Invoice Due Date & GST Calculator — Due Dates, GST Amount, Total

Invoice amount (₹)

GST rate (%)

Issue date

Payment terms (days)

GST amount

Total (incl. GST)

Due date

Status today

How to use the Invoice Due Date & GST Calculator

1 Enter the invoice amount (before GST).
2 Pick the GST rate — 18%, 12%, 5% or 0%.
3 Choose the issue date.
4 Set your payment terms in days (most agencies use 15-30 days).
5 Read the GST amount, total, due date and current status instantly.

GST invoicing made simple

If you bill clients in India, you need to charge GST correctly on every invoice. This calculator gives you the GST amount, the total including GST, and the due date — so your invoices are always accurate.

Payment terms that actually get you paid

Clear payment terms reduce late payments. State them on every invoice and send a reminder 3 days before the due date. Agencies using automated reminders get paid 2x faster.

Invoice Due Date & GST Calculator — FAQ

Most agency services (marketing, creative, website management) fall under 18% GST in India. Some services like advertising space can be 5%. Confirm with your CA.

GST amount = invoice amount × GST rate ÷ 100. Total = invoice amount + GST. For ₹1,00,000 at 18%: GST is ₹18,000 and the total is ₹1,18,000.

An invoice is overdue the day after its due date (issue date + payment terms). Late payment reminders usually start 3-7 days after the due date.

Most agencies use Net 15 or Net 30. In India, 15 days is common for retainers, and 30 days for project-based work.