How to use the Software Maintenance Cost Calculator
This calculator estimates what it costs each year to keep custom software running after launch. It multiplies your build cost by an annual maintenance rate, projects that over 3, 5 or 7 years and splits the yearly figure into bug fixes, feature updates, support and hosting. It is for founders, product owners and finance teams setting a budget.
Step by step
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Enter the build cost
Type what the software cost, or will cost, to design and develop into Initial build cost. The default is $150,000 and the arrows move it in steps of $5,000.
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Pick a maintenance rate
Under Annual maintenance rate, choose 15% for a clean, simple system, 18% for a typical one (the default) or 22% for a complex or regulated system.
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Choose the time horizon
Under Time horizon, pick 3 yrs, 5 yrs or 7 yrs. The default is 5 years. The results update as soon as you change anything.
Reading the result
- The headline is the yearly maintenance cost. With the defaults, $150,000 at 18% is $27,000 a year, and the formula line under it shows that multiplication.
- The cards give the total over your horizon, $135,000 over 5 years at the defaults, the average per month, $2,250, and the rate you chose.
- The bars split the yearly figure into fixed shares: Bug fixes (30%), Feature updates (25%), Support & monitoring (25%) and Hosting & infra (20%). At the defaults that is $8,100, $6,750, $6,750 and $5,400.
- The verdict reads Within the common industry range for 15% and 18%, and Above the typical range for 22%.
Tips and common mistakes
- If you do not know the build cost yet, estimate it first and come back. The rate only means something against a real build figure.
- Choose 22% for legacy code, heavy technical debt, strict compliance or a system that must stay up around the clock.
- The split between bug fixes, features, support and hosting is a fixed planning ratio. Check the hosting and support lines against your real bills or quotes.
- Amounts are rounded to whole dollars and shown with a $ sign. For another currency, enter the build cost in that currency and read the $ as your own symbol.
Privacy and limits
The estimate is calculated in your browser. Nothing you enter is sent anywhere or saved, so the defaults come back when you reload the page.
How it works
Software maintenance is everything that keeps a live product healthy after launch: fixing bugs, shipping small feature updates, patching dependencies and security holes, paying for hosting, and monitoring uptime. The most widely used rule of thumb is to budget an annual amount equal to a fixed percentage of what the software originally cost to build.
Most teams land between 15% and 20% of the build cost per year for a reasonably clean, well-documented system. Simpler apps sit at the low end, while legacy codebases, high technical debt, or regulated and high-availability systems push the figure toward 22% or higher. This calculator multiplies your build cost by the rate you choose, projects it across your chosen horizon, and splits the annual figure into four practical buckets so you can see where the money actually goes.
annual maintenance = build cost × annual rate · total = annual × years · split: bug fixes 30%, features 25%, support 25%, hosting 20%
If you don't yet know your build cost, estimate it first with our software development cost calculator, or weigh a custom build against off-the-shelf tools using the build-vs-buy calculator.
FAQs
What is a normal annual software maintenance cost?
The commonly cited industry range is 15-20% of the original build cost per year. A $150,000 build typically carries roughly $22,500-$30,000 in annual maintenance. Simple apps trend lower; complex, legacy, or regulated systems trend higher.
What does the maintenance budget actually cover?
Four main areas: fixing bugs and errors, shipping small feature updates and improvements, hosting and cloud infrastructure, and ongoing support and monitoring (including security patches and dependency upgrades). This tool splits your annual figure across those buckets.
Why is my rate above 20%?
Rates above 20% usually reflect legacy code, accumulated technical debt, strict compliance requirements, or high-availability demands. It's a valid budget, but a code-health review often reduces it back toward the 15-20% range over time.
