An €80,000 quote for a business application is not a price. It's a down payment. Over five years the same application will cost roughly twice that, sometimes more, and a vendor who doesn't say so upfront is saving an awkward conversation for year two. Custom software total cost of ownership needs no crystal ball, though. A public day-rate grid and some arithmetic get you there.
That's the exercise here. Our rates are public: 150, 200, 300, 400 and 450 EUR per day depending on the profile. Every line of the model below is computed from that grid, and you can check the build line in two clicks on our quote page. A custom software total cost of ownership figure you can't verify isn't a model. It's a sales pitch.
We've shipped more than 17 projects for more than ten clients, including a booking platform for airport parking we still operate. We know where the money goes after go-live. Here's the full table.
Why the first quote covers about 40% of the total
Nothing shady here, and nothing unusual. The build quote prices the visible part: scoping, building, testing, shipping. Everything else starts the day you go live. Servers run, dependencies age, users ask for changes, and one day you'll want to leave or rewrite. The industry itself admits to corrective maintenance of 15 to 25% of build cost per year. That number sits in contracts. It rarely makes the sales deck.
In our model, build lands between 36 and 42% of the five-year total. The first quote is, at best, half the story.
The five blocks of custom software total cost of ownership
Every cost of ownership breaks into five blocks. A vendor who prices only one is leaving you to guess the other four.
- Build: scoping, architecture, development, testing, delivery management. The quote you sign.
- Run: hosting, monitoring, backups, security patching.
- Corrective maintenance: bugs, broken dependencies, incidents. The famous 15 to 25% a year.
- Evolution: the business requests that start in month one of real usage. They always come.
- Exit: documentation, handover, data export the day you switch vendors or rewrite.
The worked model, line by line
Take a typical business application: it carries a core company workflow, some thirty screens, integrations with what already exists. Build, on our public grid:
- Scoping and architecture: 12 days at €450 = €5,400
- Senior development: 130 days at €300 = €39,000
- Mid-level development: 90 days at €200 = €18,000
- Testing and QA: 35 days at €200 = €7,000
- Delivery management: 25 days at €400 = €10,000
Build total: 292 days, €79,400. Then the lifetime:
- Run: 12 days a year at €300 = €3,600 a year, €18,000 over five years, hosting excluded
- Corrective maintenance: 15 to 25% of €79,400, so €12,000 to €20,000 a year from year two
- Evolution: 30 days a year at €300 = €9,000 a year from year two
- Exit: 20 days at €300 = €6,000 reserved for handover
The five-year total sits between €187,000 and €219,000, against an initial quote of €79,400.
Every line in this table is a multiplication. If you can't redo it yourself, someone is hiding something.
What 15 to 25% a year actually buys
Good corrective maintenance is invisible. Dependencies stay current, vulnerabilities get patched before anyone exploits them, bugs die in days rather than weeks. On the airport parking platform we operate, that budget pays for regular version upgrades and an on-call rotation that doesn't improvise.
The number drifts in three cases. A stack that ages without upgrades, so every patch becomes an expedition. A team that churns, so the new engineer rediscovers the system on your dime. And the classic one: evolution disguised as maintenance. When the invoice grows but the bug list doesn't shrink, you're buying development at patch prices, with no scoping and no acceptance. Demand two separate lines in the contract.
How the team model bends the curve
Our setup is hybrid: steering, quality and contracts in Belgium and Switzerland, an engineering center in Rabat. The effect on the table is direct. The €450 profile works where it changes the outcome, architecture and reviews. The volume runs at €200 and €300. And the tail, maintenance and evolution included, is billed at engineering-center rates, not steering rates.
Run the test: take the spreadsheet and swap our senior line for a local agency's rate. If that rate is double, the maintenance and evolution blocks double with it, and the cumulative gap over four years exceeds the original build. You negotiate the build once. You pay the tail every year.
When the evolution volume justifies a standing team instead of tickets, our full pods run between €15,000 and €40,000 a month. Known capacity, known cost, no renegotiation per request.
Against a SaaS subscription, honestly
This comparison deserves better than a reflex. On the SaaS side, write the formula: seats, times monthly price, times 60 months, plus integration, data migration and renewal increases. A hypothetical subscription at €50 per seat for 100 users weighs €300,000 over five years, with no asset on the balance sheet at the end.
Our position is simple. Standard need, accounting, payroll, generic CRM: buy the SaaS today and never pay anyone to rebuild it. A workflow that sets you apart, seat counts that grow, integrations that pile up: the custom curve crosses under the subscription somewhere between year two and year four, and the asset is yours.
Stress-test any vendor's number
Before signing, five questions, in order:
- Is the day-rate grid public? No grid, no verifiable model.
- What does the maintenance percentage cover, line by line?
- What's the evolution assumption, in days per year? Zero isn't an assumption, it's denial.
- Is the exit cost written into the contract: documentation, export, handover?
- Redo the multiplications. If the five-year total looks like the build quote, the number is wrong, probably in good faith.
Where the model stops
The model assumes a stable scope: a product pivot resets the build line, and no percentage anticipates that. Hosting varies too much across architectures to price here. And our 30 evolution days a year are an average: a living application can burn double that in its first year. The table gives an honest order of magnitude, not a promise to the cent.
All of it fits in a spreadsheet and takes an hour to fill. For the first line, price your own scope on jadev-corp.com/quote: a formal quotation, reviewed by an engineer within one business day, with a start possible two weeks after the request. The rest of the table, you can now compute yourself.