Forecast calculations and engine conventions
The engine calculates results and cash flow month by month from the assumptions entered. Amounts use decimal arithmetic. Each save keeps a version of the assumptions and results.
France profile: new company at the IS
New company to the IS, mainland France, domestic operations, monthly VAT, closing on December 31. Tax result assumed equal to result before IS.
Rules fr-is-ca3-2026.10.11, sources verified on 2026-10-11. Salaries and contributions are assumptions entered, with their sources.
The engine assumptions
- Default constant values. A linear progression maintains the base at month 1, reaches the target at the chosen month and then maintains it. A monthly exception overrides the value for that month only. The months are counted since the start of the activity; settings beyond the chosen duration are retained without being calculated.
- An explicit override in a scenario applies to all months and takes precedence over the monthly field settings. The sales coefficient then applies to quantities excluding subscriptions. For subscriptions: customers of the month = previous customers × (1 − terminations) + new customers; in the first month, the base is the number of customers at start-up.
- Monthly forecast; 30 days of payment are represented by one month lag. Prices and costs excluding taxes.
- VAT: products on delivery/invoice, services upon collection except debit option. Purchases of services deducted from payment except for the supplier's debit option; purchases of goods upon receipt. Monthly declaration and payment the following month, credits retained without automatic reimbursement. No deposit before delivery or service.
- IS: provision adjusted each month on the cumulative result of the financial year, normal rate of 25%, reduced rate of 15% on €42,500 per 12 months only if the conditions are confirmed. Deficits carried forward within the limit of €1 million + 50% of the surplus. Installments for March, June, September, December calculated on previous financial years; first financial year without deposit; sale in May. Excess installments retained as debt, reimbursement and allocation to subsequent installments not simulated. Rules fr-is-ca3-2026.10.11.
- New company to the IS, mainland France, domestic operations, monthly VAT, closing on December 31. Tax result assumed equal to result before IS.
- Excluded cases: Micro-entreprise, IR, rémunération TNS, paie détaillée, franchise de TVA, TVA simplifiée ou trimestrielle, opérations internationales, acomptes clients, déductibilité partielle, crédits d’impôt, réintégrations fiscales, CFE et autres taxes non saisies, exonérations et exercices décalés.
- Acomptes et dispense de 3 000 € : https://bofip.impots.gouv.fr/bofip/3558-PGP.html/identifiant=BOI-IS-DECLA-20-10-20200610
- IS : taux, acomptes et solde : https://www.impots.gouv.fr/professionnel/imposition-des-resultats
- TVA of prestations: https://bofip.impots.gouv.fr/bofip/283-PGP.html/identifiant=BOI-TVA-BASE-20-20-20181107
- Déduction de TVA des achats : https://www.impots.gouv.fr/professionnel/questions/comment-deduire-la-tva-sur-mes-achats
- Premier exercice et acomptes : https://bofip.impots.gouv.fr/bofip/3564-PGP.html/identifiant=BOI-IS-DECLA-20-30-20260121
- Report en avant des déficits : https://bofip.impots.gouv.fr/bofip/2103-PGP.html/identifiant=BOI-IS-DEF-10-30-20130410
- Cotisations et simulation de rémunération : https://mon-entreprise.urssaf.fr/simulateurs/salaire-brut-net
- Employer contributions entered by the user; no legal social regime deduced from an example percentage.
- Stock: initial purchase in the first month, then replacement of consumption from the second month. No initial stock already held.
- Asset acquired and put into service in the first month, straight-line depreciation. Loan disbursed at the beginning; deadlines at the end of the month.
The balance sheet
The engine reconciles assets with financing, debts and cumulative results. Negative cash flow is presented as an overdraft in liabilities. A difference of more than one cent triggers a blocking check.
The current perimeter
The example figures of the six models are fictitious. The profile covers the receipt of benefits, the reduced IS rate under conditions, advance payments and carry-forward losses. It does not produce a tax return.
Micro-enterprise, IR, TNS remuneration, detailed payroll, VAT exemption, simplified or quarterly VAT, international operations, customer deposits, partial deductibility, tax credits, tax reinstatements, CFE and other unentered taxes, exemptions and staggered exercises.
Sources
Deposits and exemption of €3,000
IS: rate, installments and balance
First financial year and installments
Contributions and remuneration simulation
Replace the starting data with your assumptions and verify the rules that apply to your project.