What is GST Calculator?
A GST calculator works out the tax on a transaction in either direction: adding GST to a price that excludes it, or extracting the GST already embedded in an inclusive price. The second case is the one people get wrong. To remove 18% GST from ₹1,000 you do not subtract 18% — you divide by 1.18. The difference is ₹27, which compounds quickly across a book of invoices.
Indian GST splits differently depending on where the supply goes. Within a state, the rate is divided evenly into Central GST and State GST — an 18% rate becomes 9% CGST plus 9% SGST, shown as separate lines on the invoice. Across state lines it is a single Integrated GST line at the full 18%. This calculator shows the correct split for both, which is what you actually need when preparing an invoice or checking one you have received.
The standard slabs are 5%, 12%, 18%, and 28%, with 0% for exempt goods and 3% for gold and precious metals — all available as one-tap presets, with a free-entry field for anything else. The examples below use rupees because the CGST/SGST/IGST split is specific to India, but the calculator itself works in any of ten currencies, so the same arithmetic covers Australia's 10% GST, New Zealand's 15%, and Singapore's 9%. Everything runs in your browser, so invoice figures and client amounts never leave your device.
Use Cases
Here are the most common ways people use GST Calculator every day.
Preparing a GST Invoice
You quoted a client ₹50,000 plus tax. The invoice needs the taxable value, the CGST and SGST lines at 9% each, and the total. Enter 50,000, pick 18%, keep intra-state selected, and every line is there in the format a compliant tax invoice requires. Getting the split right matters — an invoice showing IGST when it should show CGST and SGST creates input-credit problems for your client.
Extracting GST From an Inclusive Price
A vendor bills you ₹11,800 all-inclusive and you need the taxable value for your books and your input tax credit claim. Switch to remove mode: the taxable value is ₹10,000 and the GST is ₹1,800. Doing this by subtracting 18% would give ₹9,676 — wrong, and it would understate the credit you are entitled to claim.
Pricing a Product for Retail
You want a shelf price of ₹499 including GST at 18%. Remove mode tells you the taxable value is ₹422.88 and the tax is ₹76.12. Now you know what margin you actually have. Consumers see one number; your accounting sees two, and setting the round price first and working backwards is how most retail pricing is done.
Freelancer and Consultant Billing
Services are generally taxed at 18%. A freelancer registered under GST billing an out-of-state client charges IGST at 18% as a single line; billing a client in the same state, it splits into CGST and SGST. Choosing the wrong one is one of the most common errors on freelance invoices, and the supply-type toggle here makes the correct format obvious.
Checking a Bill You Have Received
Restaurant, hotel, and vendor bills sometimes carry the wrong rate or arithmetic that does not add up. Enter the pre-tax total and the rate that should apply, and compare against what you were charged. Restaurants are generally 5% without input credit; hotel rooms vary by tariff; most goods and services are 18%.
Reconciling Books at Filing Time
When totals in your accounting software disagree with your GSTR filings, the discrepancy is often a handful of entries where GST was added to an already-inclusive figure, or removed by subtraction rather than division. Re-running the disputed entries here isolates which ones are wrong in a couple of minutes.
Examples
Adding GST for an In-State Client
A ₹50,000 consulting fee to a client in the same state at 18%.
₹50,000 · 18% · add · intra-state Taxable ₹50,000 · CGST ₹4,500 · SGST ₹4,500 · Total ₹59,000 Removing GST From an Inclusive Bill
A ₹1,000 inclusive invoice at 18%, to find the taxable value for input credit.
₹1,000 · 18% · remove Taxable ₹847.46 · GST ₹152.54 · Total ₹1,000 Inter-State Supply
The same ₹50,000 fee billed to a client in another state.
