# Estimates & budget – Go Projects

> Estimating effort, planning buffers, cost over the lifetime.

- [Custom Software Development Cost: A Realistic Budget](https://go-projects.de/en/estimates-and-budget/custom-software-development-cost/): Custom software development cost equals estimated hours multiplied by the hourly rate, plus maintenance over the system's life. A 300-hour internal tool at $100 an hour costs about $30,000; an integrated business application can pass $200,000. Robert Glass puts maintenance at 40 to 80 percent of lifetime software cost, so budget for years of upkeep, not just the build.
- [Software Estimation Techniques: Methods and a PERT Example](https://go-projects.de/en/estimates-and-budget/software-estimation-techniques/): The most practical software estimation technique for most teams is a bottom-up three-point estimate: break the work into packages, give each an optimistic, most likely and pessimistic value, and apply PERT, (O + 4M + P) / 6. Combine the spread across packages and report a range with a probability, such as 47 to 53 days, 80 percent under 51.
- [Story Points Estimation: Planning Poker and Velocity](https://go-projects.de/en/estimates-and-budget/story-points-estimation/): Story points estimation is relative, not hourly. The team picks a small, well-understood reference story as 2 or 3 points and sizes new stories against it. In Planning Poker everyone reveals a Fibonacci card at once and outliers explain their view. Past sprint velocity then turns the remaining backlog into a forecast range.
- [Fixed Price vs Time and Materials: Which Contract Fits?](https://go-projects.de/en/estimates-and-budget/fixed-price-vs-time-and-materials/): Choose a fixed price when scope is stable and precisely specified: the vendor carries the cost risk but charges a premium for it. Choose time and materials when requirements will evolve: you pay actual effort and control scope yourself. A common middle ground is time and materials with a not-to-exceed ceiling and committed must-have scope.

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