Registration: formula sheet

Key formulas

Default rule (Section 22)

Register if aggregate turnover > threshold limit

Services-only suppliers: ₹20 lakh (₹10 lakh in special category States, subject to the notified list of States). Goods suppliers: ₹40 lakh in most States (₹20 lakh in special category States, subject to the notified list). Lower thresholds apply in some States. This default does not help persons caught by Section 24.

Override rule (Section 24)

Listed person → registration compulsory, irrespective of turnover

Applies even if turnover is nil or below the threshold. Always check the category first. Inter-State supplier is no longer a listed category.

Inter-State supply of goods

Inter-State taxable supply of goods + aggregate turnover ≤ goods threshold + no other Section 24 trigger → registration not required

Section 24(i) was omitted from 1 October 2023, so Section 22 and the notified goods threshold apply: ₹40 lakh, or ₹20 lakh in special category States (subject to the notified list). Above the threshold, or if another Section 24 trigger applies, registration is compulsory.

Inter-State supply of services

Inter-State taxable services + aggregate turnover ≤ services threshold + no other Section 24 trigger → registration not required

Section 22 and the notified threshold govern this case: ₹20 lakh, or ₹10 lakh for special category States (subject to the notified list of States). Above that limit, or if another Section 24 trigger applies, registration is compulsory.

Casual and non-resident taxable persons

Apply at least 5 days before starting business; registration valid for the period in the application or 90 days, whichever is earlier; extendable by a further period not exceeding 90 days

An advance deposit of estimated tax liability is required. The extension is allowed by the proper officer on application made before the registration expires.

Reverse charge recipients

Person liable to pay tax under Section 9(3) or 9(4) → must register

Check whether a notification exempts the specific case before concluding.

Time limit for others

Apply within 30 days of becoming liable

The 30-day limit applies to ordinary persons liable under Section 22 or 24, not to casual or non-resident taxable persons.

Casual taxable person: when to register

Apply at least 5 days before commencing business; the advance deposit of estimated tax is made at the time of application

No turnover threshold applies. The application is made at least 5 days before the business starts in the State, and the advance deposit of estimated tax is made when the application is submitted (section 27).

CTP/NRTP validity

Validity = period stated in application or 90 days, whichever is earlier

Can be extended by a further period not exceeding 90 days, on application before expiry, after a further deposit.

Advance deposit

Deposit = estimated tax liability for the whole period of registration

It is paid into the electronic cash ledger at the time of submitting the application. For an extension, a further deposit of estimated liability for the extended period is needed.

Returns for CTP/NRTP

CTP: GSTR-1 and GSTR-3B (as for regular taxpayers). NRTP: GSTR-5

A CTP files GSTR-1 and GSTR-3B like a regular taxpayer. An NRTP files GSTR-5 by the 20th of the following month or within 7 days after the registration expires, whichever is earlier.

NRTP application

Apply at least 5 days before commencing business; the advance deposit of estimated tax is made at the time of application

The NRTP applies with its PAN, or with a passport or other prescribed document if it is a foreign national with no PAN. An Indian mobile number and email are needed for OTP verification.

ISD registration

A person acting as ISD needs a separate ISD registration for the ISD office, under the same PAN

The ISD distributes credit only to recipients having the same PAN. From 1 April 2025 (as amended by the Finance Act, 2024), the ISD mechanism is mandatory for distributing input tax credit on common input services. The entity holds a regular registration for its own outward supplies.

Tax deductor and collector

Registration required without regard to turnover threshold: section 24(vi) for deductors, section 24(x) for e-commerce operators liable to collect tax

Under TDS (section 51), specified persons such as government departments, local authorities and governmental agencies deduct, along with other notified persons. Only e-commerce operators liable to collect tax under section 52 register as tax collectors. The registration is for deducting or collecting tax and is separate from any registration for own supplies.

