GST (Goods and Services Tax) liability is the amount of tax your business owes to the government every month after accounting for both the GST collected on sales and the GST paid on purchases (input tax credit). Simply put:

GST Liability = GST Collected on Sales – Input Tax Credit (GST Paid on Purchases)

Step 1: Keep Track of Your Sales and GST Collected

First, maintain detailed records of all your sales invoices during the month. For every product or service you sell, you charge GST at the applicable rate (typically 5%, 12%, 18%, or 28%). The GST collected from your customers forms your output tax.

Tip: Use a simple ledger or accounting software to record invoice dates, amounts, and GST charged. This practice helps avoid last-minute confusion and errors.

Step 2: Record Your Purchases and Input Tax Credit

Next, gather all purchase invoices where you have paid GST to your suppliers. This GST paid is called the input tax and can be claimed as an input tax credit to offset your GST liability.

Ensure that you only claim input tax credit for purchases used for business purposes and that the invoices are GST-compliant.

Step 3: Calculate Your Taxable Turnover

Add up your total sales excluding GST. This figure is your taxable turnover and is important because it determines the GST bracket applicable to your business.

Step 4: Determine Your Output GST

Apply the correct GST rate to your taxable turnover to find out how much GST you have collected from customers.

Step 5: Calculate Input Tax Credit

Add up all the GST amounts you paid on your business purchases for the month.

Step 6: Calculate Your Net GST Liability

Subtract the input tax credit from the output GST collected:

Net GST Liability = Output GST – Input Tax Credit

If the result is positive, that is the amount you need to pay to the government. If it’s negative, you have an input tax credit balance to carry forward.

Step 7: File Your GST Returns on Time

In Bihar and across India, GST returns must be filed monthly through the government portal by the due date. Accurate calculation ensures timely filing, avoiding late fees and legal trouble.

Task	Description	Done (✓)
Collect and organize all sales invoices	List every sale with GST charged
Collect all purchase invoices	List every purchase with GST paid
Verify GST rates on sales	Confirm correct GST rate applied
Verify GST on purchases	Check for valid GST invoices
Calculate total sales turnover	Sum of sales excluding GST
Calculate output GST	GST collected on sales
Calculate input tax credit	GST paid on purchases
Compute net GST liability	Output GST – Input tax credit
Prepare GST payment	If liability positive, arrange payment
File GST returns before due date	Submit online filing