Build vs. Buy Calculator
Results are estimates based on the values you enter. Recheck your inputs and assumptions before using the output for decisions.
Compare internal build cost with external purchase cost and estimate the break-even quantity.
Build vs. Buy Calculator
Free online build vs. buy calculator to compare the total cost of producing something internally against the total cost of purchasing it from an outside supplier. This calculator is useful for business owners, operations teams, procurement teams, startup founders, project managers, and finance analysts who need a quick way to evaluate make-or-buy decisions. It helps answer an important planning question: is it cheaper to build in-house or buy from a vendor for the required volume?
The calculator works with an internal setup cost, an internal cost per unit, a supplier price per unit, and the required quantity. Internal setup cost represents the upfront investment needed to start producing internally, such as tooling, equipment, onboarding, or system setup. Internal cost per unit covers the direct build cost for each unit. Supplier price per unit is the external purchase cost. Once those values are entered, the calculator shows total build cost, total buy cost, net savings, and the break-even quantity.
The formula of build vs. buy
Total build cost = Internal setup cost + (Internal cost per unit x Quantity)
Total buy cost = Supplier price per unit x Quantity
Net savings = Total buy cost – Total build cost
Break-even quantity = Internal setup cost / (Supplier price per unit – Internal cost per unit)
Here internal setup cost means the fixed upfront cost to build internally, internal cost per unit means the variable internal production cost for one unit, supplier price per unit means the external purchase price for one unit, and quantity means the number of units required. If internal unit cost is lower than supplier cost, the break-even quantity shows the level where internal production starts becoming more economical.
Solved Example
Example 1: Find the build cost, buy cost, savings, and break-even quantity if internal setup cost is $30,000, internal cost per unit is $18, supplier price per unit is $28, and quantity is 5,000 units.
Solve: Total build cost = 30000 + (18 x 5000) = 30000 + 90000 = $120,000
Total buy cost = 28 x 5000 = $140,000
Net savings = 140000 – 120000 = $20,000
Break-even quantity = 30000 / (28 – 18) = 30000 / 10 = 3,000 units
Example 2: Find the result if internal setup cost is $12,000, internal cost per unit is $9, supplier price per unit is $13, and quantity is 2,000 units.
Solve: Total build cost = 12000 + (9 x 2000) = 12000 + 18000 = $30,000
Total buy cost = 13 x 2000 = $26,000
Net savings = 26000 – 30000 = -$4,000
Break-even quantity = 12000 / (13 – 9) = 12000 / 4 = 3,000 units
Example 3: Find the result if internal setup cost is $50,000, internal cost per unit is $22, supplier price per unit is $35, and quantity is 8,000 units.
Solve: Total build cost = 50000 + (22 x 8000) = 50000 + 176000 = $226,000
Total buy cost = 35 x 8000 = $280,000
Net savings = 280000 – 226000 = $54,000
Break-even quantity = 50000 / (35 – 22) = 50000 / 13 = 3,846.15 units
Table of build vs. buy calculator
| Setup Cost | Internal Cost / Unit | Supplier Price / Unit | Quantity | Total Build Cost | Total Buy Cost |
|---|---|---|---|---|---|
| $12,000 | $9 | $13 | 2,000 | $30,000 | $26,000 |
| $30,000 | $18 | $28 | 5,000 | $120,000 | $140,000 |
| $50,000 | $22 | $35 | 8,000 | $226,000 | $280,000 |
| $75,000 | $30 | $42 | 10,000 | $375,000 | $420,000 |
How to use this build vs. buy calculator
Enter the internal setup cost in the proper input field. After that, enter the internal cost per unit and the supplier price per unit. Then enter the required quantity. Finally, click the calculate button. The calculator will show total build cost, total buy cost, net savings, and break-even quantity in the result box. Make sure all values are based on the same product scope and the same quantity assumption.
This calculator is useful when comparing outsourcing, in-house production, software development, component manufacturing, and similar operational choices. If net savings is positive, buying externally costs more than building internally for the selected quantity. If net savings is negative, buying is still cheaper at that level. The break-even quantity helps show when the upfront internal setup cost begins to pay off through lower per-unit economics.
When using the result, remember that build vs. buy decisions often include more than direct cost. Quality control, speed, vendor risk, maintenance, staffing, intellectual property, flexibility, and future demand also matter. This calculator is designed as a fast financial comparison tool, so it works best as a first-pass decision aid. It gives a clear numerical view that supports budgeting, procurement analysis, and production planning.