How this calculator works
This adds entered reserves without predicting dynamic memory behavior, page cache, shared libraries or swap. Negative remaining memory and utilization above 100% are retained to make an overcommitted plan visible.
The formula
Allocated = OS + database + web + other. Remaining = total − allocated. Utilization = allocated / total × 100.A quick example
A 16 GiB server with reserves of 2, 6, 4 and 1 GiB allocates 13 GiB, leaving 3 GiB and using 81.25% of the budget.
How to use this calculator
- Choose the settings that match your scenario, using the units shown beside each field.
- Enter total ram (gib), operating system reserve (gib), database reserve (gib), web and php reserve (gib).
- Calculate, then review the method and assumptions alongside the results.
A few common questions
Does free memory include reclaimable cache?
This is a planning budget, not a reading of operating-system memory counters. Enter reserves that match your operational policy.
Is a negative remaining value an error?
It identifies a plan that exceeds the entered physical RAM; review the allocations before deployment.