Compound growth, in formulas
Yearly growth does not add up: it compounds. A line's monthly detail grows the value entered from one financial year to the next, each year starting from the previous one, and saves the resulting months.
Notation
- the value entered on the line: the amount, the quantity or the percentage, depending on the calculation method
- the growth entered for financial year , in %; an empty box counts as 0%
- the value of each month of financial year
- the total excl. VAT of financial year
The growth
(1): financial year 1 keeps the entry; each following year starts from the previous one. Rounding is to the cent for an amount; a quantity or a percentage keeps its decimals. With quantity × price, the quantity grows and the price stays as entered; with a percentage of revenue, the percentage grows. A month changed by hand is an exception: it is never used as a base, and the screen asks whether to keep it when its calculation changes. VAT follows each month's amount excl. VAT.
Numerical application · Boulangerie Dupont, 2027-2029
The running example's sales, €18,000.00 excl. VAT per month in 2027, with 3% for financial year 2 and 3% for financial year 3 (three 12-month financial years).
Financial year 3's growth applies to €18,540.00, not to the 2027 entry: two successive growths of 3% give more than their sum.
The journal entry
| Side | Account | Description | Amount |
|---|---|---|---|
| Debit | 550000 | Credit institutions — Current accounts | 19,652.40 |
| Credit | 700000 | Sales and services | 18,540.00 |
| Credit | 451000 | VAT payable | 1,112.40 |
The engine does not calculate growth: it reads the amounts the monthly detail saved, month by month, and writes them like any sale. The running example's sales have no payment term: they go through the bank in the month of the invoice; with a term, through trade receivables (see Cash and payment terms, in formulas).
Try it yourself
Change the growth: formulas (1) and (2) are recalculated
Three 12-month financial years (2027 to 2029), sales at 6% VAT. The block rolls out a trial line with the screen's function (deroulerAvecCroissance) and reads the months it returns.
Source
Application rule (workshop decisions D3 and D4, approved on 08/10/2026): compound growth on the value entered, empty box = 0%, month by hand = exception (src/lib/croissance-ligne.ts). No accounting rule: growth is the user's assumption.