Add or remove GST at any rate (5%, 12%, 18%, 28%)

GST Rate Variations by Country

GST is a broad-based consumption tax used in many countries at different rates. uses 5/12/18/28% slabs depending on category. 10%, 9%, New Zealand 15%, 6%, 11%. The math is identical; only the rate changes.

When to Add vs Remove

Add GST when pricing for customers — net cost plus GST equals retail price. Remove GST for accounting when recording inclusive totals — extract the net amount for revenue recognition separate from the tax collected on behalf of government.

Run it with sensible defaults

Using amount of 1,000, gst rate of 18, mode of 1, the calculation works out to 1,180.00. Nudge the inputs toward your own situation and the output recalculates instantly. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Amount, GST Rate, and Mode (0 = remove, 1 = add) — do not pull with equal force. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

How the math works

For adding GST, multiply amount by rate. For removing GST, GST equals amount minus amount divided by (1 + rate). The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".

Using the result to negotiate

The figure gives you a concrete number to quote when shopping alternatives. "I'm paying £X annually" cuts through marketing in a way "I want a better deal" doesn't. The specificity wins.

What this doesn't capture

Usage varies month-to-month; tariffs change; discounts come and go. The figure here is a clean baseline — your actual annual bill will fluctuate around it. Use the calculation to benchmark providers, not as a prediction of a specific bill.