Each income source (salary, pension, capital, self-employed) follows its own rules. The total you see sums all four.

• Private-sector employee: employee contributions ex-CSG ≈ 12.5% of gross + CSG/CRDS ≈ 9.7% (URSSAF 2024) → gross/net ratio ≈ 1.29. Employer contributions (~42% of gross) are flagged separately — they're part of the employer cost, not your net.
• Pension: CSG rate variable (0% / 3.8% / 6.6% / 8.3%) by reference taxable income (DGFiP 2025 schedule). The default profile uses the weighted-average rate.
• Capital income: 30% flat tax by default (12.8% income tax + 17.2% social levies), CGI art. 200 A. Progressive-bracket option not simulated.
• Self-employed (micro-entrepreneur): URSSAF rates by activity — sales (~12.3%), services BIC (~21.2%), services BNC (~21.1%). Optional discharge income tax not applied by default.
• VAT: estimated at 10.4% of disposable income — weighted-average rate 12.2% (INSEE T_TES, real basket per decile) × propensity to consume 85% (INSEE household accounts). Smooths decile disparities.
• Income tax: 2025 5-bracket schedule + family quotient with per-half-share cap. Computed on net taxable income inferred from the displayed net.
• Property tax (commune proxy): local taxes per inhabitant × 0.4 (TF + secondary-residence TH share) × 2.2 (average household size). Approximation for average owner-occupiers.

Sources : URSSAF · CGI art. 200 A · DGFiP barème 2025

To stay readable, the calculator ignores several flows that can materially shift your real total — in either direction.

• Tax reductions and credits: R&D credit (CIR), childcare, donations, actual expenses, home employment. Can lower effective income tax by hundreds to thousands of euros.
• Consolidated income tax on multi-source RFR: if you combine salary + capital + self-employed, real income tax is computed on the sum (RFR), not source by source. The personal estimate here adds four separate income taxes — acceptable approximation for simple profiles, to reconsider for large multi-source aggregates.
• Social benefits received (RSA, housing aid, disability allowance, family allowances, employment bonus…): not subtracted from the total. The calculator shows what you pay, not your net balance with the state.
• Cross-tab nature × function at local-government level: OFGL publishes either nature or function, not the fine cross by commune. Local drilldown stops at city block / department / region.

All values come from official public sources — rate schedules for the personal calculation, national accounts for the Social security / State / Local breakdown.

• URSSAF — official rates and schedules for social contributions.
• CGI — income tax schedule, flat tax, family quotient caps.
• INSEE — GDP, population, household accounts, T_TES (effective VAT rates).
• Eurostat gov_10a_main — general government breakdown by sub-sector S1311 / S1313 / S1314.
• PLF 2025 — 33 missions × programmes × actions (data.economie.gouv.fr).
• PLFSS 2025 — ONDAM + Social security branches (Annex 5).
• OFGL 2025 — local-government finances by function (cities, departments, regions).
• DREES Comptes santé — health accounts, breakdown ambulatory / hospital / drugs.

General government (APU) is split into three accounting sub-sectors. Daily Bread uses a CAUSAL view: each tax goes to its actual legal recipient, not a proportional split. (For the proportional Eurostat view, see Budget Explorer /fr/national/budget.)

• S1311 Central state + ODAC ≈ €676 bn/yr — ministries, agencies, debt service. You contribute via {b}your income tax{/b} + {b}45% of your VAT{/b} (State share, PLF V&M).
• S1313 Local government ≈ €334 bn/yr — cities, EPCIs, departments, regions. You contribute via {b}your property tax{/b} (if homeowner) + {b}24% of your VAT{/b} (housing-tax/CVAE compensation).
• S1314 Social security ≈ €798 bn/yr — health (CNAM), pensions (CNAV), family (CAF), unemployment (Unédic), workplace (AT-MP). You contribute via {b}your social contributions{/b} + {b}CSG/CRDS{/b} + {b}31% of your VAT{/b} (allocated VAT) + {b}capital social levies (17.2%){/b}.

Causal vs proportional view: Daily Bread maps each euro of tax to its actual recipient (contributions → Social Security, income tax → State, VAT → 3 sub-sectors per PLF allocation). Budget Explorer (/fr/national/budget) keeps the Eurostat S13 proportional view (44/37/18) showing each sub-sector's share of total public SPENDING. Both are useful: causal for « where does MY contribution go », proportional for « how is national public spending distributed ».

The exact French tax computation goes through OpenFisca, the official simulation engine maintained by DINUM/Etalab — source code aligned with the current finance law, updated at each PLF.

Daily Bread is a simplified MVP, designed to stay accessible without a tax-portal login and without entering a detailed RFR. Goal: a readable order of magnitude plus a deep drilldown — not a replacement for impots.gouv.fr.

For the salaried profile, a “Refine with OpenFisca” button in the editable hero runs the exact calculation via the public API — useful for comparing the MVP estimate to the official value.