Add GST & VAT calculator
The formula, a worked example, and the error this particular calculation tends to produce.
How it works
You have a net price and need the total to charge, plus the tax to report. This is the ordinary direction, and the one that goes wrong least often.
The formula
tax = net × rate ÷ 100 total = net + tax
- Pick the country, or type the rate you need.
- Keep "Add tax" selected and enter the amount before tax.
- Read the tax, the total, and the invoice split where one applies.
Worked example
| Item | Value |
|---|---|
| Before tax | ₹1,000.00 |
| rate | 18% |
| Tax | ₹180.00 |
| Total including tax | ₹1,180.00 |
The mistake to avoid
Rounding each line of an invoice and then summing, rather than summing and rounding once. On a long invoice the two differ by a cent or two, which is enough to fail a reconciliation.
Questions people ask
What is the difference between margin and markup?
Markup is profit as a share of cost; margin is profit as a share of the selling price. Cost 100 with a 50% markup sells at 150; cost 100 at a 50% margin sells at 200. They agree only at zero, and the gap widens as the percentage rises — at a 70% target the difference is more than double.
Should I apply my margin before or after tax?
Before. Consumption tax is collected on behalf of the government and was never your revenue, so the margin belongs on the tax-exclusive price. Taking the margin on the tax-inclusive figure understates your real margin and underprices the item.