A GST calculator app maker lets shop owners, accountants and students build a fast tool for the sums they do all day: add GST to a price, take it out of a price that already includes it, and split it correctly. Describe the rates and the screens, the AI agent writes the app, you check a few figures in the emulator preview and download the APK. Rates stay in an editable list, so the app keeps up when they change.
What your GST calculator app will have
From the idea above, the agent builds:
- Calculator — an amount field, rate buttons and a clear Add GST / Remove GST switch.
- Breakdown — base amount, GST amount and total, with CGST and SGST halves for sales within a state or a single IGST line for sales to another state.
- Rate settings — the list of rate buttons, which you can add to, edit or remove.
- History — every calculation with the time, the rate and the mode, tap to reuse.
- Bill mode — several items with their own rates, a subtotal per rate and a grand total.
- Share — send the breakdown as text to a customer or a colleague.
A quick check: 1,000 plus 18% GST is 1,180, split into CGST of 90 and SGST of 90. Remove GST from 1,180 at 18% and you are back to 1,000.
Features you can ask for
- Indian number formatting with lakh and crore separators, like 12,34,567.
- A round-off line that rounds the total to the nearest whole number and shows the difference.
- A discount before GST, as a percentage or a fixed amount.
- Your shop name, GSTIN and address at the top of shared bills.
- An HSN or SAC code field per item, from a list you maintain.
- An interface in Hindi, Marathi, Tamil or another language.
- A daily total of GST collected from the bills you saved.
Ideas to make it yours
For full bills with numbering and customer records, read the bill and invoice app guide. Tracking stock as well as sales? The inventory and sales app guide shows how. For more on formulas and rounding, see building a calculator app.
Get it on your phone
- Press Build this GST calculator app and sign in with Google.
- In the emulator preview, try a price that includes GST and one that excludes it, and check the CGST, SGST and IGST lines.
- Ask for changes in plain words: "make IGST the default", "add a 3% button", "bigger total".
- Press Download APK and install it on your Android phone and your staff's phones.
- For Google Play, build the signed APK and AAB from the same menu; the APK builder page explains the steps.
Always test Remove GST with a known bill. Many quick calculators wrongly subtract 18% of the total; the correct method divides by 1.18, and your app should match your last real invoice to the paisa.
Keep the rates editable
GST rates in India are revised from time to time, and a calculator with rates built into its code goes out of date without warning. Ask the agent for rate buttons that come from a list in Settings, with the date you last reviewed them shown on screen. Keep the app focused on arithmetic: it calculates what you tell it, and a short note can remind users that the right rate for a product and anything about filing are questions for official sources or a tax professional. That keeps the app honest, simple and useful for years.
Frequently asked
How does the app remove GST from a price that already includes it?
It divides the price by 1 plus the rate. For example, 1,180 including 18% GST splits into a base of 1,000 and GST of 180. Adding GST works the other way: the base times the rate, added on top.
What if GST rates change?
Rates are revised from time to time, so ask for the rate buttons to come from an editable list in Settings. When a rate changes, you update it in the app without a new build.
Is this app tax advice?
No. It does the arithmetic for the rate you choose. Which rate applies to a product and how to file returns are questions for official sources or a tax professional, and the app can say so in a short note.
Can it make a GST bill for customers?
Yes. Ask for a bill mode with several items, each with its own rate, your shop details and a Share button. For full invoices with numbering and customer records, see the bill and invoice app guide.
Does it work offline?
Yes. All calculations and the history stay on the phone, so it works in the shop without internet.
Make your GST calculator app now — free to start
Describe it, sign in, and the agent builds it while you watch. Change anything by asking.
Build this GST calculator app ›