Cloud Functions pricing in GCP - Step-by-Step Execution

Process Flow - Cloud Functions pricing

Function Triggered

↓

Count Invocations

↓

Measure Execution Time

↓

Calculate Memory Used

↓

Apply Free Tier Credits

↓

Calculate Cost

↓

Bill User

When a cloud function runs, GCP counts how many times it runs, how long it runs, and how much memory it uses. Then it subtracts free usage and calculates the cost.

Execution Sample

GCP

Trigger function
Count invocation = 1
Execution time = 200ms
Memory used = 256MB
Calculate cost
Apply free tier
Bill user

This traces a single function execution and how pricing is calculated step-by-step.

Process Table

Step	Action	Value	Calculation	Result
1	Function triggered	Invocation count +1	Invocation count = 1	Invocation count = 1
2	Measure execution time	200 ms	Execution time = 200 ms	Execution time = 200 ms
3	Measure memory used	256 MB	Memory used = 256 MB	Memory used = 256 MB
4	Calculate GB-seconds	0.2 sec * 0.256 GB	0.0512 GB-seconds	0.0512 GB-seconds
5	Apply free tier	Free 2 million invocations, 400,000 GB-seconds	No cost for this invocation	Cost = $0
6	Calculate cost	Invocation cost + compute cost	0 invocations charged, 0 compute charged	Total cost = $0
7	Bill user	Total cost	Charge $0 for this invocation	User billed $0

💡 Free tier covers this invocation, so no cost is charged.

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	After Step 5	Final
Invocation count	0	1	1	1	1	1	1
Execution time (sec)	0	0	0.2	0.2	0.2	0.2	0.2
Memory used (GB)	0	0	0	0.256	0.256	0.256	0.256
GB-seconds	0	0	0	0	0.0512	0.0512	0.0512
Cost ($)	0	0	0	0	0	0	0

Key Moments - 2 Insights

Why is the cost zero even though the function ran?

Because the free tier covers 2 million invocations and 400,000 GB-seconds, this single invocation is free as shown in step 5 of the execution table.

How is GB-seconds calculated?

GB-seconds is execution time in seconds multiplied by memory used in GB, as shown in step 4 where 0.2 seconds * 0.256 GB = 0.0512 GB-seconds.

Visual Quiz - 3 Questions

Look at the execution table, what is the invocation count after step 1?

A 2

B 0

C 1

D 256

💡 Hint

Check the 'Invocation count' variable in the execution_table row for step 1.

At which step is the free tier applied to reduce cost?

A Step 3

B Step 5

C Step 2

D Step 7

💡 Hint

Look for the step mentioning 'Apply free tier' in the execution_table.

If the execution time doubled, how would the GB-seconds value change at step 4?

A It would double

B It would halve

C It would stay the same

D It would be zero

💡 Hint

GB-seconds = execution time * memory used, so doubling time doubles GB-seconds (see variable_tracker).

Concept Snapshot

Cloud Functions pricing counts how many times your function runs (invocations), how long it runs (execution time), and how much memory it uses.
Pricing is based on GB-seconds (memory * time) and number of invocations.
Google Cloud offers a free tier: 2 million invocations and 400,000 GB-seconds free each month.
Costs apply only after free tier is exceeded.
Billing happens after calculating usage minus free tier credits.

Full Transcript

When you run a Cloud Function, Google Cloud counts how many times it runs, how long it runs, and how much memory it uses. It multiplies execution time by memory to get GB-seconds. Then it subtracts the free tier amounts. If your usage is within free limits, you pay nothing. Otherwise, you pay for extra invocations and GB-seconds. This example shows a function running once for 200 milliseconds using 256 MB memory. The free tier covers this usage, so the cost is zero. The key steps are counting invocations, measuring time and memory, calculating GB-seconds, applying free tier, and billing the user.