GST (Goods and Services Tax) is added to the price of many goods and services, and knowing how to calculate it helps both shoppers and businesses. This guide explains how to add and remove GST and how Camera Calculator: Math Solver helps you do the maths for free.
GST is a consumption tax applied to the sale of goods and services in many countries. It is charged as a percentage of the price, and the exact rate varies by country. Understanding how it is calculated helps you check receipts, set prices and avoid surprises at the till.
To add GST to a price that excludes it, work out the GST amount by multiplying the price by the GST rate and dividing by 100, then add it to the original price. For example, adding 10 per cent GST to 200 means calculating 10 per cent (which is 20) and adding it to get 220. This gives you the GST-inclusive price.
To find the pre-GST price from a GST-inclusive total, divide the total by one plus the rate as a decimal. For a 10 per cent rate, divide the inclusive price by 1.1. The difference between the inclusive price and this figure is the GST amount. This is useful for businesses working out the tax portion of their sales.
Camera Calculator: Math Solver makes GST calculations quick. Use the calculator to add or remove GST with the formulas above, or scan a written problem with the camera. It is handy for shoppers checking prices and for businesses pricing products and preparing invoices. For related maths, see our percentage calculator and tax calculator guides.
Always be clear whether a price includes or excludes GST before you calculate, as mixing the two causes errors. Use the correct rate for your country, and double-check totals on invoices. For business accounting, keep your GST-inclusive and GST-exclusive figures clearly labelled.
How do I add GST? Multiply the price by the rate, divide by 100, and add it on. How do I remove GST? Divide the inclusive price by one plus the rate as a decimal. Can Camera Calculator do this? Yes, on the calculator or by scanning. Is it free? Yes.
GST affects both sides of every transaction. For shoppers, it explains why the price at the till can differ from the shelf price, and knowing how to calculate it helps you check receipts and budget accurately. For businesses, GST is a legal responsibility: they must charge it correctly, keep clear records, and often report and pass it on to the authorities. Getting GST calculations right is therefore not just convenient but important, and understanding the simple maths behind it gives both shoppers and business owners confidence that the figures add up.
The most common source of GST confusion is mixing up inclusive and exclusive prices. A GST-exclusive price does not yet contain the tax, so you add it on; a GST-inclusive price already contains it, so to find the tax portion you work backwards. Being crystal clear about which type of price you are dealing with before you calculate prevents almost all GST errors. When quoting or comparing prices, it is good practice to state explicitly whether GST is included, both for your own accuracy and to avoid misunderstandings with customers.
For a small business, handling GST well is part of running things properly. That means charging the correct rate, issuing clear invoices that show the GST amount, and keeping your inclusive and exclusive figures neatly separated for accounting. Quick, accurate calculations make this far less of a chore, whether you are pricing a new product or preparing a return. While an app handles the arithmetic, always follow the specific GST rules and rates that apply in your country, and keep good records so your figures can be checked when needed.
GST, and the closely related value-added tax, exists in many countries, but the rate varies widely from place to place, and some goods are taxed at reduced rates or exempt entirely. This is why it is essential to use the correct rate for your own country when calculating. The method stays the same regardless of the rate — you add or remove a percentage — but plugging in the wrong figure gives a wrong answer. If you trade internationally, you may need to handle different rates for different markets. Keeping a note of the rates that apply to you, and using them consistently, ensures your GST calculations are always accurate wherever you are doing business.
Knowing how to calculate GST helps you shop and sell smarter. Download Camera Calculator: Math Solver free and handle GST in seconds. See also our business calculator guide.
