Build vs buy software calculator
Compare SaaS seats with a custom build year by year, find the break-even point, and check the reasons that are not about cost.
Free, runs in your browser, no sign-up. Updated 2026-10-25.
Result
Over 5 years: buy $168,400, build $270,000. Buy is cheaper. Questions: 0 of 6 yes (leans buy).
- Buy, 5 years
- $168,400
- Build, 5 years
- $270,000
- Difference
- $101,600
- Break-even year
- None
| Year | Buy | Build | Buy total | Build total |
|---|---|---|---|---|
| 1 | $29,000 | $150,000 | $29,000 | $150,000 |
| 2 | $27,700 | $30,000 | $56,700 | $180,000 |
| 3 | $32,000 | $30,000 | $88,700 | $210,000 |
| 4 | $37,000 | $30,000 | $125,700 | $240,000 |
| 5 | $42,700 | $30,000 | $168,400 | $270,000 |
Beyond cost: six questions
Each yes leans towards building. With nobody to own it after launch, buying is usually the better call.
- 1. Is this workflow part of what makes you different from competitors?
- 2. Do you need full control of where the data lives (residency, retention, audit)?
- 3. Does it need deep integration with your own systems that SaaS tools do not offer?
- 4. Have you tried the leading SaaS options and found they force you to change a core process?
- 5. Will per-seat or per-usage pricing grow faster than your revenue?
- 6. Can you fund someone to own and maintain it after launch?
Leans buy (0 of 6 yes)
Assumptions
Every number the result depends on, and where it comes from. Change any value and the result updates.
| Assumption | Value | Source |
|---|---|---|
| Yearly maintenance as a share of build cost | % | OceanLab assumption. No primary source. Covers bug fixes, dependency and security updates, small changes. Raise it for fast-changing products.Reviewed 2026-10-25 |
| Yearly SaaS price increase | % | OceanLab assumption. Placeholder. Check the vendor's renewal terms.Reviewed 2026-10-25 |
Send this comparison to OceanLab
Opens an email to OceanLab with this result and a link to your inputs. Nothing is sent until you press send, and there is no sign-up.
How this is calculated
Buy, per year: seats × price per seat × 12, with seats growing and the price rising each year, plus any one-off setup or migration cost in year one.
Build, per year: the build cost in year one, plus yearly maintenance as a share of the build cost, plus hosting.
The break-even year is the first year the build's running total drops below the buy total.
The six questions below the numbers lean the decision towards build or buy for reasons a spreadsheet misses, such as whether the workflow sets you apart.
Questions about this tool
Why is maintenance included?
Software keeps costing money after launch: fixes, dependency and security updates and small changes. The yearly share is an editable assumption.
When is buying the better choice?
When the workflow is not what makes you different and an off-the-shelf tool fits it. The questions also lean to buy when nobody can own the software after launch.
Does it include migration costs?
Add one-off setup, migration or integration costs for the SaaS option in the buy inputs.
Is anything I enter sent anywhere?
No. The tool runs in your browser and there is no sign-up. Nothing leaves the page unless you choose to email your result to OceanLab.
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