حاسبة ضريبة المبيعات

مبادئ الحساب والصيغة الرياضية

Sales Tax Calculation Formulas:

1. Add Tax to Price:
   Tax Amount = Price × Tax Rate ÷ 100
   Total Price = Price + Tax Amount

2. Extract Tax from Price:
   If price includes tax:
     Price Before Tax = Price ÷ (1 + Tax Rate ÷ 100)
     Tax Amount = Price - Price Before Tax
   If price doesn't include tax:
     Price Before Tax = Price
     Tax Amount = Price × Tax Rate ÷ 100

3. Multiple Items Tax:
   For each item:
     Item Total = Price × Quantity
     Item Tax = Item Total × Tax Rate ÷ 100
     Item Total With Tax = Item Total + Item Tax
   
   Subtotal = Sum of all Item Totals
   Total Tax = Sum of all Item Taxes
   Total With Tax = Subtotal + Total Tax

4. Tax Exempt Threshold:
   If Item Price < Tax Exempt Threshold:
     Item Tax = 0