Introduction: Understanding ERP's Building Blocks
You've decided you need ERP. You've chosen between cloud and on-premise deployment. Now comes a question that confuses many Sri Lankan business owners: "Which modules do I actually need?"
When you look at ERP pricing sheets, you see:
- Finance & Accounting
- Inventory Management
- Manufacturing (MRP)
- Sales & CRM
- Purchasing
- HR & Payroll
- Project Management
- E-commerce... and more
The confusion: Do you need all of them? Just some? How do you know?
🧱 Think of ERP Modules Like LEGO Blocks:
- Each module is a functional block (Finance, Inventory, Sales)
- They connect together seamlessly
- You build what your business needs
- Add more blocks as requirements change
But here's what vendors won't tell you upfront: You don't need every module.
This guide breaks down the 7 core ERP modules, explains what each does, and helps you choose which ones your business actually needs.
Finance & Accounting Module
The Heart of Your ERP
Every ERP implementation starts here. The Finance & Accounting module is non-negotiable—it's the central nervous system that connects to every other module.
Core Functions:
General Ledger
Records every transaction, maintains chart of accounts, real-time financial position
Accounts Receivable
Invoicing, payment tracking, aging reports, credit limits
Accounts Payable
Vendor bills, payment scheduling, cash flow forecasting
Financial Reporting
P&L, Balance Sheet, Cash Flow, customizable dashboards
🇱🇰 Sri Lankan Compliance Features:
- VAT: 18% on goods, 8% on services, exempt items, monthly returns
- NBT: 2% Nation Building Tax calculations
- Withholding Tax: 5% WHT on services, 14% on interest
- EPF/ETF Integration: Employer contributions tracked
✅ When You Need Finance Module:
Always. There's no scenario where you implement ERP without Finance & Accounting. It's the foundation.
Inventory Management Module
Know What You Have, Where
If your business sells physical products (even just one SKU), you need inventory management. This module tracks products from purchase to sale, across multiple locations.
Real-time Stock Tracking
Multi-Location Support
Batch/Serial Tracking
Expiry Management
Auto-Reorder Alerts
Barcode Scanning
✅ When You Need Inventory Module:
Sell physical products, hold warehouse stock, multiple locations, need expiry tracking (food/pharma)
Manufacturing (MRP)
From raw materials to finished goods. Plan production, manage resources, track shop floor.
Key Features:
BOM, Work Orders, Shop Floor, Routing, Cost Tracking
✅ Need if: Manufacture products, assemble components, complex production
Sales & CRM
From lead to cash. Manage pipeline, generate quotes, track orders, e-commerce integration.
Key Features:
CRM, Quotations, Sales Orders, Customer Portal, Analytics
✅ Need if: B2B sales, sales team 3+, long sales cycles, online sales
Purchasing
Manage vendors and procurement. RFQs, POs, goods receipt, three-way match.
Key Features:
RFQ, PO, Vendor Management, Goods Receipt, 3-Way Match
✅ Need if: Buy raw materials/products, multiple vendors, approval workflows
HR & Payroll
Manage your people. Attendance, leave, payroll with EPF/ETF/PAYE compliance for Sri Lanka.
Key Features:
Attendance, Leave, Payroll, EPF/ETF (12%+3%), PAYE Tax
✅ Need if: 10+ employees, shift work, complex payroll, statutory compliance
Project Management
Track time, budget & deliverables. For project-based businesses: construction, IT, consulting, agencies.
Key Features: Project Planning, Task Management, Time Tracking, Expense Tracking, Invoicing, Gantt Charts
✅ Need if:
Project-based business, bill by time worked, track profitability
🔄 How Modules Work Together: The Power of Integration
Here's what makes ERP valuable: modules don't work in isolation—they talk to each other.
Example: Complete Sales Order Flow
Sales Module
Customer orders 100 units → System triggers inventory check
Inventory Module
Check stock: Have 100 units? Yes → Reserve. No → Trigger manufacturing
Manufacturing Module
Create work order → Check raw materials → Trigger purchasing if needed
Purchasing Module
Create PO → Goods received → Update inventory → Manufacturing proceeds
Shipping (Inventory)
Pick, pack, ship → Delivery order generated → Inventory decreased
Finance Module
Auto-generate invoice → Payment received → Accounts receivable updated
All of this happens automatically with minimal manual intervention.
That's the power of integration. Without ERP: 10+ manual steps, multiple systems, human error at every stage.
🎯 Choosing Your Modules: Start Small, Grow Over Time
You don't need all modules on Day 1. Here's how to decide:
Module Combinations by Business Type:
Service Business
IT, Consulting, Agencies
Manufacturing
Apparel, Food, Parts
Retail
Single/Multi-Location Stores
Construction
Project-Based Businesses
🚀 Phased Implementation Approach:
Phase 1 (Months 1-3)
Foundation: Finance + Inventory (if product-based)
Phase 2 (Months 4-6)
Growth: Add Sales/CRM or Manufacturing
Phase 3 (Months 7-12)
Optimization: Add HR or Project Mgmt
Benefits: Lower risk, easier training, faster ROI, cash flow friendly
📚 Related Articles
What is ERP? Complete Beginner's Guide
Start with the basics before diving into modules.
Cloud vs On-Premise: Choose Deployment
After choosing modules, decide on deployment model.
10 Signs You've Outgrown Spreadsheets
Confirm you're ready for ERP before selecting modules.
How to Choose the Right ERP System
Once you know your modules, choose the right ERP platform.
Questions about which modules your business needs? Drop a comment below or contact us. We help Sri Lankan businesses choose the right ERP modules for their specific needs.
About ChaosHub: We're Sri Lanka's independent resource for ERP education. We help you understand what you need—not what vendors want to sell you.
