The income tax is calculated by the administration based on the amounts reported by taxpayers who are required to declare their whole income earned during the previous year. But the calculation of income tax takes into account the personal situation of the taxpayer, in particular through the "family quotient" (or units in the household) on the one hand and in the allocation of reductions or tax credits to taxpayers, on the other hand. The family quotient can take into account family responsibilities and, according to them, eases the effects of progressive taxation since the progressive rate is applied to a partial income (the taxable income). This process consists of dividing the taxable income of the household tax into a number of units (or parts) equal to the number of individuals. The progressive scale of tax is then applied to taxable income per share. Finally, this partial tax is multiplied by the number of units to determine the taxable base.