GST can feel like a collection of forms, rates and deadlines. But its basic logic starts with one question: is there a supply? Once you understand that, concepts such as registration, place and time of supply, input tax credit, returns and e-way bills start to connect.
This guide follows the topics and examples in CA Devesh Thakur’s 30 Days GST Challenge, from the fundamentals through the compliance and audit chapters.
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Day 1: What is GST?
Goods and Services Tax (GST) came into effect on 1 July 2017, bringing several earlier indirect taxes into a common framework. It applies to the supply of goods and services. The tax is indirect: businesses generally collect it from customers and pass it on through the supply chain.
The central concept is supply. GST is considered when a transaction is treated as a supply under the law. Some transactions between branches can also count, even when there is no separate payment between them. That is why a transfer of stock between branches in different states may have GST consequences.
GST registration is state-wise rather than a single central registration for every business location. The main types of GST discussed in the video are:
- CGST: Central Goods and Services Tax
- SGST: State Goods and Services Tax
- UTGST: Union Territory Goods and Services Tax
- IGST: Integrated Goods and Services Tax
GST is destination-based. The tax revenue is associated with the place where goods or services are consumed. In a supply chain, eligible input tax credit allows tax already paid on purchases to be set off against tax due on sales. The final consumer bears the tax after the successive value additions.
The video illustrates this with goods moving from a manufacturer in Uttar Pradesh to a consumer in Maharashtra. A manufacturer sells goods for ₹100 and pays ₹18 GST at 18%. A wholesaler adds ₹50 of value and sells for ₹150, creating ₹27 of output tax. After credit for the ₹18 already paid, the wholesaler’s net tax is ₹9. A retailer then sells for ₹200, creating ₹36 of output tax; after credit for ₹27, the retailer also pays ₹9. The consumer pays ₹236, including ₹36 GST. The example shows how tax is charged at each stage while credit offsets tax paid earlier.
Day 2: Registration, supply and the basic tax structure
The video introduces turnover thresholds for registration: ₹40 lakh for goods and ₹20 lakh for services, with lower thresholds of ₹20 lakh and ₹10 lakh respectively for special category states. It also notes that other specified reasons may require registration regardless of these thresholds.
Supply is examined through three schedules:
- Schedule I covers certain activities treated as supply even without consideration.
- Schedule II helps classify activities as supplies of goods or services.
- Schedule III lists activities treated as neither a supply of goods nor a supply of services.
For a seller, outward supplies create output tax liability. A buyer may pay input tax and, where eligible, use input tax credit to reduce output liability.
The distinction between intra-state and inter-state supply determines which tax applies. When the supplier and place of supply are in the same state, the transaction is generally intra-state and CGST with SGST applies. For a Union Territory, CGST with UTGST applies. When the supplier and place of supply are in different states or Union Territories, IGST applies.
The taxable value is the value on which GST is calculated. The video explains that charges such as commission and packaging may be added, while a qualifying trade discount may be deducted. It then uses the 5%, 12%, 18%, 28% and 0% rates as examples. For an intra-state supply, the applicable rate is split between the relevant central and state or Union Territory components; for an inter-state supply, IGST is charged at the applicable rate.
Day 3: What counts as a supply?
The video breaks the supply concept into three parts. Section 7 of the CGST Act is the starting point for deciding whether an activity is a supply.
The first part covers transactions made for consideration in the course or furtherance of business. The examples named include sale, transfer, barter, exchange, licence, rental, lease and disposal. Consideration need not always be monetary; something received in return may also matter. A payment received now for a service to be delivered later is discussed as a supply-related situation.
The video also explains that supplies between branches or distinct persons can be treated as supplies even without consideration. Activities by clubs, associations or trusts for their members are also discussed in the context of the statutory supply rules.
The schedules matter because some activities may be treated as supply even without consideration, some activities are classified as goods or services, and others are kept outside the scope of supply. The practical lesson is to classify the transaction before calculating tax.
Day 4: Levy and collection
The levy and collection discussion builds on the supply concept. Before deciding how much GST is due, identify the nature of the supply, the applicable tax type and who is responsible for paying it.
