What does it cost to build a custom business system?
A custom business system usually costs SEK 1–10 million to build, depending on how many processes and integrations it needs to cover. The calculation is best weighed against five years of license costs for an equivalent standard system. The most underestimated line items are data migration and parallel running – together they can account for a significant share of the budget.
A custom business system is one of the bigger decisions a company can make on the IT side. Used correctly, it replaces or complements a standard system whose licenses grow with every user – and shapes itself around the business instead of the other way around. But the investment is substantial, and the calculation needs to be done honestly. Here’s the pricing and how to calculate it.
When a custom business system is worth considering
Three situations come up repeatedly. The standard system doesn’t cover the core process, and the customizations have piled up so much that every upgrade is a project of its own. The license cost scales with the number of users and has grown into one of the larger recurring IT line items. Or: the process is itself the competitive edge, and a system every competitor can buy levels that edge out.
Conversely, pure standard needs – bookkeeping, payroll, basic inventory – should almost never be built from scratch. Standard systems are both cheaper and better there.
Price range: SEK 1–10 million
| Scope | Typical cost |
|---|---|
| Base system replacing a core process | SEK 1,000,000–3,000,000 |
| Several modules with integrations | SEK 3,000,000–6,000,000 |
| Full business system for the whole company | SEK 6,000,000–10,000,000+ |
What moves the price within the range is the number of processes, the number of integrations with other systems, the data volumes to be migrated, and the requirements on permissions, traceability, and reporting.
The five-year calculation: license vs. build
The right comparison isn’t build cost against a monthly invoice, but total cost over a reasonable horizon – five years is a good rule of thumb.
A worked example. Say you have 120 users on a licensed system that costs SEK 900 per user per month: that’s just under SEK 1.3 million a year, about SEK 6.5 million over five years – plus implementation and the customizations already made. Weigh that against a custom system for SEK 3 million with maintenance at 15–25% a year: roughly SEK 5.3–6 million total over the same period, and after that a significantly lower annual cost since no licenses scale with the users.
The same calculation with 30 users ends the opposite way: the license wins clearly. The point isn’t that building always pays off, but that the calculation decides – number of users, license tier, and how long the system needs to live.
The most underestimated line items: migration and parallel running
Two budget items are almost always missing from the first calculation.
Data migration. Years of customer data, order history, and product data need to move – and above all, get cleaned up. Duplicates, fields used for the wrong things, and information that only exists in the heads of experienced staff make this its own sub-project. It’s not unusual for migration to account for 10–20% of the budget.
Parallel running. During the transition, the old and new systems run at the same time: double operating costs, remaining licenses, and staff who for a period enter data into two systems. Plan the transition process by process and set a date when the old system actually shuts down – otherwise parallel running becomes permanent.
How to reduce the risk
Build in phases where each phase goes into live use before the next is decided. Start with the process where the standard system chafes the most, and keep standard where standard is enough. And run a real discovery phase first – on a project of this size, a few weeks of requirements work is the cheapest insurance there is.
Thinking about replacing or complementing your business system? At Weapp we build custom systems and are happy to help with the calculation – get in touch and we’ll run the numbers on your case.
Frequently asked questions
Isn't a standard system always cheaper?
With few users and standard needs, yes – licenses are almost always the right choice then. The calculation flips when the license cost scales with many users, when the standard system's customizations pile up on top of each other, or when the system forces the business into ways of working that cost more than they're worth.
How long does it take to build a custom business system?
A first module replacing a core process often takes six to twelve months. A system covering several parts of the business is best built in phases over one to three years, with each phase going live and paying off before the next starts.
What does data migration cost in a business system project?
It's not unusual for migration and cutover to account for 10–20% of the project budget. The biggest part is rarely the move itself but the cleanup: duplicates, fields used incorrectly for years, and data that only exists in the heads of experienced staff.
Can we build custom on top of our current business system?
Yes, that's a common middle ground. Keep the standard system for finance, inventory, and other areas where standard is enough, and build custom modules for the processes that make you unique. The integration between the parts then becomes the key technical question to solve early.
What happens to the system if the vendor disappears?
Make sure you own the source code, that it sits in a version control account you control, and that the architecture is documented. If the system is built on widely used technologies, another team can take over without starting from scratch. Write this into the contract before the project begins.