How to Budget for a Business Software Project

Why software budgeting is hard

Software projects don't have predictable input costs like construction. You can't measure software in square metres or count the bricks. The cost depends on complexity, which is hard to assess until you understand the problem in detail.

That said, with enough scoping done upfront, budgets can be reasonably accurate. The projects that blow out aren't the ones that were scoped properly. They're the ones where someone made up a number and hoped for the best.

What drives cost

1. Complexity of business logic: Simple CRUD operations are cheap. Complex rules, calculations, approval workflows, and conditional logic are expensive.
2. Number of integrations: Every system you connect adds development time, testing complexity, and ongoing maintenance.
3. User interface requirements: A basic internal tool is cheaper than a polished customer-facing application.
4. Data migration: Moving data from an old system to a new one is almost always harder than expected.
5. Security and compliance: Healthcare, finance, and government projects have additional requirements that add cost.
6. Number of user types: Each user role with different permissions and workflows adds UI screens and backend logic.

Typical Australian ranges

• Simple internal tool (5-10 screens, 1-2 integrations): $30K-$70K
• Business application (15-30 screens, multiple integrations): $80K-$200K
• Complex platform (multiple user types, extensive integrations): $200K-$500K+
• Integration project (connecting 2-5 systems): $15K-$60K
• AI/RAG system (knowledge base, chatbot, document processing): $20K-$80K
• Dashboard/reporting (data pipeline + visualisation): $15K-$50K

Pricing models explained

Fixed price: You agree a price upfront. Developer absorbs the risk of going over. This means they'll pad the quote to cover that risk, typically 20-30% higher than the same scope on time-and-materials.

Time and materials: You pay for actual hours worked. More flexible, often cheaper overall, but requires trust and regular check-ins to prevent runaway spending.

Capped time-and-materials: Time and materials with a maximum spend limit. Gives you flexibility and cost protection. This is usually the best model for medium complexity projects.

Retainer: Ongoing monthly allocation of hours for maintenance, enhancements, and support. Good for post-launch ongoing work.

Hidden costs to plan for

• Hosting and infrastructure: $50-$500/month depending on scale and complexity
• Ongoing maintenance: 15-25% of initial build cost annually (bug fixes, security patches, dependency updates)
• Third-party services: API fees, email services, payment processing, mapping services
• Training: Time and cost to train staff on the new system
• Change management: Resistance to new systems is real and needs to be planned for
• Data migration: Often underestimated by 50-100%

Budgeting framework

1. Get a ballpark: Based on typical ranges above, estimate where your project sits
2. Add 15-20% contingency: For scope evolution and unknowns
3. Add first-year maintenance: Budget for hosting + 15% of build cost for the first year
4. Include discovery: If you haven't scoped yet, add $5K-$15K for a proper discovery phase
5. Plan for phase 2: Most projects have a phase 2. Knowing that upfront helps with budgeting