For an intra-state transaction, CGST and SGST or UTGST are relevant. For an inter-state transaction, IGST applies. The video also introduces reverse charge, under which the recipient rather than the supplier is responsible for paying GST in specified cases. The later days return to forward charge and reverse charge in more detail.
Day 5: Place of supply for goods
Place of supply helps determine whether a transaction is intra-state or inter-state and, in turn, whether CGST with SGST or UTGST applies, or whether IGST applies.
For goods involving movement, the place of supply is linked to where the movement ends for delivery to the recipient. The video’s examples of goods moving between Delhi, Haryana and other locations illustrate why a seller must look beyond the billing address and consider where the goods are actually being sent.
The chapter also covers situations where goods are supplied without movement and other specific goods-related cases. These rules help establish the destination for tax purposes.
Day 6: Place of supply for services
Services require a separate place-of-supply analysis. The relevant location can depend on who the supplier and recipient are, whether the recipient is registered, and the nature of the service.
The video discusses general rules as well as examples where a specific rule applies. Its central point is that the place of supply for services cannot be chosen only by looking at the supplier’s office or the invoice address. The transaction must be examined under the applicable service rule.
Day 7: Time of supply of goods
Time of supply determines when GST liability arises. For goods, the video explains the relevant dates by comparing the invoice, delivery or removal of goods, and payment. The applicable time is identified by applying the rule discussed in the video to the facts of the transaction.
This makes accurate dates important. Businesses should retain the invoice and delivery records so they can identify the correct tax period.
Day 8: Time of supply of services
The time-of-supply rules for services are explained separately because the relevant dates may differ from those for goods. The video considers invoice and payment timing and the circumstances in which an invoice is issued within or beyond the prescribed period.
The practical point is to determine the time of supply from the actual sequence of service delivery, invoicing and payment rather than assuming that every service transaction follows the same timeline.
Day 9: Value of supply
GST is calculated on the taxable value of the supply. The video discusses transaction value and adjustments that may affect it, including costs or charges connected with the supply and discounts.
In the earlier example, commission and packaging charges are added to the value, while a qualifying trade discount is deducted. Once the taxable value is determined, the applicable GST rate is applied.
Day 10: Forward charge and reverse charge
Under the usual forward-charge mechanism, the supplier charges GST and pays it to the government. Under reverse charge, the recipient is liable to pay GST in specified situations.
The video uses a housekeeping agency example in its recap: where the relevant conditions for reverse charge apply, the recipient may need to pay the tax. The key is not to assume that every purchase from an unregistered supplier automatically falls under reverse charge; the transaction must be checked against the applicable rules discussed in the video.
Day 11: Introduction to Input Tax Credit
Input tax credit (ITC) is the credit for eligible GST paid on business purchases. It can be used to reduce output tax liability, which is why the wholesaler and retailer in the opening example pay tax only on their respective value additions after credit.
ITC is not simply a credit for every tax amount appearing on a bill. The buyer must check whether the purchase and the relevant documents meet the requirements for claiming it.
Day 12: Conditions for claiming ITC
The video explains that ITC is subject to conditions. The buyer must review the invoice and the supply, confirm that the goods or services are received, and consider whether the tax has been paid and the required return conditions have been met.
The video stresses business use and taxable supplies. Personal expenses do not qualify for ITC under the principle highlighted in the recap. Records and supporting documents are essential to substantiate a claim.
Day 13: Set-off of ITC
Once eligible ITC is determined, it must be used in the order prescribed for the relevant tax heads. The video introduces the set-off framework and stresses that credit is not freely interchangeable in every situation.
Businesses should identify whether the credit relates to IGST, CGST, SGST or UTGST and apply it in accordance with the applicable utilisation rules.
Day 14: Cases where ITC is denied
Some credits are not available even when GST has been paid. The video devotes a separate day to cases where 100% ITC is denied, reinforcing that payment of tax by itself does not make a credit claim valid.
This topic connects with the later discussion of blocked credits under Section 17(5). A business should identify the nature and purpose of each expense before treating the GST as credit.
