Why GST and e-way bills are a warehouse problem, not just an accounts problem
In most Indian businesses, GST is treated as something the accounts team handles at month-end. But GST and the e-way bill are triggered by a physical event — goods leaving the warehouse — and the details they depend on (which items, which HSN codes, what taxable value, which vehicle, from which place to which place) are created on the warehouse floor. When the floor and the books are disconnected, you get the familiar problems: e-way bills generated for the wrong quantity, invoices that do not match the challan, stock that shows in Tally but is not physically there, and vehicles held at check-posts because the paperwork does not line up with the load.
A warehouse management system closes that gap. Fast WMS treats dispatch, tax invoicing and e-way bill data as one connected chain that starts at the barcode scan and ends at a Tally voucher — so the compliance document is built from the real movement, not re-keyed from memory hours later.
Where GST touches the warehouse workflow
GST is not a single step at the end. It threads through the whole inbound-to-outbound flow. Fast WMS holds tax configuration per company and per document type, and applies the correct treatment automatically at each point where tax is relevant.
The important design point is that the tax is derived from masters — the item's HSN and rate, the party's state and GSTIN — not typed by the person raising the invoice. That is how you get a consistent CGST/SGST versus IGST decision every time, and an accurate HSN-wise tax summary at the foot of every invoice.
The e-way bill: thresholds, Part A / Part B, and validity
An e-way bill (EWB) is an electronic document generated on the GST e-way bill portal before goods worth more than a threshold are moved. Knowing exactly when it is required, and how long it lasts, is what keeps a consignment from being detained.
When is it required?
- Consignment value above Rs 50,000 (including GST) — for a supply, a stock or branch transfer, an inward supply from an unregistered person, or a return.
- For inter-state movement above the threshold, and for intra-state movement where the state has adopted the same limit (some states set their own).
- Even without a sale — job-work, line sales, exhibition, SKD/CKD, and own-warehouse transfers all count as movement of goods.
Part A and Part B
An e-way bill has two parts. Part A carries the consignment details — GSTINs of supplier and recipient, place of dispatch and delivery, invoice or challan number and date, HSN code, item value and the tax amounts. Part B carries the transport details — the vehicle number (or transporter document number). The bill is only valid for movement once Part B is filled, and validity is counted from that moment.
Validity
Validity is distance-based, counted from the time Part B is generated: broadly one day for every 200 km of approximate distance for regular cargo, with a longer factor for over-dimensional cargo. If a truck breaks down or a journey runs long, the transporter can extend validity before it expires. Because a WMS stamps the exact gate-out time and the true consignment details, the validity window is calculated from an accurate starting point rather than a rough guess.
How a WMS handles dispatch, invoicing and e-way bills
Here is the sequence Fast WMS runs when an order ships, and where each compliance artefact is produced.
Want to see dispatch → invoice → e-way bill → Tally in one flow?
We can run a live 30-minute walkthrough on your own item masters, HSN codes and GST rates — and show exactly where each compliance document comes from.
Why invoicing never touches your stock
One principle in Fast WMS matters more than any other for GST accuracy: invoicing is financial only, and never changes stock. Physical stock leaves in two legs — pallet quantity at pick-confirm, and the bin balance at dispatch or gate-out. The tax invoice is raised afterwards from the un-invoiced dispatch balance.
This separation is not a technicality. It is what keeps physical stock and book stock reconciled. If invoicing moved stock, then a cancelled or amended invoice would silently change your on-hand quantity, and a part-invoiced dispatch would leave stock in limbo. By keeping the goods movement (challan) and the money movement (invoice) as distinct events, both the e-way bill (which follows the goods) and the GST return (which follows the invoice) rest on clean, independent records.
| Event | Moves stock? | Compliance artefact |
|---|---|---|
| Pick confirm | Yes — pallet qty | Internal allocation |
| Dispatch / gate-out | Yes — bin balance | Delivery challan + e-way bill (Part A data) |
| Tax invoice | No | GST tax invoice → Tally sales voucher |
| Sales return | Yes — stock re-added | Auto credit note |
Stock transfers and branch movements
A common trap is assuming an e-way bill is only for sales. It is not. Any movement of goods above the threshold needs one — including moving your own stock between two locations that have different GSTINs, such as shifting finished goods from a factory store to a regional distribution warehouse in another state.
