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Build vs Buy Calculator

Use this build vs buy calculator to compare internal build cost with vendor purchase cost before committing team time or budget.

Planning estimate

Live calculator

Build vs buy

Lower cost optionBuy is cheaper

$18,155.00 modeled difference over 12 months.

Build total$35,055.00

$21,375.00 upfront plus $1,140.00 monthly maintenance.

Buy total$16,900.00

$2,500.00 setup plus $1,200.00 per month.

Build payback314.6 months

Months until lower build maintenance offsets higher build setup cost.

Planning comparison only. Check estimates, omitted costs, timing, and constraints before making an operating decision.

Formula

Build vs buy formula

Build total = build labor x risk buffer + maintenance cost; buy total = setup cost + monthly vendor cost

The comparison is a cost model only. It does not decide strategy, security, data control, switching cost, or product fit.

How to use

Steps

  1. Enter the estimated internal build hours and loaded hourly cost.
  2. Add monthly maintenance hours and a build risk buffer.
  3. Enter vendor setup and monthly cost.
  4. Compare total cost over the same number of months.

Example

Sample calculation

Build total$30,780
Buy total$16,900
Lower cost optionBuy is cheaper

Calculator use

Best for

  • Pricing, runway, cash flow, or work assumptions before an operating decision.
  • Base, conservative, and optimistic cases with visible inputs.

Before relying on it

Check first

  • The comparison is a cost model only. It does not decide strategy, security, data control, switching cost, or product fit.
  • Mixing scenarios, units, or time periods in one comparison.
  • Leaving out material costs, capacity limits, uncertainty, or dependencies.

Details

What to know before using the result

Loaded costMore than salary

Use a loaded hourly rate that reflects salary, benefits, management time, opportunity cost, and overhead.

Risk bufferBuild uncertainty

Internal builds often need a buffer for scope changes, edge cases, maintenance, security, and integration work.

Cost is not fitQualitative review still needed

Vendor lock-in, data control, compliance, uptime, customization, and strategic differentiation can change the decision.

Benchmarks

How to read the result

Buy cheaper: Vendor advantage.

Often makes sense when the workflow is standard and the vendor already solves it well.

Build cheaper: Internal advantage.

Can make sense when the workflow is core, unusual, or creates durable leverage.

Close result: Qualitative tie-breaker.

When costs are close, use security, speed, ownership, switching cost, and strategic fit as the tie-breakers.

Calculator accuracy

Methodology and assumptions

Formula, inputs, limitations and review record
Formula

Build total = build labor x risk buffer + maintenance cost; buy total = setup cost + monthly vendor cost

Inputs used

Build hours, Loaded hourly cost, Maintenance hours, Risk buffer, Vendor setup cost, Vendor monthly cost, Comparison months

Limitations

Business results depend on contracts, accounting treatment, taxes, payment timing, refunds, collections, and operating assumptions.

Review record

Catalog QA baseline on June 6, 2026. This date marks the catalog-wide automated and editorial QA baseline, not a tool-specific expert review.

Cite this page

Toolkit Shelf. Build vs Buy Calculator. https://toolkitshelf.com/tools/build-vs-buy-calculator

FAQ

Common questions

What does build vs buy mean?

Build vs buy compares creating an internal solution with purchasing a vendor product or service.

What should I include in build cost?

Include design, engineering, testing, project management, launch work, maintenance, support, security, and opportunity cost.

What should I include in buy cost?

Include subscription price, setup fees, implementation time, migration work, training, integrations, support, and likely price increases.

Can the cheaper option still be wrong?

Yes. Cost is only one input. Security, data ownership, vendor risk, strategic importance, and delivery speed can matter more.