# Rule: Account Numbering

A **postable (leaf) account** is exactly **12 characters**, format `CCCCCC-NNNVX`:
- `CCCCCC` = 6-digit chart group, `NNN` = 3-digit counter.
- **`V` (2nd-to-last digit) = currency**: `1` = LBP, `2` = USD.
- **`X` (last digit) = VAT status**: `0` = non-VAT (NVT), `1` = VAT.
- UNO also displays the currency code appended: `711100-00111-01` (`-01`=LBP, `-02`=USD).

A number **without a dash** (`711100`, `711`, `71`, `7`) is a **GROUP / CHART (parent) account — NOT postable.** Never present a group number as "the account"; report the full 12-char leaf.

**Hierarchy = the prefix.** To total a whole group, roll up by leading digits (prefix `7` = all income, `71` = production sales). Tools expose `acclen` / `acnbr_prefix` for this.