OIDAR supplier from outside India

Registration is mandatory if supplying OIDAR services to non-taxable online recipients in India; no threshold

A non-taxable online recipient (section 2(16) of the IGST Act) is a government, local authority, governmental authority, individual or other person in India who is not registered and who receives OIDAR services for a purpose other than commerce, industry or any other business or profession. A simplified registration procedure applies. A non-resident OIDAR supplier registers under the simplified procedure (OIDAR registration) and pays the tax. A representative may be appointed in India for the purpose of paying the tax on his behalf.

Time limit for applying

Apply within 30 days of becoming liable; casual taxable / non-resident taxable person: at least 5 days before commencement

Applies to regular persons liable under the threshold or other compulsory rules.

Effective date of registration

Applied within 30 days → date of becoming liable; applied later → date of grant

For voluntary registration the effective date is the date of grant.

Application form and parts

REG-01: Part A (PAN, mobile, email → TRN) + Part B (details + documents)

TRN is valid only for a short window (15 days), so complete Part B quickly.

Officer action on REG-01

Officer must act within 3 working days (Aadhaar-authenticated) or 7 working days (others) of the application → grant (REG-06) or deficiency notice (REG-03) → reply REG-04 within 7 working days of service of notice → officer's order within 7 working days of reply

Applicants who are not Aadhaar-authenticated also face a longer route involving biometric appearance; check the latest rules for that part of the timeline.

Deemed registration

No REG-03 notice and no order within 3 working days (Aadhaar-authenticated) or 7 working days (others) of the application → registration deemed approved (Section 25(7), Rule 9(5))

Operates at the application stage, and the period is the same as the officer's period to act. Do not state a blanket deemed approval after the REG-04 reply; there the officer must pass an order within 7 working days.

Forms to remember

REG-01 application | REG-03 notice | REG-04 reply | REG-05 rejection | REG-06 certificate

Exams often ask which form does what.

GSTIN structure

GSTIN (15) = State code (2) + PAN (10) + Entity number (1) + 'Z' (1) + Check digit (1)

Same PAN, different State → different State code and different GSTIN.

Amendment timeline

Inform proper officer of change in particulars within 15 days of the change (Section 28)

Core changes need officer approval. A change in PAN needs a fresh registration, not an amendment.

Cancellation by officer: procedure

Show-cause notice (REG-17) → reply within 7 working days (REG-18) → order within 30 days of reply (REG-19)

A hearing opportunity is mandatory. If proceedings are dropped, the officer passes an order in REG-20.

Revocation time limit

Apply within 30 days of service of cancellation order; extendable by 30 days (Additional/Joint Commissioner) and a further 30 days (Commissioner), only if satisfied there is sufficient cause

Only for cancellation by the officer on his own motion. Form REG-21; officer decides within 30 days. No extension is available without sufficient cause.

ITC payable on cancellation

Higher of (ITC on stock and capital goods) or (output tax on those goods)

Applies to inputs in stock, inputs in semi-finished or finished goods, and capital goods or plant and machinery, on the day immediately preceding the date of cancellation. Paid by debit to the electronic credit or cash ledger. The Section 29(5) payment does not apply to composition taxpayers, who pay under Section 18(4) instead.

Capital goods ITC reduction

ITC remaining = ITC taken × (100 − 5 × number of quarters) ÷ 100

Count each quarter or part of a quarter from the invoice date to the cancellation date. Compare with tax on the transaction value of the asset and pay the higher.

Final return

GSTR-10 within 3 months of the date of cancellation or the date of the cancellation order, whichever is later

Not required from ISDs, non-resident taxable persons and persons deducting TDS or collecting TCS. Composition persons must file it.

