Software Total Cost of Ownership Calculator

The build quote is only the down payment. Real total cost of ownership is the build plus every year you host, maintain and support the software. Set your numbers below to see the honest multi-year TCO of a custom build, and where the money actually goes.

§ · written guide

How to use the Software Total Cost of Ownership Calculator

This calculator adds up what custom software really costs over several years, not just the build quote. It takes the one-time build cost and adds hosting, yearly maintenance as a percentage of the build, and support, each multiplied across the time horizon you pick. It is for founders, product owners and finance teams budgeting a custom build.

Step by step

Enter the build cost
Type the upfront price to design and build the software into One-time build cost. The default is $150,000. Use a real quote if you have one.
Add monthly hosting
Enter what you expect to pay each month for servers, databases and third party services into Hosting & infrastructure / month. The default is $800.
Set the maintenance rate
Drag the Maintenance / year slider between 12% and 25% of the build cost. The default is 18%. This covers bug fixes, dependency and security updates and small changes.
Add support if you have it
Enter any monthly cost for a help desk, monitoring or on call cover into Support & ops / month. It starts at $0; leave it there if you have none.
Pick the time horizon
Under Time horizon choose 3 yrs, 5 yrs or 7 yrs. The default is 5 years. Every recurring cost is multiplied by the number of years you pick; the build is counted once.

Reading the result

The large figure under Total cost of ownership is the full total. With the defaults it is $333,000 over 5 years.
The line below splits it into its parts in thousands: Build $150k + hosting $48k + maintenance $135k + support $0. Hosting is $800 × 12 × 5, and maintenance is 18% of $150,000 for each of 5 years.
The colored box looks at how much of the total is running cost rather than build. Under 35% reads Build-heavy, upkeep stays modest; 35% to just under 55% reads Upkeep is a real, ongoing line item; 55% or more reads Running costs dominate this TCO. The defaults land at about 55%, just under the top band.
The cards show each bucket, plus Avg per year, which is the total divided by the years ($67k with the defaults). The Build (one-time) card is highlighted when the build costs at least as much as all the running costs combined.

Tips and common mistakes

Do not set maintenance to the bottom of the range just to make the total look smaller. Underfunding maintenance is the usual trap, and the real upkeep bill arrives whatever number you typed.
Switch between 3 yrs and 7 yrs to see how quickly running costs catch up with the build. Over longer horizons they often pass it.
Hosting and support are entered per month, while maintenance is a yearly percentage. Do not enter a yearly hosting bill in the monthly box.
Compare two vendors by running each quote through the calculator with the same horizon, so a cheap build with high upkeep does not look better than it is.

Privacy and limits

The math runs in your browser. Nothing you type is sent anywhere or saved, and a reload brings back the default values. The result is a planning estimate from the simple formula above, not a quote.

Back to the tool

How it works

The total cost of ownership (TCO) of custom software is the sum of what you pay once and what you keep paying every year it runs. The build is a single upfront cost; hosting, maintenance and support are recurring, so they scale with your time horizon. Look only at the build quote and you'll routinely under-budget by a wide margin.

Maintenance is the line most teams get wrong. A working system still needs bug fixes, dependency and security updates, and small changes as your business shifts, which is why the accepted planning figure is 15-20% of the original build cost per year. Hosting covers cloud, databases and third-party services; support covers monitoring, on-call and any help desk or SLA you commit to.

This calculator adds those four buckets over your chosen 3, 5 or 7-year window so you can see the real number and, just as important, where it goes, often the running costs quietly overtake the build itself.

TCO = build cost + (hosting/mo × 12 × years) + (build cost × maintenance % × years) + (support/mo × 12 × years)

To pin down the build figure first, run your scope through the software development cost calculator, or weigh custom against off-the-shelf with the build vs buy calculator. For a system several departments will run on for years, our enterprise software page sets out what the build includes. To compare builders, see the nine custom software development companies we scored.

FAQs

What is the total cost of ownership of custom software?

It's the one-time build cost plus every recurring cost of running the software over its life, hosting and infrastructure, ongoing maintenance, and support or operations. Over several years those recurring costs often match or exceed the original build, so TCO is a far more honest number than the build quote alone.

How much should I budget for software maintenance each year?

A widely used planning figure is 15-20% of the original build cost per year, covering bug fixes, dependency and security updates, and small enhancements. Complex or fast-moving products land at the higher end; simple, stable ones can sit lower. Underfunding maintenance is the most common TCO mistake.

Why is TCO higher than the build quote?

The build quote is a one-time cost, but software has to be hosted, maintained and supported for years afterward. Multiply modest monthly hosting and a mid-teens maintenance percentage across a 5-year horizon and the running total frequently rivals the build, which is exactly why comparing TCO, not sticker price, matters.