How do I add GST to a price?

Multiply the net (pre-tax) price by the GST rate to get the GST amount, then add it back. For a net of 100 at 10 percent GST, the GST is 10 and the gross is 110. The calculator does this automatically in Add mode.

How do I remove GST from a GST-inclusive price?

Divide the gross price by 1 plus the rate. At 10 percent, divide by 1.10: a gross of 110 gives a net of 100 and a GST component of 10. Use Remove mode and the tool shows each step.

What GST rate does each country use?

The presets load common headline rates: Australia 10 percent, New Zealand 15 percent, Singapore 9 percent, India uses bands of 0, 5, 12, 18 and 28 percent, and Canada combines 5 percent federal GST with provincial HST totals of 13 or 15 percent. You can always override with a custom rate.

Why is removing GST not just subtracting the percentage?

Because the percentage is applied to the net price, not the gross. Subtracting 10 percent of a gross price over-removes the tax. The correct method is to divide by 1.10, which is what Remove mode does.

Does India GST work the same way in this tool?

Yes for the total tax. India splits GST into CGST plus SGST (or IGST for interstate), but the combined rate and the net/gross split are identical to what this calculator shows. Pick the band that applies to your goods or services.

Is my data sent anywhere?

No. Every figure is calculated locally in your browser. Nothing you type is uploaded, logged or stored on a server.

GST Calculator — Gera Tools

A GST calculator that adds Goods and Services Tax onto a net price or strips it back out of a tax-inclusive price, and shows the full working as it goes. It is built for freelancers, small businesses, online sellers and accountants in Australia, New Zealand, India, Canada and Singapore who need to split a figure into its net, tax and gross parts in seconds. Pick a country preset to load the right rate and label, or switch to a custom rate for anywhere else GST or a flat sales tax applies.

How it works

GST is a percentage tax charged on the net (pre-tax) value of goods and services. The two everyday questions are mirror images of each other, and this tool handles both.

When you add GST, your starting figure is the net price. The tax is net × rate, and the gross is net + tax. So a net of 100 at a 10 percent rate gives 10 of GST and a gross of 110.

When you remove GST, your starting figure already includes the tax, so you cannot simply subtract the percentage — that would over-remove it. Instead you divide the gross by 1 + rate. At 10 percent that means dividing by 1.10: a gross of 110 yields a net of 100, and the GST component is the difference, 10. The calculator runs whichever path you choose and prints each multiplication and division so you can check it by hand or copy it into an invoice.

Add: gross = net × (1 + rate) and tax = net × rate Remove: net = gross ÷ (1 + rate) and tax = gross − net

Country presets only set a sensible default rate and the right label (GST, or GST/HST in Canada). India exposes its full band structure of 0, 5, 12, 18 and 28 percent as quick-pick chips. You can override any preset by typing a custom rate, and you can display results in a local currency symbol or a neutral number with no symbol at all.

Worked example

A New Zealand consultant quotes a job at a net fee of 2,000 with GST at 15 percent. In Add mode the GST is 2000 × 15% = 300, so the gross invoice total is 2000 + 300 = 2,300.

Now suppose a customer hands you a GST-inclusive receipt for 2,300 and you need the GST portion for your return. In Remove mode the net is 2300 ÷ 1.15 = 2,000 and the GST is 2300 − 2000 = 300 — exactly reversing the first calculation.

Country	Rate	Net	GST	Gross
Australia	10%	100.00	10.00	110.00
New Zealand	15%	2,000.00	300.00	2,300.00
India	18%	500.00	90.00	590.00
Canada (HST)	13%	250.00	32.50	282.50

Every figure is computed in your browser — nothing is uploaded or stored.