AWS Lambda has revolutionized the way developers build and scale applications by offering serverless computing, where you only pay for what you use. But understanding the actual cost of running Lambda functions can be challenging, especially when dealing with different memory allocations, invocation frequencies, and execution durations. That’s where the AWS Lambda Cost Calculator becomes indispensable.
AWS Lambda Cost Calculator
What is the AWS Lambda Cost Calculator?
The AWS Lambda Cost Calculator is an online tool that estimates your monthly costs based on how your Lambda functions are used. It takes into account:
- Memory size (in MB)
- Number of invocations per month
- Average duration per invocation (in milliseconds)
- Request count
- Additional AWS services (e.g., API Gateway, CloudWatch Logs)
By providing these details, you can get a close estimate of your AWS Lambda bill.
How AWS Lambda Pricing Works
Before diving into the calculator, it’s important to understand how AWS charges for Lambda:
1. Invocation Charges
You pay $0.20 per 1 million requests.
2. Duration Charges
You are billed based on the number of GB-seconds used. Duration is measured in milliseconds, rounded up to the nearest millisecond.
Formula:
Duration Cost = (Memory in GB) × (Execution Time in seconds) × (Number of Invocations) × $0.00001667
3. Free Tier
- 1 million free requests per month
- 400,000 GB-seconds of compute time per month
These free tiers apply per month and reset automatically.
How to Use the AWS Lambda Cost Calculator
Here’s how to effectively use the AWS Lambda Cost Calculator:
- Enter Memory Size
Choose how much memory your Lambda function uses (e.g., 128MB, 512MB, 1024MB, etc.). - Input Number of Monthly Invocations
Estimate how many times the function is triggered per month. - Enter Average Execution Time
Input the average run time per invocation in milliseconds. - Include Free Tier (Optional)
Select whether to apply AWS’s Free Tier allowance. - Add Optional Services
You can factor in costs for services like API Gateway or CloudWatch Logs if your Lambda functions use them. - View Estimated Monthly Cost
The calculator will show the expected monthly cost with and without the free tier.
Example Calculation
Let’s say you run a Lambda function with:
- Memory: 512MB
- Invocations: 5 million per month
- Duration: 200 milliseconds
- Free Tier Applied
Step 1: Convert Memory to GB
512MB = 0.5 GB
Step 2: Convert Execution Time
200 ms = 0.2 seconds
Step 3: Calculate GB-seconds
0.5 GB × 0.2 seconds = 0.1 GB-seconds per invocation
0.1 × 5,000,000 = 500,000 GB-seconds
Step 4: Apply Free Tier
- 1M free invocations = 4M billable
- 400K free GB-seconds = 100K billable
Step 5: Calculate Costs
- Requests: (4M ÷ 1M) × $0.20 = $0.80
- Compute Time: 100,000 × $0.00001667 = $1.67
- Total: $0.80 + $1.67 = $2.47/month
Key Benefits of Using the AWS Lambda Cost Calculator
- ✅ Precise Estimations: Avoid surprises on your AWS bill.
- ✅ Free Tier Awareness: Shows impact of AWS’s generous free allowances.
- ✅ Custom Scenarios: Simulate different memory sizes and usage patterns.
- ✅ Budget Planning: Helps with architecture design and cost optimization.
- ✅ Supports Cost Tracking for Other AWS Services: Add-on costs for API Gateway, DynamoDB, etc., can be included.
Additional Insights
Optimize for Cost
- Lower memory = lower cost, but may increase duration if underpowered.
- Consider tuning for performance-cost balance.
Monitor with CloudWatch
- Use CloudWatch to get real metrics for duration and invocation count. This will improve the accuracy of your calculator inputs.
Consider Cold Starts
Cold start latency doesn’t directly impact cost, but it may affect user experience—especially for low-invocation, high-duration functions.
20 Frequently Asked Questions (FAQs)
1. What is the AWS Lambda Cost Calculator used for?
It estimates monthly charges based on function usage—memory, duration, and invocations.
2. Is it accurate for real-world usage?
Yes, if you provide realistic metrics, it’s very close to what AWS will bill.
3. How does AWS bill duration?
Duration is rounded up to the nearest millisecond, then multiplied by memory used (in GB).
4. What is GB-second?
It’s a billing unit: 1 GB-second = 1 GB of memory used for 1 second.
5. Are the first million invocations free every month?
Yes, AWS provides 1 million free requests per month under the Free Tier.
6. Is the Free Tier always applied?
Only if you enable it in the calculator and are eligible (i.e., within first 12 months or using a Free Tier-qualified account).
7. What if my function runs for less than 100ms?
AWS bills by the millisecond, so 1ms minimum duration is applied.
8. What’s the cost for 128MB memory?
It’s the lowest tier—cheaper, but may slow down function performance.
9. Does the calculator support multiple functions?
Yes, just repeat the process for each and sum the totals.
10. Does it factor in API Gateway costs?
Yes, if you add it manually or use a version that includes it.
11. Can I simulate cost after scaling?
Yes, you can test with higher invocation numbers or durations.
12. How do I reduce Lambda costs?
Optimize code, use smaller memory allocations, and limit invocation frequency.
13. What’s the pricing after the Free Tier?
$0.20 per 1M requests and $0.00001667 per GB-second of compute time.
14. Does this include CloudWatch charges?
Not by default. Add $0.30 per month per metric as an estimate.
15. Can I use this tool for Step Functions?
No, this calculator is specifically for Lambda. Use AWS Step Function pricing calculators for that.
16. Does memory size affect performance?
Yes, more memory means faster execution—can reduce total duration cost.
17. Do I need to include network bandwidth usage?
Lambda itself doesn’t charge for bandwidth, but other services might.
18. Can I export the result?
Most calculators allow exporting or saving the estimate as a report.
19. How often should I recalculate?
Whenever your usage pattern changes or you’re about to deploy new code.
20. Is the calculator free to use?
Yes, it’s freely accessible and doesn’t require login.
Final Thoughts
AWS Lambda is powerful, scalable, and cost-efficient—if you manage it well. The AWS Lambda Cost Calculator helps developers and businesses understand what they’ll spend based on actual usage patterns. It’s essential for budgeting, architecture planning, and identifying opportunities for cost optimization.