GST Compliance Calendar April 2021:
| Due Date | Forms to be filed | Taxpayer Type | Period |
| 10-04-2021 | GSTR-7 | Taxpayer who is required to deduct TDS as per GST Act | Mar-21 |
| 10-04-2021 | GSTR-8 | Taxpayer who is required to collect TCS as per GST Act | Mar-21 |
| 11-04-2021 | GSTR-1 | Normal Registered Taxpayer who has not opted for Quarterly Return Monthly Payment (QRMP) Scheme | Mar-21 |
| 13-04-2021 | GSTR-6 | A taxpayer having registration of Input Service Distributor (ISD) | Mar-21 |
| 13-04-2021 | GSTR-1 | Registered Taxpayer who has opted for Quarterly Return Monthly Payment (QRMP) Scheme | Jan-21 – Mar-21 |
| 20-04-2021 | GSTR-3B | Normal Registered Taxpayer who has not opted for Quarterly Return Monthly Payment (QRMP) Scheme | Mar-21 |
| 20-04-2021 | GSTR-5 | Non-Resident Taxpayer | Mar-21 |
| 20-04-2021 | GSTR-5A | OIDAR | Mar-21 |
| 22-04-2021 | GSTR-3B | Registered Taxpayer who has opted for Quarterly Return Monthly Payment (QRMP) Scheme | Jan-21 – Mar-21 |
| 24-04-2021 | GSTR-3B | Registered Taxpayer who has opted for Quarterly Return Monthly Payment (QRMP) Scheme | Jan-21 – Mar-21 |
Income Tax Compliance Calendar April 2021:
| Due Date | Taxpayer Type | Period |
| 07-04-2021 | A taxpayer who is required to collect TCS | Mar-21 |
| 30-04-2021 | A taxpayer who is required to deduct TDS | Mar-21 |
| 30-04-2021 | The due date for uploading declarations received from recipients in Form. 15G/15H | Jan-21 – Mar-21 |
Professional Tax – Karnataka:
| Due Date | Taxpayer Type | Period |
| 20-04-2021 | Monthly P.T Remittance And Filing of Returns | Mar-21 |
| 30-04-2021 | P.T Annual Returns (FORM 5) | F.Y.20-21 |
| 30-04-2021 | P.T Annual Payment Of Enrolment Tax | F.Y.21-22 |