Import invoices from Tally / Excel

Two paths to get invoices into a GST return: auto-sync (Tally / LedgrOS) and manual import (Excel / CSV).

Auto-sync (recommended)

If you've connected Tally or LedgrOS, invoices flow in automatically. Skip to Run 2B vs Purchase Register reconciliation.

Manual import

GST → Invoices → Import

1. Pick the period - the month/quarter you're importing for.
2. Choose direction - Outward (sales) or Inward (purchases).
3. Drag & drop your file - .xlsx, .xls, or .csv. Maximum 5 MB or 50,000 rows per file.
4. Map columns - the importer reads your first row as headers and lets you map each column to a ThynkTax field. Standard mappings (Invoice No, Date, GSTIN, Taxable Value, IGST, CGST, SGST, HSN, Place of Supply) are auto-detected.
5. Preview - first 20 rows are shown with any validation errors flagged (e.g. invalid GSTIN, missing HSN, place of supply mismatch with state).
6. Commit - invoices are saved as drafts. They appear on the return preparation screen.

Validation at import time

• GSTIN check - must be 15 chars and pass GSTN's checksum
• State code consistency - GSTIN state prefix vs Place of Supply
• Tax math - IGST vs CGST+SGST split inferred from inter-state vs intra-state
• HSN format - 4-digit for ≤₹5cr turnover, 6-digit for >₹5cr
• Duplicate check - same invoice number + supplier GSTIN + date is flagged

Errors block import; warnings are recorded but allow the import to proceed.

Edit after import

Every imported invoice can be edited from GST → Invoices. Edits are tracked in the audit log.

Re-importing

If you re-import the same file, ThynkTax uses upsert on (GSTIN + invoice number + date) - existing invoices are updated, new ones added. To force a clean slate, delete the period's drafts first.