NOC coverage planning, headcount by headcount.

Coverage comes in steps, and the steps are not evenly spaced.

Headcount buys coverage in steps rather than in a straight line. One person is business hours. Three is around the clock on weekdays. Five is the first number that reaches every hour of the week. After five, more people stop buying hours and start buying company, and at eleven they stop buying coverage altogether.

Every row below comes from the same two numbers. A week is 168 hours and a full time week is 40, so a team of N supplies N times 40 hours and can cover whatever fits inside that. Three people supply 120 hours, which is exactly around the clock from Monday to Friday. Five supply 200, which is the first total above 168.

That is why the steps are uneven. Going from two people to three closes the weekday nights. Going from four to five closes the weekend. Going from six to seven closes nothing at all, because six already reaches every hour, and what the seventh changes is the last column rather than the first.

The left half of the table is what a headcount can reach. The right half is how thin it is while it reaches it, and the two rarely improve together.

The steps are uneven on purpose. Coverage climbs fast up to five people, which is the first headcount that reaches every hour of the week, and then it stops climbing and the last column takes over. Hours with one person on peak at 168 with five people and fall away from there, reaching zero at eleven, where every hour already has two people on and another person adds depth rather than coverage.

A week can be fully covered and still be one person's attention from end to end. Those are different claims about the same rota, and usually only the first one gets made. The last column is the one to read twice, because it is the difference between somebody being on and somebody being able to look away for ten minutes.

It also explains why the answer to better coverage is sometimes not more coverage. Between five people and eleven, every extra person removes solo hours rather than adding covered ones. That is a real improvement and it is a different purchase, so it deserves a different sentence.

The numbers assume a 40 hour week, whole shifts, and everybody turning up. Real teams have training days, handovers that overlap, somebody who does not work nights, and two sites in different timezones. So read a row as the floor. When it says five people reach every hour, it means five people reach every hour of a week where all five are there.

The free planner is for the part the ladder cannot do. Take a generated week into it, put your own names on it, move the windows to the hours your alerts actually arrive in, and export the result to a calendar, a spreadsheet or a printed sheet for the wall.

Signal9 is alert and on call software for operations teams, and the calculator is a free tool from it. The reason it reports hours with one person on as a number of its own is that this is where software earns its place on a small desk. One person watching four consoles misses the fourth one. Signal9 puts the alerts in one view, keeps the record of what the last shift did so the next one does not start from nothing, and for the hours with nobody at the desk the alerts you marked most urgent keep escalating until somebody answers.

How do you do coverage planning for a NOC? Start from hours rather than from people. Decide what the desk has to cover, count it in hours a week, and divide by a full time week. Around the clock is 168 hours, so it needs 4.2 people before leave and training. Weekdays only around the clock is 120 hours, which is three people. Then ask the second question, which is how many of those hours end up with one person on.

How many people do you need for 24x5 coverage? Three. Around the clock from Monday to Friday is 120 hours, which three people cover on eight hour shifts inside a full week each. A fourth person adds weekend daytimes, and a fifth is the first headcount that reaches every hour of the week.

When does hiring another NOC engineer stop adding coverage? At eleven, on a 40 hour week. By then every hour already has two people on, so a twelfth adds depth rather than hours. Below five, the next person adds hours nobody had. Between five and eleven, the next person removes hours where somebody is on their own.