Software cost is rarely just “build time.” A realistic estimate includes discovery, delivery, launch, and ownership. This framework helps you size a project based on risk and complexity rather than guesswork.
Step 1: Define the build type
Pick the closest match:
- Marketing site + lead capture
- Internal tool (ops/back-office)
- Customer portal (auth, roles, data)
- Marketplace (multi-sided, payments)
- Integration-heavy platform (APIs, events, webhooks)
As you move down the list, integration and security effort tends to rise faster than UI effort.
Step 2: Count complexity drivers
Each item increases effort:
- Authentication and roles (RBAC)
- Payments and invoicing
- Multi-language / multi-currency
- Offline support / PWA
- Real-time features (notifications, live updates)
- Reporting and analytics
- Admin tools and audit logs
- Mobile apps (iOS/Android)
Step 3: Inventory integrations
For each integration, specify:
- API type (REST, GraphQL, SOAP, file-based)
- Auth method (OAuth, keys, SSO)
- Rate limits, retries, and error modes
- Webhooks and signature verification
Integrations usually drive the most hidden scope.
Step 4: Choose quality level
Decide up front:
- Testing depth (smoke vs. automated suites)
- Security requirements (PII, PCI, residency)
- Performance targets (p95 latency, throughput)
- Observability (logs, metrics, traces)
Higher quality reduces long-term cost, but needs explicit budget.
Step 5: Add ownership costs
Plan for:
- Hosting and monitoring
- Dependency and security updates
- Bug fixes and minor enhancements
- Support and incident response
Ownership is ongoing; budget it as a recurring line item.
A practical output
Your estimate should include:
- Timeline range with assumptions
- Scope boundaries and non-goals
- Identified risks and mitigation steps
- Milestones tied to business outcomes