Costs for FaaS services are based on execution time. Many providers calculate the execution time of each function in 100ms increments and always round up. The minimum execution time they will charge you for is 100ms, so any function that runs for less than 100ms will be billed at 100ms. AWS and Azure however, bills on a 1ms granularity. How much they charge per 100ms is based on memory size.

Below is a brief description of each field:

  • Number of executionstotal number of invocations for your function per month;
  • Average execution timeaverage execution duration of your function;
  • Memory allocationamount of memory your function needs for its work;
  • Use free tierwhether to include free tier quota in the monthly calculations.

How it works?

Many providers use a pay-as-you-use model and the cost entirely depends on your usage. The calculation is based on usage ($/invocation) and execution duration ($/hour). To find the compute costs, you first need to calculate monthly execution duration by multiplying number of executions with duration (s). Afterwards, multiply monthly duration with memory allocation (GB). You will get GB-s compute time per month which is used on all calculations.

Depending on the provider, every month you will get a number of invocations and seconds of compute time for free.

Table below shows the price for invocations and computational time.

Vendor 1m requests price GB/s of compute price
AWS Lambda $ $
Azure Functions $ (ceiled) $
Google Cloud Functions $ $
IBM Cloud Functions $ $


This is a simple calculator that combines several official estimators on a single page. It is used for comparing invocation and compute costs per month on different Cloud Service Providers. The results are exactly equal to the values from official calculators. At the moment, to estimate the costs, it is necessary to go to the web page of the provider and create an estimation individually.

The main purpose of this application is to provide a single page with a user friendly table for comparing several providers in one go.