odoo/odoo · error · UserError

You cannot reduce the number of decimal places of a currency

Error message

You cannot reduce the number of decimal places of a currency which has already been used to make accounting entries.

What it means

Raised by res.currency.write (addons/account/models/res_currency.py:31) when you increase the rounding value (or set it to 0) of a currency that already has accounting entries. A larger rounding factor means fewer decimal places, which would contradict amounts already computed and stored on move lines, so Odoo refuses the change for used currencies.

Source

Thrown at addons/account/models/res_currency.py:31

        return ','.join(self.env.companies.mapped('account_fiscal_country_id.code'))

    display_rounding_warning = fields.Boolean(string="Display Rounding Warning", compute='_compute_display_rounding_warning',
        help="The warning informs a rounding factor change might be dangerous on res.currency's form view.")
    fiscal_country_codes = fields.Char(store=False, default=_get_fiscal_country_codes)

    @api.depends('rounding')
    def _compute_display_rounding_warning(self):
        for record in self:
            record.display_rounding_warning = (
                record._origin.id and record._origin.rounding != record.rounding
            )

    def write(self, vals):
        if 'rounding' in vals:
            rounding_val = vals['rounding']
            for record in self:
                if (rounding_val > record.rounding or rounding_val == 0) and record._has_accounting_entries():
                    raise UserError(_("You cannot reduce the number of decimal places of a currency which has already been used to make accounting entries."))

        return super(ResCurrency, self).write(vals)

    def _has_accounting_entries(self):
        """ Returns True iff this currency has been used to generate (hence, round)
        some move lines (either as their foreign currency, or as the main currency).
        """
        self.ensure_one()
        return bool(self.env['account.move.line'].sudo().search_count(['|', ('currency_id', '=', self.id), ('company_currency_id', '=', self.id)]))

    def _get_simple_currency_table(self, companies) -> SQL:
        """ Helper creating the currency table and returning its definition for basic cases of Odoo reports needing to convert amounts using only the
        current rates, in a single period.
        """
        if self._check_currency_table_monocurrency(companies):
            return self._get_monocurrency_currency_table_sql(companies)

        self._create_currency_table(companies, [('period', None, fields.Date.today())])

View on GitHub (pinned to 1e661df964)

Solutions

1. Keep the historical currency untouched and create a new currency record with the desired rounding, then use it going forward.
2. Only decrease rounding (more precision) on a used currency — that direction is permitted.
3. On an empty/test database, remove the accounting entries (or use a fresh DB) and then change rounding.

Example fix

# before
currency.write({'rounding': 1.0})  # UserError: currency already used

# after (new currency for future use)
new_cur = currency.copy({'name': currency.name + ' (2dp→0dp)', 'rounding': 1.0})

def can_set_rounding(currency, new_rounding):
    if new_rounding > currency.rounding or new_rounding == 0:
        return not currency._has_accounting_entries()
    return True

When it happens

Trigger: write({'rounding': X}) where X > record.rounding (e.g. going from 0.01 to 0.05/1.0) or X == 0, on a currency referenced by any account.move.line.currency_id or company_currency_id (_has_accounting_entries does a sudoed search_count). Decreasing rounding (more decimals) is allowed.

Common situations: Fixing a misconfigured currency (e.g. rounding set to 0.01 when it should be 1 for a zero-decimal currency like JPY) after transactions exist; data imports or demo-data corrections on currencies already used by invoices; enabling a new decimal convention on a live database.

Related errors

• The foreign currency must be different than the journal one:
• You can't provide an amount in foreign currency without spec
• You can't provide a foreign currency without specifying an a
• No journal could be found in company %(company_name)s for an
• Cannot find a chart of accounts for this company, You should

AI-assisted analysis of odoo/odoo@1e661df964 (2026-08-15). Data as JSON: /api/errors/8febe56dd9d807d9. Report an issue: GitHub.