Build vs. Buy Calculator
The True Cost of “Internal Tools”CEO/Founder Context: “We can build it in a weekend” is the most expensive sentence in tech. Use this reality check to uncover the hidden costs of maintenance, technical debt, and lost opportunity before you approve an internal build.
1. The “Build” Reality
*Hofstadter’s Law: It always takes longer than you expect.
2. The “Buy” Alternative
3. TCO Comparison (Year 1)
5-Year Cumulative Cost
Book a roadmap audit with a Fractional CPO.
Frequently Asked Questions
What does the Build vs. Buy Calculator measure? +
It compares the first-year and multi-year cost of building an internal tool versus buying a SaaS product. It factors in developer time, a pessimism multiplier, annual maintenance, and subscription cost so you can see the true total cost of ownership.
What is the pessimism multiplier? +
The pessimism multiplier adjusts your original build estimate to reflect how internal tools usually take longer than expected. It is a practical way to account for delays, rework, integrations, edge cases, and shifting requirements.
Why does maintenance matter so much in build vs. buy decisions? +
Internal tools rarely stop costing money after launch. You still need bug fixes, updates, security work, support, and technical debt cleanup. Maintenance is often the hidden cost that makes building far more expensive over time.
When does it make sense to build instead of buy? +
Building makes more sense when the capability is core intellectual property, a real strategic differentiator, or something the market cannot serve well. If the tool is operational plumbing rather than competitive advantage, buying is often the better move.
Does this tool include opportunity cost? +
It highlights the time lost to internal development, but it does not fully quantify what your team could have built instead. In reality, opportunity cost is often the biggest reason buying wins, because roadmap focus has far more value than the spreadsheet shows.
Does this calculator store my assumptions? +
Yes, it saves your latest inputs locally in your browser so you can revisit the comparison later. It does not require an account and it does not send your assumptions to a server by default.