Free tool
How much should an SLA for your internal apps cost?
The SLA calculator is a free tool by Przemysław Zalewski, an independent engineer, for pricing an SLA for internal company apps.
A plant or company runs on its own apps: LEAN boards, health and safety, quality, reports, the warehouse. Someone has to answer when they break. Set the apps, the support window and how often things go wrong, and get a fee, response times and clauses you can paste into the contract.
| Priority | Response | Resolution |
|---|---|---|
| P1: the company or a critical app has stopped | … | … |
| P2: an important function does not work, people can still work | … | … |
| P3: an inconvenience or a change request | … | … |
| Availability | Downtime a month (24/7) | Downtime within the window |
|---|
What goes into the fee
A reserve of hours for interventions you expect, plus routine maintenance of each app, plus an hour of testing after updates for every critical app. Outside business hours, being ready to answer costs extra: here +25% for an extended window and +100% around the clock. Those two numbers are my rule of thumb, not market data; change the window to see the difference.
Response is not resolution
Response is when someone confirms and starts working. Resolution is a workaround for P1, a fix for P2 and a planned fix for P3. Put both in the contract; a fast response with no deadline for the fix is the most common SLA trap.
Availability in minutes
The downtime table is plain arithmetic: 99.5% availability allows about 3.6 hours of downtime in a 30-day month counted around the clock, but under an hour counted only within business hours. Agree which one you mean.
Questions
How do I price an SLA for apps I built for a client?
Start from the hours you actually spend: interventions a month times the hours each one takes, plus routine maintenance. Add readiness if they want answers outside business hours. The clauses below give you a starting contract text.
Do unused hours roll over?
Usually not, because the fee pays for being ready, not only for the work. If the reserve is too large month after month, lower it at the next review.
What is out of scope?
New modules and changes that need design work, hardware failures and outages of third-party services. Those are quoted separately.
Can you run the SLA for our apps?
Yes. I take over the apps, write down how they run and answer within the agreed times. The configurator shows the price and the start date.
Want someone who answers when your apps break?
I take over internal apps, document how they run and keep them working within the times above. A monthly contract you can plan for.
