Introduction
Generating a GST invoice for a mobile repair shop is notoriously complex. Unlike a retail store that simply slaps 18% GST onto a finished good, a mobile repair job is often a "composite supply." It involves both the sale of goods (spare parts like screens or batteries) and the provision of services (the technician's labor).
If your turnover exceeds the ₹20 Lakh threshold (₹10 Lakh for special category states) or you are supplying B2B services via corporate contracts, GST registration and compliant billing are mandatory.
Here is a definitive guide to handling GST billing for mobile repair shops in India.
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The Difference Between HSN and SAC Codes
To generate a legal GST invoice, you must correctly classify what you are selling using specific codes:
HSN Codes (Harmonized System of Nomenclature) These are used for physical goods. If you sell a mobile phone, a charging cable, or use a spare battery in a repair, these items fall under HSN codes. Rates vary (e.g., 18% for mobile phones and most parts).
SAC Codes (Servicing Accounting Code) These are used for services. The labor your technician provides to install that battery falls under an SAC code. The standard GST rate for electronics repair services (SAC 9987) is 18%.
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Method 1: Split Invoicing (The Safe Way)
The most transparent way to bill a customer—especially a B2B corporate customer seeking Input Tax Credit (ITC)—is to explicitly itemize the goods and the labor on the same invoice.
Example Invoice Breakdown: 1. Item: Replacement LCD Screen for iPhone 13 * HSN: 8517 (Parts of telephone sets) * Value: ₹8,000 * GST: 18% (₹1,440) 2. Item: Repair Service / Labor Charge * SAC: 998713 (Maintenance and repair of telecommunication equipment) * Value: ₹2,000 * GST: 18% (₹360)
Total Invoice Value: ₹12,000 (inclusive of ₹1,800 total GST).
*Note: If the customer is in your state, split the 18% into 9% CGST + 9% SGST. If they are in a different state, apply 18% IGST.*
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Method 2: Composite Supply Invoicing
Under GST law, if a supply involves both goods and services that are naturally bundled and supplied in conjunction with each other, it is a "composite supply." The GST rate of the "principal supply" dictates the rate for the entire invoice.
In mobile repair, the primary reason the customer came to you was to get their phone fixed (the service). However, the value of the spare part (the screen) often exceeds the value of the labor.
Because of this ambiguity, tax experts highly recommend Method 1 (Split Invoicing) to avoid disputes during a tax audit. It provides absolute clarity on your margins and exact tax liabilities.
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Automating the Headache
Doing this manually on a generic billing pad or struggling with basic accounting software is a massive waste of your time.
When using a specialized OS like MobiBix, the complexity vanishes: 1. You add the replacement screen to the Job Card. MobiBix knows it's an inventory item (HSN) and calculates the tax. 2. You add a £2,000 labor fee. MobiBix knows it's a service (SAC) and calculates the tax. 3. The software automatically applies CGST/SGST based on the customer's state code vs your state code. 4. You click 'Print' or 'Send via WhatsApp', and a perfectly formatted, legal PDF is generated instantly.
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Conclusion
Failing to comply with proper GST HSN/SAC breakdowns can result in steep fines and the rejection of Input Tax Credit for your B2B clients. Don't risk your license by taking shortcuts with generic software.
*MobiBix handles all Indian GST complexities natively, designed specifically for the split-billing needs of repair shops. [Try it free for 14 days](/pricing).*