₹50,000 · 18% · add · inter-state Taxable ₹50,000 · IGST ₹9,000 · Total ₹59,000 GST Calculator vs accounting software
Full accounting software handles GST as part of your ledger. A standalone calculator fits a different moment.
| Feature | Toolorah | accounting software |
|---|---|---|
| Cost | Free | ₹5,000–₹30,000 per year |
| Speed for a one-off check | Seconds | Log in, find the right screen |
| CGST / SGST / IGST split | Yes | Yes |
| Reverse (inclusive → exclusive) | Yes | Sometimes buried in settings |
| Generates a filing-ready invoice | No | Yes |
| GSTR return filing | No | Yes |
| Data leaves your device | Never | Stored on their servers |
Tips for Using GST Calculator
- To remove GST, divide by (1 + rate/100) — never subtract the percentage. Subtracting 18% from an inclusive price always understates the taxable value.
- Intra-state supply splits the rate into equal CGST and SGST halves; inter-state is a single IGST line at the full rate. The place of supply, not your location, decides which applies.
- Most services are 18%. Restaurants are usually 5% without input tax credit. Check the current HSN or SAC code for goods — rates are revised periodically by the GST Council.
- Round only at the invoice total, not on each line. Rounding every line separately is how invoices end up off by a rupee.
- Keep the taxable value and tax as separate fields in your records — you need both for GSTR filings and for claiming input tax credit.
Frequently Asked Questions
How do I remove GST from an inclusive amount?
Divide the inclusive amount by (1 + rate/100). For 18% GST on ₹1,180, that is 1180 ÷ 1.18 = ₹1,000 taxable value, with ₹180 as the GST. The common mistake is subtracting 18% of the inclusive figure, which gives ₹967.60 — about 3% too low. The error grows with the rate: at 28% GST, subtracting instead of dividing is off by more than 7%.
What is the difference between CGST, SGST, and IGST?
CGST goes to the central government and SGST to the state government; together they apply to supplies within a single state, splitting the total rate evenly. IGST applies to supplies between states and is collected by the centre at the full rate, then apportioned. For an 18% supply: intra-state is 9% CGST plus 9% SGST, inter-state is 18% IGST. The total tax is identical either way — only the split and the recipient differ. Union territories use UTGST in place of SGST.
What are the current GST rates in India?
The main slabs are 5%, 12%, 18%, and 28%. Essential goods are exempt at 0%; gold and precious stones are 3%. Broadly: basic foods and healthcare are exempt or 5%, processed foods and business-class travel are 12%, most goods and services including consulting and software are 18%, and luxury and demerit goods such as cars and tobacco are 28% plus a cess. Rates are revised periodically by the GST Council, so check the current notification for a specific HSN or SAC code before relying on any figure.
Which rate applies to my product or service?
It depends on the HSN code (goods) or SAC code (services) that classifies it. There is no shortcut — the same broad category can span slabs, and misclassification is a genuine compliance risk. The official GST rate finder on the CBIC portal is the authoritative source. For most professional and IT services, 18% is correct.
Do I need to register for GST?
Registration is generally mandatory once annual turnover exceeds ₹40 lakh for goods or ₹20 lakh for services, with lower thresholds in special-category states. Inter-state suppliers and e-commerce sellers must register regardless of turnover. There are exceptions in both directions, so confirm your position with a chartered accountant rather than relying on the threshold alone.
Can I use this calculator for VAT or sales tax in other countries?
The arithmetic is identical for any single-rate value-added tax — UK VAT at 20%, Australian GST at 10%, UAE VAT at 5%. Enter that rate and use add or remove as needed. The CGST/SGST/IGST split is India-specific; for other countries just read the total tax line and ignore the split.
Is the GST amount rounded?
Displayed figures are rounded to two decimal places, matching invoice conventions. Under Indian rules, the total tax payable on an invoice is rounded to the nearest rupee. Round once at the invoice total rather than on each line item — rounding line by line is the usual cause of invoices that are off by a rupee against the customer's own calculation.
Is my data stored anywhere?
No. The calculation runs entirely in your browser in JavaScript. Amounts you enter are never uploaded, logged, or stored, which means client fees and invoice values are safe to enter here. Closing the tab clears everything.