Is building a custom system cheaper than per-seat SaaS fees over five years?
For most teams of ten or more, yes: typically within 12 to 24 months. The key shift is paying once for a build (usually shared across a founding cohort) plus a flat annual running fee, rather than a bill that multiplies with every new hire and rises every year. As Forbes notes: if your tool is "a simple database, a form and a dashboard," you are almost certainly overpaying rent.
Why per-seat SaaS costs compound
Every hire adds to the bill. Every annual review adds to the bill. There is no finish line.
Per-seat SaaS pricing has two compounding factors most finance teams under-model: headcount growth and annual price increases. A tool at €20/seat/month for 20 users costs €4,800/year today. At 10% annual price growth and a team that doubles in three years, the same tool costs over €15,000/year by year five, and you still own nothing at the end.
When custom software beats per-seat SaaS
More than 10 users + more than €100/month total = custom likely wins by year two.
The crossover depends on three inputs: current annual SaaS cost, build cost (shared across co-funders), and headcount growth rate. For field-service, ATS, and scheduling tools at €30–90/seat, break-even for a 20-user team is typically year one or early year two. For cheaper tools at €5–10/seat, it takes a larger team or longer horizon, but the direction is the same.
Side-by-side comparison
| Per-seat SaaS | Your own system | |
|---|---|---|
| Cost model | Per user, per month: compounds with headcount and annual price increases | One-off build cost (shared across a founding cohort) + flat annual running fee |
| Build cost | €0 | ~€8,000 (your share of a ~€40,000 build, split across ~5 co-founders) |
| Annual cost: 20 users at €10/seat/mo | ~€2,400/yr, and rising each year | ~€2,500/yr flat: add unlimited users |
| Year 3: 30 users, 10% annual rise | ~€4,400/yr | €2,500/yr, no change |
| 5-year cumulative | ~€22,000+ (and accelerating) | ~€20,500 (build share + 5 × €2,500 running) |
| If the team doubles | Cost roughly doubles | No change: flat fee, unlimited users |
| When you stop paying | Access gone, your data is held by the vendor | Perpetual, escrow-backed licence: you keep access and your data |
Related questions
For teams of 10 or more using a mid-tier SaaS (€5–15/user/month), payback usually falls between 12 and 24 months after launch. For higher-cost tools like field-service or scheduling SaaS (€30–80/user/month), payback can be under a year. Use the savings calculator on the home page for your specific numbers.
Sources
- Forbes: "Why small businesses are increasingly replacing SaaS with custom software" (2024)
- Retool 2026 State of Internal Tools: ~35% of organisations have already replaced a SaaS with custom software; ~78% plan to replace more
- Zylo 2026 SaaS Management Index: ~46% of SaaS licences unused
- Rollout IT build and running-cost estimates
See what your SaaS spend looks like with a flat annual fee
Enter your seat count and current monthly price. The calculator uses real build-cost estimates and shows you the five-year crossover.