Deconstructor of Fun
Build vs. Buy Calculator

What does building your own
tooling actually cost?

Most companies underestimate by 3–5x. Adjust the inputs to reflect your team and your vendor quote. The real number includes everything your current budget probably ignores.

Your Company
Engineers assigned 4
Developers diverted from product work to build and maintain the tool
Other project headcount 1
PMs, UI/UX designers, QA — supporting roles pulled onto the internal build
Engineer annual salary $110K base → $138K loaded
Base salary. A 25% employer side cost (social security, health, pension, equipment) is added automatically — shown as the fully loaded figure.
Other headcount annual salary $80K base → $100K loaded
Base salary for PMs, designers, QA. 25% employer side cost added automatically.
Estimated build time 12 mo
Time from kickoff to production-ready deployment
Evaluation period 3 yr
Total cost of ownership window for comparison
Third Party Solution
Integration cost one-off $10K
Engineering and setup time to integrate, configure, and launch
Annual licensing fee per year $60K
Recurring annual cost — enters the comparison across the evaluation period
Projected Savings Over 3 Years
$1.3M
estimated total savings vs. building internally
87%
lower TCO
Build Internally
$1.5M
Third Party Solution
$190K
Build Internally — breakdown
Initial build
$440K
Maintenance (20%/yr)
$330K
Evolution & new features
$198K
Knowledge retention risk
$44K
Opportunity cost
$528K
Third Party Solution — breakdown
Integration one-off
$10K
Licensing annual
$180K

Every month your team spends building tooling that already exists is a month they don't spend building what makes your product better.

Initial build: (Engineers × engineer salary + other headcount × other salary) × 1.25 (employer side costs) × (build months ÷ 12).

Maintenance: 20% of initial build cost per year across the full evaluation period — consistent with the industry benchmark of 15–25% annual maintenance documented in IEEE and Gartner research.

Evolution & new features: 15% of initial build per year. Tooling doesn't stay static; requirements shift and the internal team carries the cost.

Knowledge retention risk: 10% of year-one total salary cost, applied once. Models the real cost when the people who built the tool leave.

Opportunity cost: Total annual team cost × remaining years after build completes — time spent on maintenance instead of core product work.

Third party integration: One-time cost set by the slider. Paid once.

Third party licensing: Annual fee × evaluation period. Total = integration + (annual fee × years).