Quick revision

• Registration is under the CGST Act, 2017, and is PAN-based but State-wise: one registration per State for each PAN, unless an exception applies.
• Aggregate turnover covers all supplies under the same PAN, including exempt supplies, exports and inter-State supplies. It excludes taxes and inward supplies on reverse charge.
• Registration is required once aggregate turnover exceeds the threshold. Learn the limits for goods and services, and the lower limits for special category States.
• An ordinary person must apply within 30 days from the date on which they become liable to registration. Casual and non-resident taxable persons must apply at least 5 days before starting business.
• Compulsory categories (no threshold) include persons making inter-State supplies, casual taxable persons, non-resident taxable persons, reverse charge payers, ISD, persons required to deduct tax at source under Section 51, e-commerce operators who are required to collect tax under Section 52, suppliers who supply through such e-commerce operators, and persons outside India supplying online information and database access or retrieval (OIDAR) services to a non-taxable online recipient. Some of these are subject to notified exemptions. Inter-State supply of goods requires compulsory registration under Section 24, with only narrow notified exceptions, such as specified handicraft suppliers below the notified limit. The threshold does not otherwise help here. Inter-State supply of taxable services by a person whose aggregate turnover is up to the threshold is exempted from compulsory registration by notification. A person making only supplies on which the entire tax is payable by the recipient under reverse charge is also exempted from registration by notification. Registration for inward reverse charge supplies under Section 9(4) applies only in specified notified cases. Certain small suppliers of specified goods through e-commerce operators are exempted by notification too. Check the current notifications.
• The registration of a casual or non-resident taxable person is valid for the period specified in the application or 90 days from the effective date, whichever is earlier. The proper officer may extend it by a further period not exceeding 90 days, on an application filed before the registration expires.
• Casual and non-resident taxable persons must make an advance deposit of estimated tax liability before registration is granted.
• Voluntary registration is allowed even below the threshold. Once registered, all the obligations of a registered person apply.
• Amendment of core fields needs the officer's approval. Core fields include the legal name of the business, the principal and additional places of business, and, for example, partners or directors. Non-core changes are approved automatically. A change of State is not an amendment. Registration is State-wise, so you need a fresh registration in the new State.
• Cancellation can be applied for by the taxpayer or ordered by the officer on specified grounds.
• Revocation must be applied for within 30 days from the date of service of the cancellation order, not the date of the order. The officer can reject it only through a reasoned order.

Common mistakes

• Saying every inter-State supplier must register whatever the turnover. Fix: Treat inter-State supply as a Section 22 case. Apply the threshold, then check for other Section 24 triggers.
• Using the services limit for a goods supplier, or the goods limit for a services supplier. Fix: Goods: ₹40 lakh (₹20 lakh in special category States, subject to the notified list). Services: ₹20 lakh (₹10 lakh in special category States, subject to the notified list). Identify the supply first.
• Applying the normal turnover threshold to a CTP or NRTP. Fix: Remember that these categories must register regardless of turnover, before they start the supply.
• Confusing CTP with NRTP. Fix: Ask where the person is based. Outside India means NRTP. A person in India with no fixed place of business or residence in that State means CTP.
• Counting the 30-day limit from the date of the first sale or from the start of the year. Fix: Count 30 days from the date on which the person becomes liable to register, not from any other date.
• Saying registration is effective from the date of application. Fix: If applied within 30 days of liability, the effective date is the liability date. If applied later, it is the date of grant.
• Saying revocation is available after a taxpayer's own cancellation application. Fix: Revocation applies only where the proper officer cancelled on his own motion. If you applied, you need fresh registration.
• Mixing up the 15-day, 30-day and 6-month periods. Fix: Tie each number to one event: 15 days to report changes, 30 days to seek revocation, 6 months of non-filing for cancellation of a regular person.

Exam tips

• Start every answer with the Section 24 category, not the threshold. The examiner looks for the override logic.
• For inter-State questions, do not say registration is compulsory just because the supply is inter-State. Section 24(i) is omitted from 1 October 2023. Apply the Section 22 threshold and test the other Section 24 triggers.
• Learn the 5-day and 30-day timelines as a pair, and the 90-day validity for casual and non-resident persons.
• In MCQs, check the State type and the nature of the supply (goods or services) before choosing, as options often differ only in the limit.
• Do not quote notification numbers unless you are certain. State the rule in words and conclude.
• Write the definition first, then apply it to the facts. Examiners award marks for the category and the conclusion.
• In a comparison question, use a point-by-point list with the same headings for both persons.
• Always mention the advance deposit and the 90-day validity for CTP and NRTP when asked about registration.