CPU Credit Usage Calculator

Work out cpu credit usage instantly with clear inputs, formula shown and shareable results.

About CPU Credit Usage Calculator

Burstable instances earn CPU credits at the baseline rate and spend them whenever utilisation exceeds it, where one credit is one vCPU-minute at 100 percent. Running above baseline is therefore only sustainable in bursts: at 45 percent against a 20 percent baseline, the instance burns credits steadily and will be throttled to baseline once the balance reaches zero.

Formula

Credit balance

earned per hour = baseline x vCPUs x 60; consumed per hour = utilisation x vCPUs x 60; hours to exhaustion = balance / net burn rate

Worked example

With the default values below, CPU Credit Usage Calculator returns Hours until credits run out of 9.6. Change any input above and every figure here is recalculated in your browser.

Inputs used

Baseline CPU performanceaccepts 1–100 %: 20 %
Actual CPU utilisationaccepts 0–100 %: 45 %
vCPUsminimum 1: 2
Current credit balanceminimum 0: 288

Results

Hours until credits run out: 9.6 h
Credits earned per hour: 24.0
Credits consumed per hour: 54.0
Sustainability: Burning credits - the instance will throttle to baseline once they run out

Step by step

1Values used
2Credit balance
3Hours until credits run out= 9.6 h
4Credits earned per hour= 24.0
5Credits consumed per hour= 54.0
6Sustainability= Burning credits - the instance will throttle to baseline once they run out

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What happens when credits run out?

In standard mode the instance is throttled to its baseline, which is often a fraction of nominal performance. In unlimited mode it keeps bursting and you are billed for surplus credits.

When is a burstable instance the wrong choice?

For any workload with sustained utilisation above baseline. Once you are regularly paying surplus credit charges, a fixed-performance instance is cheaper and more predictable.