サラリーマン定額減税　サクッと見える化

■Description
The target audience is ordinary office workers who do not need to file a tax return, who are probably the "silent majority."

Input into the frame with a green background color and output the predicted value by clicking "Start calculation". Both the income tax amount for 2020 and the special collection tax amount for 2020 have been determined, so please enter them. The initial value of "Number of months of bonus payment" is the value from information published by the Japan Business Federation (2021 final survey). The "forecast income tax amount for FY2020" has been increased by 3% from the initial value for FY2020.

There is no basis for the 3% rate, and although you will benefit from higher wages, your social insurance premiums will increase...I wonder if this will be enough after deducting it? It's just a sensory value. If you foresee a major change in the number of dependents or the amount of deductions, try calculating them manually.

■Calculation specifications
The contents are simply divided and calculated.

Resident tax is distributed in the usual manner: before tax reduction = 12 months pro rata, after tax reduction = 11 months pro rata, and fractions are adjusted in the first month.
For income tax, the estimated income tax amount for FY2020 is divided into ``12 months + predicted number of bonus months'', and the number of bonus months is weighted towards June and December, and the fraction is adjusted in December.
If the bonus months forecast is set to 0, it will be calculated using equal distribution.
The adjustment amount is calculated by rounding up the tax amount that could not be reduced to the nearest 10,000 yen.