 6,741 euro of social security paid (21.4% on 70% of service income, the 2026 self-employed rule per Segurança Social), the justified total reaches 6,741 euro and only 9 euro is added back to taxable income.
Run your own numbers with the Portugal simplified regime calculator. Note also the start-up relief: the coefficient is cut by 50% in the first year of activity and by 25% in the second, a large discount in the two years you can least afford tax.
The Same Idea in France and Elsewhere
France runs the identical mechanism under another name. The micro-entreprise regime applies an abattement forfaitaire, a flat deduction, to turnover. Italy states the profitable share, France states the deducted share, and the arithmetic is the same.
| France micro-entreprise category | Flat deduction (abattement) | Effective coefficient (taxable share) |
|---|---|---|
| Sale of goods (micro-BIC) | 71% | 29% |
| Services (micro-BIC) | 50% | 50% |
| Liberal professions (micro-BNC) | 34% | 66% |
Details are published by service-public.fr. The pattern repeats: Hungary's flat-rate personal income tax and Spain's módulos also use presumed cost ratios. Our tax comparison tool puts these systems side by side, and the glossary defines the local terms.
Deadlines, Payments and What to Set Aside
A coefficient regime saves bookkeeping, not cash-flow shocks: nothing is withheld at source. You invoice gross, you are paid gross, and the tax authority collects much later.
| Country | Main payment dates | What is due |
|---|---|---|
| Italy (forfettario) | 30 June (often extended to 20 July), then 30 November | Prior-year balance plus first advance (40%), then second advance (60%). Paid by F24, tax code 1790 |
| Italy (INPS) | Quarterly (artisans and traders); with the tax deadlines for Gestione Separata | Fixed minimum contributions plus the rate on income above the minimum |
| Portugal (IRS) | Return filed 1 April to 30 June; payment by 31 August | IRS on the coefficient-based income |
| Portugal (Segurança Social) | Quarterly declaration in January, April, July, October; paid by the 20th monthly | 21.4% on 70% of service income |
The advance-payment system catches people out. In Italy, the year you settle your first full bill you also prepay the next year, so one June deadline can be nearly double what you expected. The rule: open a separate account and move a fixed share of every invoice into it the day it lands. For an Italian professional on the 78% coefficient, the 15% rate and Gestione Separata, set aside 32% to 35%; on the 5% start-up rate, 25% is usually enough. Late payment carries interest plus a penalty that falls sharply if you self-correct quickly (ravvedimento operoso).
The First Year, Leaving the Regime, and Who Is Excluded
The first year is not like the others. In Italy you make no advance payment in year one, because advances are based on the previous year's tax, which was zero. Cash flow looks wonderful, then the next June you pay a full balance and an advance together. In Portugal the coefficient is halved in year one and cut by a quarter in year two, so your tax jumps in year three even if invoicing is flat. Plan for that step-up.
Leaving matters too. In Italy, if revenue exceeds 85,000 euro but stays under 100,000, you finish the year in the forfettario and move to ordinary rules from 1 January. If you cross 100,000 euro the regime ends immediately: VAT applies to invoices issued from that point and the whole year is taxed under ordinary IRPEF. Watch that cliff edge in November and December. In Portugal, exceeding 200,000 euro of Category B income moves you to organised accounting the following year (immediately if you exceed it by over 25%).
These regimes are for individuals, not companies: an Italian SRL or a Portuguese Lda pays corporate tax on real accounting profit and never touches a coefficient. Italy also excludes anyone with more than 35,000 euro of employment or pension income in the previous year (unless the job ended), anyone controlling a company in the same field, anyone invoicing mainly a current or recent employer, and most non-residents.
Common Mistakes That Cost Real Money
Wrong activity code. In Italy the coefficient follows the ATECO code chosen when you open your VAT position, and a wrong code can move your tax base by tens of percent. With genuinely mixed activities (you consult and also sell products), you must split revenue across codes and apply each coefficient to its portion, not the friendliest coefficient to everything.
Wrong regime for your cost structure. A professional on a 78% coefficient who really spends 40% of turnover on subcontractors and equipment is taxed as if most of those costs did not exist. Ordinary accounting with real deductions can then produce a lower bill despite a higher headline rate. The test: compare your real cost ratio to the assumed allowance. Below it, the regime wins; above it, it loses, and the gap compounds yearly.
Assuming no records are needed. You still number and keep invoices, keep proof of contributions paid, retain documents for the statutory period (ten years in Italy), and in Portugal you need receipts to pass the 15% test. "No accounting" means no profit-and-loss computation, not no paperwork.
Key Takeaways
A profitability coefficient is the government's assumption about how much of your revenue is profit. Italy's forfettario uses ATECO coefficients from 40% to 86%, a 5% or 15% substitute tax and an 85,000 euro ceiling. Portugal's simplified regime uses coefficients from 0.10 to 0.95, a 200,000 euro ceiling and a 15% expense test. France reaches the same result with 34%, 50% and 71% flat deductions. In every case the coefficient sets your taxable base, the tax rate applies on top, and contributions are usually calculated on the same coefficient-based income. If your real costs are low these regimes are hard to beat, but the choice deserves a calculation, not an assumption.
General information, not tax advice. The rates and thresholds cited are those in force for 2026 and change with each annual budget law. Confirm your position with a qualified accountant.