Temporary GST Number: TRN and Temporary ID Explained

Someone asking for a temporary GST number is usually in the middle of a registration and holding a TRN, the Temporary Reference Number the portal issues after the first half of the form. Less often they mean the temporary ID an officer assigns to an unregistered person, or a casual registration that expires after a trade fair. All three are real; none of them is a GSTIN. This guide explains each one and the mistake they share: treating them as if they allowed you to charge GST.

Three things called a "temporary GST number"

TRN: the temporary reference number

Registration in Form REG-01 happens in two halves. Part A asks for the legal name as per PAN, the PAN, the state, and the mobile number and email of the primary authorised signatory. The portal validates the PAN against the income tax database, sends an OTP to both the mobile and the email, and once both are verified, issues the TRN.

The TRN is a placeholder for an application in progress. It lets you close the browser and come back to Part B, which is the long part: business details, promoters, the authorised signatory, places of business, goods and services, and the document uploads listed in our documents checklist.

It lasts 15 days. If Part B is not submitted in that time, the draft is deleted and Part A has to be done again for a fresh TRN.

Logging in with a TRN

1. Go to gst.gov.in and choose Services → Registration → New Registration.
2. Select Temporary Reference Number (TRN), enter it with the captcha, and proceed.
3. Enter the OTP sent to the mobile number and email given in Part A.
4. Open the draft from My Saved Applications and continue with Part B.

You cannot log in with the TRN through the ordinary username and password screen. Those credentials are created only after the GSTIN is issued, at first login. General portal access is covered on our GST portal page.

After the TRN: the ARN

Submitting Part B with a DSC or EVC generates an ARN, the Application Reference Number, which replaces the TRN as the handle for the application. The ARN is what you track while the officer reviews it, and what you quote in reply to any query. How to read its status is in our ARN status guide, and if you have an ARN but have lost track of the GSTIN it led to, see finding a GSTIN from an ARN.

Temporary ID under Rule 16A

Rule 16A of the CGST Rules allows an officer to assign a temporary identification number to a person who is not registered but is required to make a payment under the Act. A typical case is a business that should have registered and did not: the department determines tax, interest and penalty, and the temporary ID lets the person log in and pay it through the portal.

The temporary ID is an accounting handle for the department. It does not register the person, does not let them issue tax invoices, and does not appear as an active registration when anyone looks it up. If the person has to be registered going forward, that is a separate registration.

Time-bound registrations: casual and non-resident

A casual taxable person — a business making occasional supplies in a state where it has no fixed place of business, such as an exhibitor at a fair — is granted a real GSTIN, but only for the period applied for, up to 90 days, extendable once. It needs an advance deposit of estimated tax. The non-resident taxable person registration for foreign suppliers works the same way. Both are explained in the casual taxable person guide and in types of GST registration.

These GSTINs are genuine and can go on tax invoices while they are valid. After the period ends, the registration is no longer active, and a lookup shows it that way.

None of these lets you charge GST

The one mistake all three meanings share is using a temporary number as if it were a GSTIN. A supplier who prints a TRN or ARN on a bill and adds GST has collected tax without a registration, and the buyer cannot claim credit for it. Our guide on charging GST without registration covers the consequences.

Frequently asked questions