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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.

Formula checked June 6, 2026Assumptions visiblePlanning 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.

Use this for planning and comparison. Contracts, collections, payables, tax timing, payroll, refunds, one-time bills, seasonality, and accounting treatment can change the real business result.

Quick answer

Build vs Buy Calculator: what it calculates

Build vs Buy Calculator calculates lower cost option from build hours, loaded hourly cost, maintenance hours, risk buffer, vendor setup cost and vendor monthly cost, and additional inputs. The visible formula is Build total = build labor x risk buffer + maintenance cost; buy total = setup cost + monthly vendor cost.

ResultLower cost option
InputsBuild hours, Loaded hourly cost, Maintenance hours, Risk buffer, Vendor setup cost, Vendor monthly cost, Comparison months
FormulaBuild vs buy formula

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

  • Use this build vs buy calculator to compare internal build cost with vendor purchase cost before committing team time or budget.
  • Calculating build vs buy formula with the method and assumptions visible.
  • Comparing the output with the sample calculation and benchmark table before using it elsewhere.
  • Pricing, runway, cash flow, or work assumptions before an operating decision.

Before relying on it

Check first

  • Using the lower cost option without checking that build hours, loaded hourly cost and maintenance hours, and additional inputs match the same task and context.
  • Ignoring that the comparison is a cost model only. It does not decide strategy, security, data control, switching cost, or product fit.
  • Relying on the number without checking whether the visible assumptions match the real-world task.
  • Mixing cash and accounting profit, or monthly recurring items and one-time items.

Details

What to know before using the result

These notes make the assumptions explicit, especially where the same search query can mean slightly different things.

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

The calculator is a decision aid, not a fixed rule. Use the output to compare scenarios and document your assumptions. Benchmark ranges are broad planning heuristics unless this page names a specific source for the range.

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

The formula, inputs, example, and limitations are shown so the result is checkable, not just a number in a box.

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.

Last reviewed

June 6, 2026

Cite this page

Toolkit Shelf. Build vs Buy Calculator. Last reviewed June 6, 2026. 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.

Can this replace accounting or legal advice?

No. Business tools are scenario planners. Contracts, taxes, payment timing, accounting treatment, refunds, and legal requirements can change decisions.

What should I do after using a business tool?

Save the assumptions, compare a conservative scenario, and review the result with actual books, contracts, or an advisor before making a high-stakes decision.