Gross vs Net Price After Tax

The words gross and net flip meaning depending on context — which causes consistent confusion in pricing, accounting, and payroll. Here is a clear reference for the retail and tax context.

In pricing and VAT/GST contexts

Term	Meaning	Also called
Net price	Price before tax	Ex-tax, exclusive price, base price
Gross price	Price after tax is added	Inc-tax, inclusive price, total

A product with a net price of $100 at a 10% tax rate has a gross price of $110.

Note: In payroll, "gross" and "net" reverse — gross pay is before deductions, net pay is after. This article covers the pricing / tax context.

The two calculation directions

Adding tax (net → gross):

Gross = Net × (1 + tax rate)

Example: $80 net + 20% VAT = $80 × 1.20 = $96 gross

Extracting tax (gross → net):

Net = Gross ÷ (1 + tax rate)
Tax amount = Gross − Net

Example: £120 including 20% VAT → Net = £120 ÷ 1.20 = £100, VAT = £20

A common error is to subtract 20% from the gross (120 × 0.20 = £24 ≠ £20). Always divide by (1 + rate), do not subtract a percentage from the gross total.

When to use each direction

• Retail checkout: Customer pays gross. Display both net and tax on the receipt for transparency and compliance.
• B2B invoice: Show the net price per line, sum lines, then add tax. Your customer needs the net amount to claim an input tax credit.
• Margin calculation: Always compute margin on net prices — including tax in both revenue and cost inflates turnover without changing profit.
• Discount applied before tax: Reduce the net price first, then apply tax on the discounted net. Jurisdiction rules vary on whether discounts apply before or after tax collection.

Multi-rate scenarios

When a basket contains items at different tax rates (e.g., food at 0%, clothing at 20%), calculate each line separately and sum:

Total tax = Σ (Net_i × rate_i)
Total gross = Total net + Total tax

Most accounting software handles this automatically, but knowing the formula helps you audit output.

Use GST / VAT for both add and extract directions, and the Discount Calculator when promotions apply before tax is calculated.