SaaS vs Custom Build Calculator: The Real 5-Year Cost Comparison
This free SaaS versus custom build calculator compares 5-year subscription cost against the total cost of building and owning custom software, including hosting and ongoing maintenance, so finance and IT leaders can make a build-versus-buy decision on real numbers instead of instinct. Enter your seat count, SaaS price per seat, custom build cost, hosting cost, and maintenance percentage, and the tool returns total cost for each path and the difference. SaaS pricing usually looks cheaper in year one and often is, but seat-based pricing scales with headcount in a way a custom build's cost does not, which is why the crossover point matters more than the sticker price.
Your numbers
Current licensed users; consider running this again at your projected seat count in year 3 and year 5.
Enterprise SaaS seats commonly run $50-$300/user/month depending on the category.
One-time engineering cost to build the custom alternative; see our custom software build cost estimator for a detailed number.
Ongoing maintenance as a percentage of build cost; 15-20% is a common industry planning assumption.
Your results
Planning estimates only. Excludes switching cost from an existing SaaS vendor and assumes stable seat count unless you rerun the calculator at a projected future headcount.
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Why seat-based SaaS pricing changes the math over time
SaaS pricing multiplies by seat count every month for the life of the subscription, so a tool that looks affordable at 50 seats can become one of your largest software line items at 500, especially after typical annual price increases of 5-10% that most SaaS contracts include once the initial term expires. A custom build's cost structure is the opposite: the large expense is upfront, and cost per additional user after launch is close to zero, since hosting and maintenance cost do not scale linearly with seat count the way per-seat licensing does. This is why headcount growth trajectory matters as much as current seat count when running this comparison.
- Run this calculator at your projected seat count in year 3 and year 5, not just today's headcount.
- Factor in typical SaaS renewal price increases of 5-10% annually, which compound the same way seat growth does.
- A custom build's marginal cost per additional user is close to zero once the platform is live.
What custom build cost hides that SaaS pricing does not
SaaS pricing is a known, contracted number; custom build cost is an estimate that can move, and the maintenance percentage in this calculator (commonly 15-20% of build cost annually) covers ongoing support, security patching, and feature updates that a SaaS vendor bundles invisibly into your subscription fee. Underestimating this maintenance line item is the most common way a custom build's real total cost comes in higher than this calculator's headline number. Also budget for the internal product ownership function, someone has to prioritize the roadmap and manage the team building it, a role SaaS vendors absorb into their own product management.
- Maintenance below 15% of build cost annually is rare for actively used enterprise software; validate your assumption.
- Internal product ownership time is a real cost even if it does not appear on an invoice.
- Security patching and compliance updates are the vendor's job with SaaS and your job with a custom build.
When SaaS wins even at high seat counts
SaaS remains the better choice when your requirements closely match what the vendor already built, when you need to be live in weeks rather than months, or when the underlying capability is not differentiated enough to justify owning it outright. It also wins when your organization genuinely lacks the internal capacity to maintain custom software responsibly, since unmaintained custom software degrades faster and more visibly than an underused SaaS seat. Do not build custom software as a cost-saving move alone; build it when the workflow it needs to support is different enough from the market's standard product that a SaaS tool would force your team to change its process to fit the software.
How Netray helps you make this decision with real numbers
Netray builds the custom side of this comparison for manufacturers and defense contractors whose workflows do not fit standard SaaS products, particularly where data residency or ITAR constraints rule out cloud SaaS entirely regardless of the cost comparison. Where SaaS is genuinely the better fit, we say so; several of our engagements start as a build request and end as a vendor selection and integration project instead, once the real numbers are on the table. When custom is the right call, we scope the build, hosting, and maintenance costs that feed this calculator into a real fixed-price plan rather than a rough estimate.
Frequently Asked Questions
At what seat count does custom build usually beat SaaS?
It varies by SaaS price point, but as a rough pattern, custom build tends to become cost-competitive somewhere between 200 and 1,000 seats for mid-priced SaaS products ($50-150/seat/month), assuming a build cost in the low hundreds of thousands and stable annual maintenance. Below that range, SaaS is almost always cheaper because the custom build's fixed cost has not been amortized across enough seats yet. Run your actual numbers through this calculator rather than relying on a rule of thumb.
Does this calculator account for switching cost if we leave a SaaS vendor later?
No, deliberately, since switching cost depends heavily on data portability and integration depth, which vary widely by vendor. If a SaaS product locks your data into a proprietary format or your workflows become deeply dependent on vendor-specific features, factor an additional exit cost into the SaaS total; our software vendor lock-in risk assessment helps quantify that separately.
Is custom build maintenance really 15-20% of build cost every year?
That range is a reasonable industry planning assumption for actively used enterprise software with regular feature updates and security patching, but it varies with codebase quality and how actively the software changes. A stable, rarely-changed application can run closer to 10%; a fast-evolving one with frequent new requirements can exceed 25%. Use our software maintenance cost calculator for a more detailed breakdown specific to your application.
What if we only need the custom build for 2 years, not 5?
Adjust the years input down; the calculator will recompute both totals for your actual horizon. Custom build economics generally look worse over shorter horizons because the large upfront cost has less time to amortize against avoided SaaS fees, so a 2-year horizon favors SaaS more often than a 5-year one does, all else equal.
Should we build a hybrid: custom on top of a SaaS platform?
Often yes, and it is increasingly common: license a SaaS platform for the commodity parts of the workflow and build a thin custom layer for the specific differentiated piece your business actually needs. This calculator compares pure build versus pure buy; for a hybrid, run the SaaS side at your reduced seat count or feature tier and estimate the custom layer separately with our custom software build cost estimator.
Get a real build-versus-buy analysis using your actual seat growth and requirements, not a rough estimate.
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