Physical memory or RAM usage in Percentage

roopesh_shetty 

There is similar solution for Disk Space in Use and Capacity.  Which looks like this for Memory:

Perf
//| where Computer startswith "DC02" 
// add other computers here
| where ObjectName == "Memory" 
| where CounterName == "Available MBytes"
| summarize GBFree=avg(CounterValue) by Computer,bin(TimeGenerated, 5m)
| summarize arg_max(TimeGenerated, *) by Computer
|join kind= inner
(
    Perf
    | where ObjectName == "Memory" 
    | where CounterName == "% Committed Bytes In Use"
    | summarize PctFree=avg(CounterValue) by Computer,bin(TimeGenerated, 5m)
    | summarize arg_max(TimeGenerated, *) by Computer
)
on Computer 
| project   TotalSizeGB=round(GBFree*100/PctFree,0), 
            round(PctFree,2),
            round(GBFree,2), 
            Computer
| summarize FreePCT=avg(PctFree) by Computer,
            TotalSizeGB,
            FreeGB = round(GBFree / 1024,2)

Go to Log Analytics and Run Query

However you will need some other data points.  As the results look like this (just filtered on a single VM for ease)

Go to Log Analytics and Run Query

The final two columns are right, but the "TotalSizeGB" isn't right  - you need to also subtract from that number the Cached Memory and the Paged Pool and the Non_paged Pool  

You can see those 3 fields from Task Manager:

That's as far as I have time for now; I suspect we need a different counter or 3 more counters.

Maybe you are ok with the result, its not Physical RAM (as you asked for) but Total Available RAM inc cached etc...
FreePCT (Free %) is correct