Day 15: Job work under GST
Job work involves sending goods to another person for a process or treatment. The video includes job work within the 30-day GST learning plan and later lists goods sent to job workers among the records a business should maintain.
The essential compliance point from the video is to track the goods sent, their movement and their return. Keeping a job-work register helps support the business’s GST records.
Day 16: Composition Scheme
The composition scheme is covered as a separate GST topic. The video places it within the sequence of core concepts and compliance matters, helping viewers distinguish the scheme from the regular GST framework.
A business considering the scheme needs to understand whether it is eligible and how its tax and return obligations differ. The video’s broader message is to identify the correct GST treatment before filing.
Day 17: GST registration
Registration is discussed first through turnover thresholds and other specified registration reasons, then revisited as a full chapter. The video emphasizes that registration is state-wise and that a business’s circumstances matter when determining whether registration is required.
Because a business may operate in more than one state, its registration position should be considered location by location. The video’s example of stock transfers between branches also shows why registrations in different states can affect how internal transfers are treated.
Day 18: GST documents
GST compliance depends on using the appropriate documents for the transaction. The video discusses tax invoices and bills of supply in the context of return and e-way bill procedures.
For movement of goods, the documentation needs to align with the actual transaction, including the seller, buyer, goods, value and tax details. Correct documents help support return reporting and movement of goods.
Day 19: GSTR-1: outward supplies
GSTR-1 is the outward supplies return covered in the video. It reports details of sales and other outward supplies. The chapter links this return to the underlying invoices and transaction records.
Accurate reporting matters because outward supply details feed into the broader GST compliance process. Businesses should reconcile the information they report with their books and invoices.
Day 20: GSTR-3B: summary return
GSTR-3B is discussed as the summary return. The video connects it to reporting output tax, input tax credit and the tax payable for the period.
The underlying figures should agree with the business’s sales, purchase and tax records. Reconciling the summary return with detailed outward supply information and ITC records helps identify errors before filing.
Day 21: E-commerce under GST
The e-commerce chapter explains the role of online platforms in GST. In the closing recap, the video notes that platforms such as Amazon or Flipkart collect tax at source in the relevant cases and deposit it with the government. The seller then claims the corresponding credit through the applicable process.
For sellers using e-commerce platforms, the platform statements and the seller’s own sales records need to be reviewed together. The goal is to ensure that the reported sales and tax credits correspond to the actual transactions.
Day 22: GSTR-10: final return
GSTR-10 is introduced as the final return chapter. It relates to the closure of GST registration and is distinct from the periodic returns discussed earlier.
The video’s sequence highlights that cancelling a registration does not mean the final compliance step can be ignored. The applicable final-return requirement should be considered as part of the exit process.
Day 23: Blocked credit under Section 17(5)
Section 17(5) is specifically covered as blocked credit. It identifies categories where ITC may be restricted, even if the purchase is connected with the business.
This chapter links back to the broader ITC lessons: check the nature and use of the expense, identify any restriction and keep the reasoning and supporting records clear.
Day 24: GSTR-9: annual return
GSTR-9 is the annual return chapter in the challenge. It brings together information from the financial year, including outward supplies, tax liability and ITC.
A useful preparation approach from the video’s broader compliance themes is to keep periodic returns and books aligned throughout the year. That makes annual reporting and reconciliation easier.
Day 25: Interest on late payment
The video includes interest on late payment as a dedicated topic. It is part of understanding the cost of not paying GST on time and the importance of monitoring liability and payment dates.
Businesses should track when tax becomes payable and whether the corresponding payment has been made. Keeping the time-of-supply and payment records organised helps with this review.
Day 26: Types of assessment
The assessment chapter introduces different ways GST liability and compliance may be examined. It prepares viewers for the later discussion of audits and the distinction between a review of records and a demand proceeding.
The video’s recap of audits makes a related point: an audit finding does not automatically mean a demand has been raised. A demand arises through the relevant statutory process.
