The comparison between SaaS subscriptions and custom software development is almost always framed around the wrong time horizon. People compare the upfront cost of custom development — which is real, upfront, and visible — against the monthly cost of a SaaS subscription — which is small, recurring, and easy to minimise mentally. Then they choose the SaaS option because the initial outlay is much lower.
Five years later, having paid the subscription every month and added subscriptions to adjacent tools as needs grew, the same person is often paying more annually than they would have spent on a well-built custom system that does not have a monthly fee.
I am going to do the comparison honestly over a five-year period, with real numbers, because the numbers change the calculation significantly and the subscription model makes the long-term cost invisible until it is very large.
The Comparison Scenario
I am going to use a specific scenario: a mid-market service business with 20 employees that needs software to manage: projects and task assignments, client management, invoicing and billing, and basic reporting on project profitability and staff utilisation. This is a realistic scope for a consulting firm, agency, engineering company, or similar.
Two paths:
- Path A: SaaS stack — best-available off-the-shelf tools for each function
- Path B: Custom software — a single integrated system built for this specific workflow
Path A: The SaaS Stack — Year 1 to Year 5
| Tool | Function | Monthly cost (20 users) | Annual cost |
|---|---|---|---|
| Asana Business | Project management | $480 | $5,760 |
| HubSpot Starter CRM | Client management | $500 | $6,000 |
| FreshBooks Premium | Invoicing + billing | $55 | $660 |
| Tableau Creator (3 analysts) | Reporting + analytics | $210 | $2,520 |
| Zapier Professional | Integration between above tools | $100 | $1,200 |
| Year 1 SaaS total | $1,345/mo | $16,140 |
SaaS pricing increases annually. Most platforms raise prices 10-20% per year, particularly as they add features they can charge for. Assuming 12% average annual price increase across the stack:
| Year | Annual SaaS cost | Cumulative |
|---|---|---|
| Year 1 | $16,140 | $16,140 |
| Year 2 | $18,077 | $34,217 |
| Year 3 | $20,246 | $54,463 |
| Year 4 | $22,676 | $77,139 |
| Year 5 | $25,397 | $102,536 |
Additionally:
- Staff time spent on manual data transfer between systems (Zapier automates some but not all cross-system data flow): estimate 3 hours per week per staff member for the 5 people who regularly use multiple systems. 5 people × 3 hours × $30/hour × 50 weeks = $22,500/year, or $112,500 over five years.
- Integration failures and the time to investigate and fix them: estimate 2 hours per month at $50/hour for someone technical. $100/month × 60 months = $6,000.
- New employee ramp-up across four different tools: estimate 3 extra days per new hire × $200/day salary equivalent × 10 new hires over 5 years = $6,000.
Total SaaS path, 5 years: $102,536 (subscription) + $112,500 (data transfer time) + $6,000 (integration maintenance) + $6,000 (onboarding overhead) = $227,036
Path B: Custom Software — Year 1 to Year 5
| Cost item | One-time or annual | Amount |
|---|---|---|
| Custom development (integrated system) | One-time | $55,000 |
| Server hosting (self-hosted or VPS) | Annual | $1,200/year |
| Annual maintenance (updates, bug fixes) | Annual | $5,000/year |
| Feature enhancements (new requirements) | Occasional (est.) | $3,000/year avg. |
| Year | Annual custom cost | Cumulative |
|---|---|---|
| Year 1 | $55,000 (build) + $9,200 | $64,200 |
| Year 2 | $9,200 | $73,400 |
| Year 3 | $9,200 | $82,600 |
| Year 4 | $9,200 | $91,800 |
| Year 5 | $9,200 | $101,000 |
Additional savings compared to SaaS path:
- Staff data transfer time (integrated system — minimal manual transfer): ~0.5 hours per week for 5 people. Saving $3,375/year vs SaaS path, or $16,875 over 5 years.
- Integration maintenance: $0 (integrated system, no third-party integrations to maintain)
- Onboarding: one system to learn instead of four. Estimate saving 2 days per new hire. 10 hires × $200 × 2 = $4,000 saved.
Effective custom path cost accounting for savings: $101,000 – $16,875 – $4,000 = $80,125
The Crossover Point
In this scenario, the two paths cross in terms of cumulative cost at approximately Year 2 to Year 3. By Year 5, the SaaS path costs $227,036 and the custom path costs $80,125 — a difference of nearly $147,000.
Year 1 is painful for the custom path: $64,200 upfront vs $16,140 for the SaaS subscription. But from Year 2 onwards, the custom system’s annual running cost ($9,200) is well below the SaaS stack’s growing subscription cost.
The factor that most significantly accelerates the breakeven: SaaS price increases. If the stack stays flat in price (which is rare), the comparison is closer. If the stack increases at 15-20% annually (which is common, particularly once a vendor reaches market dominance in its category), the custom path looks substantially better even earlier.
What the Comparison Does Not Capture
The five-year financial comparison is important, but it leaves out two factors that are harder to quantify:
Process fit
Custom software is built around how your business actually works. A SaaS stack requires your business to adapt to how the software works. The cost of that adaptation — the workarounds, the processes changed to fit the tool, the features you do not use and the ones you need but do not have — is real but hard to put a precise number on. In some industries and business models, this adaptation cost is acceptable. In businesses where the process is the product (a professional services firm, a specialised manufacturer, a clinic), the adaptation cost is higher.
Vendor risk
SaaS providers change pricing, get acquired, shut down products, and deprecate features. Each of these events triggers a review-and-possibly-replace cycle for your stack. The five-year projection above assumes stable pricing and stable product availability. In practice, at least one of the five tools in a typical SaaS stack will go through a significant change in any five-year period. The custom path has vendor risk in the form of developer availability, but not pricing escalation and not feature deprecation.
Who Should Run This Calculation
The five-year comparison makes sense for businesses that:
- Are running a SaaS stack with annual costs above $10,000-$15,000
- Have a stable core process that has not changed significantly in the last year and is unlikely to change significantly in the next two to three years
- Have 10 or more employees using the systems regularly
- Are experiencing one or more of the signs of outgrowing current software
For businesses below these thresholds, SaaS is almost always the right answer — the custom development upfront cost does not close in the comparison period. For businesses above these thresholds, the comparison is worth running with your actual numbers rather than the illustrative ones I have used here.
Quick Summary
- SaaS vs custom comparisons almost always use the wrong time horizon — comparing upfront custom cost vs first-year SaaS cost rather than 5-year total cost of ownership.
- A typical SaaS stack for a 20-person business costs $16,000-$25,000 per year in subscriptions alone, plus staff time for manual data transfer and integration management.
- A comparable custom system built for $55,000 has annual running costs of $9,000-$10,000 — crossing the SaaS cumulative cost in Years 2-3, and significantly cheaper by Year 5.
- The comparison does not capture SaaS price escalation (common at 10-20% annually), process adaptation cost, or vendor risk — all of which favour custom in a stable, larger business.
- The calculation makes sense for businesses with SaaS costs above $10K-$15K/year, 10+ regular users, and a stable core process.
Running the actual numbers for your business — with your real SaaS costs and a real quote for a custom build — is the only way to know which path is right. The illustrative comparison here is designed to show that the question is worth asking and the answer is not as obvious as Year 1 costs suggest. If you want a real quote to put into your own calculation, start here.