Introduction: Understanding ERP's Building Blocks
You've decided you need ERP. You've chosen between cloud and on-premise deployment. Now comes a question that confuses many Sri Lankan business owners: "Which modules do I actually need?"
When you look at ERP pricing sheets, you see:
- Finance & Accounting
- Inventory Management
- Manufacturing (MRP)
- Sales & CRM
- Purchasing
- HR & Payroll
- Project Management
- E-commerce... and more
The confusion: Do you need all of them? Just some? How do you know?
🧱 Think of ERP Modules Like LEGO Blocks:
- Each module is a functional block (Finance, Inventory, Sales)
- They connect together seamlessly
- You build what your business needs
- Add more blocks as requirements change
But here's what vendors won't tell you upfront: You don't need every module.
This guide breaks down the 7 core ERP modules, explains what each does, and helps you choose which ones your business actually needs.
Finance & Accounting Module
The Heart of Your ERP
Every ERP implementation starts here. The Finance & Accounting module is non-negotiable—it's the central nervous system that connects to every other module.
Core Functions:
General Ledger
Records every transaction, maintains chart of accounts, real-time financial position
Accounts Receivable
Invoicing, payment tracking, aging reports, credit limits
Accounts Payable
Vendor bills, payment scheduling, cash flow forecasting
Financial Reporting
P&L, Balance Sheet, Cash Flow, customizable dashboards
🇱🇰 Sri Lankan Compliance Features:
- VAT: 18% on goods, 8% on services, exempt items, monthly returns
- NBT: 2% Nation Building Tax calculations
- Withholding Tax: 5% WHT on services, 14% on interest
- EPF/ETF Integration: Employer contributions tracked
✅ When You Need Finance Module:
Always. There's no scenario where you implement ERP without Finance & Accounting. It's the foundation.
Inventory Management Module
Know What You Have, Where
If your business sells physical products (even just one SKU), you need inventory management. This module tracks products from purchase to sale, across multiple locations.
Real-time Stock Tracking
Multi-Location Support
Batch/Serial Tracking
Expiry Management
Auto-Reorder Alerts
Barcode Scanning
✅ When You Need Inventory Module:
Sell physical products, hold warehouse stock, multiple locations, need expiry tracking (food/pharma)
Manufacturing (MRP)
From raw materials to finished goods. Plan production, manage resources, track shop floor.
Key Features:
BOM, Work Orders, Shop Floor, Routing, Cost Tracking
✅ Need if: Manufacture products, assemble components, complex production
Sales & CRM
From lead to cash. Manage pipeline, generate quotes, track orders, e-commerce integration.
Key Features:
CRM, Quotations, Sales Orders, Customer Portal, Analytics
✅ Need if: B2B sales, sales team 3+, long sales cycles, online sales
Purchasing
Manage vendors and procurement. RFQs, POs, goods receipt, three-way match.
Key Features:
RFQ, PO, Vendor Management, Goods Receipt, 3-Way Match
✅ Need if: Buy raw materials/products, multiple vendors, approval workflows
HR & Payroll
Manage your people. Attendance, leave, payroll with EPF/ETF/PAYE compliance for Sri Lanka.
Key Features:
Attendance, Leave, Payroll, EPF/ETF (12%+3%), PAYE Tax
✅ Need if: 10+ employees, shift work, complex payroll, statutory compliance
Project Management
Track time, budget & deliverables. For project-based businesses: construction, IT, consulting, agencies.
Key Features: Project Planning, Task Management, Time Tracking, Expense Tracking, Invoicing, Gantt Charts
✅ Need if:
Project-based business, bill by time worked, track profitability
🔄 How Modules Work Together: The Power of Integration
Here's what makes ERP valuable: modules don't work in isolation—they talk to each other.
Example: Complete Sales Order Flow
Sales Module
Customer orders 100 units → System triggers inventory check
Inventory Module
Check stock: Have 100 units? Yes → Reserve. No → Trigger manufacturing
Manufacturing Module
Create work order → Check raw materials → Trigger purchasing if needed
Purchasing Module
Create PO → Goods received → Update inventory → Manufacturing proceeds
Shipping (Inventory)
Pick, pack, ship → Delivery order generated → Inventory decreased
Finance Module
Auto-generate invoice → Payment received → Accounts receivable updated
All of this happens automatically with minimal manual intervention.
That's the power of integration. Without ERP: 10+ manual steps, multiple systems, human error at every stage.
🎯 Choosing Your Modules: Start Small, Grow Over Time
You don't need all modules on Day 1. Here's how to decide:
Module Combinations by Business Type:
Service Business
IT, Consulting, Agencies
Manufacturing
Apparel, Food, Parts
Retail
Single/Multi-Location Stores
Construction
Project-Based Businesses
🚀 Phased Implementation Approach:
Phase 1 (Months 1-3)
Foundation: Finance + Inventory (if product-based)
Phase 2 (Months 4-6)
Growth: Add Sales/CRM or Manufacturing
Phase 3 (Months 7-12)
Optimization: Add HR or Project Mgmt
Benefits: Lower risk, easier training, faster ROI, cash flow friendly
📚 Related Articles
What is ERP? Complete Beginner's Guide
Start with the basics before diving into modules.
Cloud vs On-Premise: Choose Deployment
After choosing modules, decide on deployment model.
10 Signs You've Outgrown Spreadsheets
Confirm you're ready for ERP before selecting modules.
How to Choose the Right ERP System
Once you know your modules, choose the right ERP platform.
Questions about which modules your business needs? Drop a comment below or contact us. We help Sri Lankan businesses choose the right ERP modules for their specific needs.
About ChaosHub: We're Sri Lanka's independent resource for ERP education. We help you understand what you need—not what vendors want to sell you.
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