Key points
- The IRP shares each e-invoice with the GST system and the e-way bill system, which creates Part-A from it.[1][2]
- Transport details (transporter ID, vehicle number, distance) can go in with the e-invoice request, or be added later by IRN.[1][2]
- Distance is auto-calculated from the pincodes; you can enter up to 10% more or less. Same pincode at both ends: 1 to 100 km.[2]
- An IRN cannot be cancelled once its e-way bill is generated or active, and IRN cancellation is allowed only within 24 hours.[2]
- Part-B updates, extension and e-way bill cancellation happen on the e-way bill portal, with the same login.[2]
What happens behind the scenes
- Your software sends the e-invoice JSON to the IRP. The schema includes optional fields like transporter ID and vehicle number.[1]
- The IRP validates the invoice, returns the IRN and the signed QR code, and passes the invoice to the GST system (for GSTR-1) and the e-way bill system.[1]
- The e-way bill system builds Part-A from the invoice. If you sent transport details too, the e-way bill is generated at once.[1][2]
- If not, you (or your software) generate it later by entering the IRN, acknowledgement number or invoice date, and adding the transport details.[2]
What you still fill
| Field | Where it comes from | Notes |
|---|---|---|
| Supplier, buyer, items, values, HSN | The e-invoice (Part-A) | Nothing to retype |
| Transporter name and ID | You | Needed if a transporter will update Part-B |
| Approximate distance (km) | Auto from pincodes | You may enter up to ±10% of the auto distance; same pincode: 1–100 km[2][3] |
| Mode and vehicle type | You | Road, rail, air or ship |
| Vehicle number or transport document | You | Can be added later in Part-B on the e-way bill portal[2] |
Remember that a road e-way bill is not valid for movement until Part-B is filled, except for short hauls of up to 50 km within the state to or from the transporter.[4]
Validity and the 200 km rule
Validity is counted the same way as for any e-way bill: one day for every 200 km or part of it for normal cargo, since 1 January 2021.[3] It starts when Part-B is first entered. See our e-way bill validity guide and the validity calculator.
Cancelling: the order matters
Mistakes happen, and the two documents are linked:
- An IRN can be cancelled only within 24 hours of generation, and not if its e-way bill is already generated or active. The invoice number of a cancelled IRN cannot be used again.[2]
- An e-way bill can be cancelled within 24 hours of generation if goods were not moved or not moved as per its details, unless it has been verified in transit.[4]
- So if both are wrong: cancel the e-way bill first, then the IRN, both inside 24 hours. After that window, the IRN stands; corrections go through a credit note or an amendment in GSTR-1, never through the IRP.[1]
Worked example
Gupta Electricals, Lucknow (sample firm) bills a contractor in Kanpur at 11:40 am on 16 October 2026.
| Item | Value |
|---|---|
| Taxable value | ₹1,72,000 |
| CGST 9% + SGST 9% | ₹30,960 |
| Invoice total | ₹2,02,960 |
| Auto distance (pin to pin) | 88 km |
| Distance entered | 92 km (within +10%) |
| Validity | 1 day: valid until 23:59 on 17-10-2026 |
The billing operator saves the bill with the transporter ID filled. The IRN and the e-way bill come back together. The transporter adds the truck number in Part-B at 5 pm; validity runs from then to midnight of the next day, as the first day ends at midnight of the day after.[3] If the truck changes on the way, the transporter updates Part-B again before the goods move.[4]
Common problems and fixes
| Problem | Cause | Fix |
|---|---|---|
| Distance refused | Entered more than 10% above or below the pin-to-pin distance | Use the auto distance, or a figure within ±10%[2] |
| E-way bill not valid at a check | Part-B (vehicle) never filled | Add the vehicle number on the e-way bill portal before the goods move[4] |
| Truck changed on the way | Breakdown or transhipment | Update Part-B with the new vehicle before moving again[4] |
| Wrong buyer or value on the invoice | Data error in the e-invoice | Cancel the e-way bill, then the IRN, within 24 hours, and issue a fresh bill[2][4] |
| E-way bill requested before IRN came back | Timeout during IRN generation | Fetch the IRN first; never resend the invoice (avoids error 2150) |
Who does what on the dispatch desk
| Person | Job | When |
|---|---|---|
| Billing operator | Saves the bill; IRN and Part-A come back | At billing |
| Dispatch clerk | Adds the transporter ID and checks the distance | Before loading |
| Transporter | Fills or updates Part-B with the vehicle number | Before the truck moves, and whenever the vehicle changes[4] |
| Accountant | Watches validity and extends if a load is delayed | Within 8 hours either side of expiry[3] |
When you can't use the IRN route
- B2C sales and other documents that are not e-invoiced have no IRN.
- Movements that are not supplies, such as goods sent to a job worker or to your own godown on a delivery challan.
- Purchases from unregistered persons where you, the buyer, cause the movement.
For these, generate the e-way bill on the e-way bill portal directly, or in bulk with the portal's tool. See bulk e-way bill generation.
How Moharbill helps
- IRN and e-way bill are requested when you save the bill, with checks before the IRP so common rejections are caught first. See e-invoice software.
- Distance is filled from the pincodes, inside the ±10% band.
- Part-B updates and extensions are one action from the e-way bill screen.
- Standalone e-way bills without an IRN arrive in v1.1.
Frequently asked questions
Can I generate an e-way bill from an IRN?
Yes. The IRP passes the e-invoice to the e-way bill system, which creates Part-A. You add transport details, either in the e-invoice request or later by entering the IRN.
Do I need a separate login for the e-way bill?
No. E-way bills generated through the e-invoice system appear in the e-way bill system, and you use the same credentials there to update Part-B, extend or cancel.
Can I cancel an IRN after its e-way bill is generated?
No. Cancel the e-way bill first. IRN cancellation is allowed only within 24 hours of generation and not while its e-way bill is active.
How much can I change the distance?
Up to 10% more or less than the auto-calculated pin-to-pin distance. If both pincodes are the same, between 1 and 100 km.
Is an e-way bill without a vehicle number valid?
Not for movement by road. Part-B must be filled before the goods move, except for short hauls of up to 50 km within the state to or from the transporter.
Sources
All read on 17 Oct 2026.
- NIC, "e-invoice/IRN System – Detailed Overview" (IRP shares data with GST and e-way bill systems; transporter fields in the schema; amendments only in GSTR-1). einvoice1.gst.gov.in
- NIC, e-invoice system web user manual (Part-A from IRN; generate e-way bill by IRN; ±10% distance, same pincode 1–100 km; IRN cancellation within 24 hours and not when the e-way bill is active). einvoice1.gst.gov.in
- NIC e-way bill documents page: validity changed to 200 km per day from 01-01-2021 (Notification 94/2020-CT); advisory on extending validity within 8 hours before or after expiry. docs.ewaybillgst.gov.in
- CGST Rules 2017, rule 138 (Part-B, 50 km relief, transfer between vehicles, cancellation within 24 hours), CBIC. taxinformation.cbic.gov.in
Written by the Moharbill team
We build GST billing for distributors at Hexa Secure Labs and write these guides from the rules we code into the product. Spotted something out of date? Tell us and we will fix it within two working days.