System Load Calculator
Combine 1/5/15-minute load averages into a weighted trend indicator.
Inputs
Weighted Combined Load
4.420
Trend
Rising — recent load (1-min) is notably higher than the 5/15-minute averages; system load is climbing.
Combined Load per Core
1.105
Severity
Overloaded — combined load exceeds available core capacity; expect queuing.
Step by step
Values used
1-Minute Load Average = 5.20; 5-Minute Load Average = 4; 15-Minute Load Average = 3.10; CPU Cores = 4
Weighted combined load
combined_load = load_1min × 0.5 + load_5min × 0.3 + load_15min × 0.2
Weighted Combined Load
= 4.420
Trend
= Rising — recent load (1-min) is notably higher than the 5/15-minute averages; system load is climbing.
Combined Load per Core
= 1.105
Severity
= Overloaded — combined load exceeds available core capacity; expect queuing.
How it works
The three load average figures Linux reports (1, 5 and 15-minute exponentially-weighted moving averages of the run-queue length) each smooth over a different window, so comparing them to each other reveals a trend that no single number shows: 1-min running noticeably higher than 5/15-min signals load is currently rising, while the reverse signals a recent spike subsiding. Weighting them (0.5/0.3/0.2, favoring recency) into one combined figure gives a single trend-aware number for dashboards or alerting thresholds, without discarding the longer-window context entirely.
Formula
Weighted combined load
combined_load = load_1min × 0.5 + load_5min × 0.3 + load_15min × 0.2
- L_1
- 1-minute load average
- L_5
- 5-minute load average
- L_{15}
- 15-minute load average
Frequently Asked Questions
Why do 1, 5 and 15-minute load averages sometimes disagree so much?
Because they're independently-decaying exponential moving averages, not simple windowed averages — a short, sharp spike shows up strongly in the 1-minute figure almost immediately, but takes much longer to meaningfully move the 15-minute figure, which is exactly what makes comparing them useful for spotting whether load is currently rising or falling.
What does 'load average' actually count on Linux?
It counts the average number of processes in the run queue (runnable, waiting for CPU) plus processes in uninterruptible sleep (typically waiting on disk I/O) — not just CPU-runnable tasks. This is why load average can be high even when CPUs look idle, if many processes are blocked on slow storage.
Is a load average equal to the number of cores 'fully loaded but fine'?
Roughly, yes — load average equal to core count generally means the CPUs are fully utilized with essentially no queuing. Load average significantly above core count indicates tasks are waiting for a turn on the CPU (or for I/O), and load average well below it indicates spare capacity.