Day 27: E-way bill
An e-way bill supports the movement of goods. The video describes the practical information entered while generating one, including the document type and number, transaction type, seller and buyer details, item description, HSN code, quantity, unit, taxable value and GST rate.
For a Bill To–Ship To transaction, the billing recipient and the delivery destination may differ. The e-way bill process also includes transporter details, mode of transport and vehicle information. The video explains that the transporter ID can populate the transporter’s name and help calculate an approximate distance based on the PIN codes.
The video states that an e-way bill is generally required for movement of goods where the value exceeds ₹50,000, including movement between states, and emphasizes that incorrect details can lead to delay or penalty risk. Check the transaction and applicable requirements before generating the document.
Day 28: Accounts, records and audit
GST records should be maintained at the principal place of business. Where a business has additional places of business, the video says records should also be maintained at those locations. It also discusses maintaining records activity-wise, such as separately for manufacturing, trading and services.
The records mentioned include:
- Inward supply and ITC records
- Outward supply and tax liability records
- Goods sent for job work
- Stock records
- Related-party transactions
- Filed returns
The video describes an audit review of inward supplies as including checks on ITC eligibility, reverse-charge payments, purchase invoices, proportional credit, short receipts, destroyed or rejected goods, credit notes and adjustments, Rules 42 and 43, and blocked credits.
It also discusses GSTR-9C and the reconciliation of audited financial statements with annual GST information. Check current requirements before relying on thresholds or filing obligations.
Day 29: Types of audit
The video explains audit as a review of the correctness of turnover, taxes paid, refund claims, ITC availed and compliance with the Act and Rules.
It covers two forms of audit:
- Audit by tax authorities: Conducted by the Commissioner or an authorised officer for one or more financial years. The video discusses notice, the place of audit and the period for completing it, including the possibility of an extension.
- Special audit: Considered during scrutiny, inquiry, investigation or another proceeding where the declared value or ITC is in question. The video explains that an officer above the rank of Assistant Commissioner may order it and assign it to a Chartered Accountant or Cost Accountant.
The chapter names Forms GST ADT-1, ADT-3 and ADT-4 in connection with audit notices, special audit reporting and audit findings. It also clarifies that an audit does not itself raise a demand. A demand may follow if the relevant proceedings are initiated, a show-cause notice is issued and the taxpayer receives an opportunity to be heard.
Day 30 bonus: Revising the key GST concepts
The challenge ends with a connected example featuring Ramesh, a Delhi dry-fruit supplier:
- When Ramesh sells to a customer in Delhi, the supplier and place of supply are in the same state, so CGST and SGST apply.
- When he receives an order from Haryana, the supplier and place of supply are in different states, so the transaction is inter-state and IGST applies.
- When he opens a store in Chandigarh, a Union Territory, CGST and UTGST apply to the relevant intra-UT supply.
- When goods move from one state branch to another, the transfer may be treated as a supply because GST registration is state-based.
- When he hires an unregistered housekeeping agency, the reverse-charge position must be considered where the applicable rules require it.
- ITC is linked to business use and taxable supplies; personal expenses do not qualify under the principle explained in the video.
- For goods, the time of supply is identified by comparing the invoice, delivery and payment dates under the rule discussed in the video.
- An e-commerce platform may collect TCS and deposit it with the government, with the seller claiming the corresponding credit through the applicable process.
- For an export of goods, the goods must physically leave India for the export treatment described in the recap.
- If Ramesh receives online branding consultancy from China, the video says IGST under reverse charge must be considered.
The story brings together the main ideas from the series: classify the supply, determine its place and time, calculate its taxable value, identify the responsible person, review ITC, report the transaction and retain the supporting records.
Conclusion
The 30 Days GST Challenge moves from the foundation of GST to practical compliance. Its recurring lesson is to examine each transaction before filing: determine whether it is a supply, identify where and when it takes place, calculate the taxable value, apply the correct tax mechanism, check ITC eligibility and preserve the supporting documents.
That sequence gives students, business owners and accounting professionals a structured way to approach GST concepts and returns. For any live transaction, verify the current legal provisions and applicable portal requirements before acting.