Fast WMS records such a movement as a store transfer, producing the delivery challan and the stock-journal data that both the e-way bill and Tally require. Because the transfer is a first-class document in the system — not an invoice pretending to be a transfer — the value used for the e-way bill and the accounting treatment (a stock journal, not a sale) are both correct. For businesses running multiple warehouses or plants, this keeps inter-branch movement fully traceable and audit-ready.
Factory store in Pune to distribution hub in another state
Finished goods are picked and gated out of the Pune store on a delivery challan. Because the receiving hub is a different GSTIN and the consignment crosses Rs 50,000, an e-way bill is generated from the challan's Part A data. Fast WMS posts a stock journal in Tally at both ends — no sale, no GST liability created wrongly — and the goods stay traceable pallet-by-pallet from gate-out to gate-in.
The Tally hand-off
Fast WMS integrates with Tally ERP 9 and TallyPrime through a store-to-godown mapping. The rule is simple: every warehouse transaction posts the matching accounting voucher automatically, so the accounts team never re-keys a movement.
Deeper detail on the mechanism is in our WMS and Tally integration guide, and the dispatch document itself is covered under Dispatch & Invoicing.
Common compliance mistakes a WMS prevents
Challan and invoice don't match
When goods move on one document and are billed on another, quantities drift. A WMS builds both from the same confirmed dispatch, so the e-way bill matches the invoice exactly.
Prevented at dispatchExpired e-way bill at the check-post
Validity is missed when the start time is fuzzy. A scan-stamped gate-out gives an accurate clock, so validity is planned from a real dispatch time.
Accurate gate-out timeTransfers billed as sales
Branch movements wrongly invoiced create phantom GST liability. A WMS records the transfer as a stock journal, not a sale.
Correct document typeFrequently asked questions
When is an e-way bill required for warehouse dispatch in India?
An e-way bill is required whenever goods worth more than Rs 50,000 (single consignment value, including GST) move — whether for a sale, a branch or stock transfer, a job-work movement, or a sales return. It is needed for inter-state movement and, above the state threshold, for intra-state movement. Fast WMS captures the dispatch and invoice details the portal needs — invoice number, HSN, taxable value, GST split and transporter details — at the moment goods leave the warehouse.
Does creating a GST invoice reduce warehouse stock?
No. In Fast WMS invoicing is a financial event only — it never changes stock. Physical stock leaves in two legs: pallet quantity at pick-confirm, and the bin balance at dispatch or gate-out. The tax invoice is raised from the un-invoiced dispatch balance afterwards. Separating the goods movement from the invoice keeps physical stock and book stock reconciled, and keeps the e-way bill tied to the actual dispatch.
How long is an e-way bill valid?
E-way bill validity is distance-based: roughly one day for every 200 km of approximate distance for regular cargo (and one day per 20 km for over-dimensional cargo), counted from the time Part B (vehicle details) is generated. If the vehicle cannot complete the journey in time, the transporter can extend validity before it expires. A WMS helps by stamping the exact dispatch time and consignment details, so validity is calculated from an accurate start point.
Do I need an e-way bill for stock transfer between my own warehouses?
Yes, if the consignment value crosses the threshold. A branch or stock transfer between two GSTINs — for example moving finished goods from a factory store to a distribution warehouse in another state — is a movement of goods that requires an e-way bill even though there is no sale. Fast WMS records the transfer as a store movement and produces the delivery challan and stock-journal data the e-way bill and Tally both need.
How does Fast WMS hand GST data over to Tally?
Fast WMS holds tax configuration per company and document type and applies the correct CGST/SGST/IGST split on every dispatch invoice. When a GRN is confirmed it posts a purchase receipt voucher to Tally; when goods are dispatched it posts a sales voucher with the customer, items, GST and challan reference; a stock transfer posts a stock journal. The accounts team never re-keys a warehouse transaction, so GSTR returns are built on data that already matches the physical movement.