GSTR-3B Calculator

Lejur One | Import 2B | classify | proportion reversal | tax liability
This is a GSTR-3B working calculator. It does not reconcile books with the GST portal. Use it to prepare proportionate ITC reversal, manual/RCM adjustments, and tax liability workings from 2B JSON plus your sales ratio inputs.

Imported rows

0
B2B + CDNR after normalization

Net ITC pool

0
IGST + CGST + SGST

Ratio taken

--
Taxable / total sales

Manual rows

0
Missing in 2B + RCM

Imported transactions

Search
CDNR shown as negative
SectionDateSupplierDoc NoTaxableIGSTCGSTSGSTCategory

Bucket totals

Sales & ratio

Add each sales line. Taxable rows carry a GST %. Exempt / nil-rated rows use 0%. Ratio and ITC reversal are recomputed on every change.
Sales typeAmount (Rs.)GST %TaxableOutput tax

Manual book-only entries

TypeSupplierTaxableIGSTCGSTSGST

Output Working

Import data and add sales entries to generate output.

Build path

Prototype: Browser UI proving the classification workflow, JSON import logic, manual adjustment flow, and monthly project export.
Production: Python service or desktop app to read GSTN 2B JSON, apply vendor rules, preserve monthly audit logs, write back to Excel.
Persistence: Save each month as a project JSON file and reopen it later.
Tools
Rule engine
Bansal / AJ Steels / Miyota -> Full claim
Dalmia -> Full GST Reverse
Road carriers / VRL -> RCM
Insurance / services -> Proportionate
Row editor

Use when auto-classification is wrong or CDNR should follow supplier's bucket.