AWS Lambda Cost Calculator

This calculator estimates your monthly AWS Lambda bill from three inputs: monthly invocations, average duration in milliseconds, and allocated memory. It computes compute charges as GB-seconds (memory in gigabytes times duration in seconds times invocations) priced at the per-GB-second rate, then adds a request charge of $0.20 per million invocations. It subtracts the free tier first, so the total is the sum of billable compute and request costs, shown per month and per year.

AWS Lambda includes a perpetual free tier that does not expire: 1,000,000 free requests and 400,000 GB-seconds of compute every month. This calculator subtracts both before pricing the rest, so a small function can come out to $0.00. The free tier is account-wide and shared across all your functions in a region, so turn it off here if other functions already use it up.

A GB-second is one gigabyte of allocated memory held for one second of execution. To find it, convert memory to gigabytes (megabytes divided by 1,024) and multiply by the duration in seconds. For example, 512 MB running for 1 second uses 0.5 GB-seconds, so one million such runs use 500,000 GB-seconds. Lambda bills the total GB-seconds across all invocations after the free tier.

Architecture changes only the compute (duration) rate. x86 costs $0.0000166667 per GB-second, while Arm and Graviton2 cost $0.0000133334 per GB-second, roughly 20 percent less. The request charge of $0.20 per million invocations is the same for both. Many functions run fine on Arm, so switching can cut your duration cost with little or no code change.

Not always. More memory raises the GB-second cost per invocation, but Lambda scales CPU and network with memory, so a function can finish faster at a higher setting. If doubling the memory more than halves the duration, your bill can actually fall. It is worth testing a few memory settings and comparing both cost and speed.

Treat this as a planning estimate, not a billing guarantee or financial advice. It uses first-tier us-east-1 list pricing and excludes data transfer, provisioned concurrency, ephemeral storage above the included 512 MB, regional price differences, higher-volume duration tiers, and taxes. Lambda also bills each invocation rounded up to the nearest millisecond, while this tool uses your average. Confirm current numbers in the AWS Pricing Calculator and your own bill.