自動化・効率化ならKTパソコンスクール

'個人事業主の所得税を計算する関数

Function IncomeTax(profit As Currency, Optional other As Currency) As Currency

    Const aoiro As Currency = 650000    '青色申告控除

    Const kisokoujo As Currency = 380000    '基礎控除

    Dim kazeishotoku As Currency    '課税所得

    Dim temp As Currency    '一時的に数値を収納する変数

    

    '課税所得の計算（profitは収入 - 経費、otherはその他控除がある場合のオプションの引数）

    kazeishotoku = profit - aoiro - kisokoujo - other

    

    '課税所得が

    Select Case kazeishotoku

        '195万円以下なら

        Case Is <= 1950000

            temp = kazeishotoku * 0.05

            '0より小さければ、0にする

            If temp < 0 Then

                IncomeTax = 0

            Else

                '1000円未満は切り捨て

                IncomeTax = Application.RoundDown(temp, -3)

            End If

        '330万円以下なら

        Case Is <= 3300000

            temp = kazeishotoku * 0.1 - 97500

            IncomeTax = Application.RoundDown(temp, -3)

        '695万円以下なら

        Case Is <= 6950000

            temp = kazeishotoku * 0.2 - 427500

            IncomeTax = Application.RoundDown(temp, -3)

        '900万円以下なら

        Case Is <= 9000000

            temp = kazeishotoku * 0.23 - 636000

            IncomeTax = Application.RoundDown(temp, -3)

        '1800万円以下なら

        Case Is <= 18000000

            temp = kazeishotoku * 0.33 - 1536000

            IncomeTax = Application.RoundDown(temp, -3)

        '4000万円以下なら

        Case Is <= 40000000

            temp = kazeishotoku * 0.4 - 2796000

            IncomeTax = Application.RoundDown(temp, -3)

        '4000万円超なら

        Case Else

            temp = kazeishotoku * 0.45 - 4796000

            IncomeTax = Application.RoundDown(temp, -3)

    End Select

End Function