Runtime bills compute with no one-minute minimum. It bills CPU by the work it measures: $0.025 per active vCPU-hour, which is a CPU-second at a 3,600th of that. Memory is billed while the sandbox runs, at $0.0075 per GiB-hour. A pause stops compute billing immediately (pricing).
A short history
Clouds billed virtual machines by the hour until 2 October 2017. On that day, Amazon announced that EC2 Linux instances "will be billed on one second increments, with a minimum of 60 seconds". Other clouds followed. Functions went further. AWS Lambda bills duration by the millisecond.
What the unit hides
The unit is only half of the bill. The other half is what is counted in each second:
| Billing | A one-minute run, 2 vCPUs, busy for 10 seconds |
|---|---|
| Per hour, allocated vCPUs | A full hour of 2 vCPUs |
| Per second, 60-second minimum | 60 seconds of 2 vCPUs |
| Per second, allocated vCPUs | 60 seconds of 2 vCPUs |
| Per second, measured CPU | 20 CPU-seconds, plus memory for 60 seconds |
Rounding matters for short runs too. A provider that rounds each run up to the minute bills a ten-second check as sixty seconds. CodeSandbox does this. On 40-second runs, the example job costs $2.48 on CodeSandbox and $0.47 on Runtime (CodeSandbox vs AWS Lambda MicroVMs).
Worked on Runtime
1,000 runs of a 2 vCPU, 4 GiB sandbox, 60 seconds each, with 20 CPU-seconds of work per run:
textCPU: 1,000 × 20 s / 3,600 × $0.025 = $0.14Memory: 1,000 × 60 s / 3,600 × 4 GiB × $0.0075 = $0.50Total: $0.64Related
- What is serverless computing?
- What is a CPU floor?
- What is a spending limit?
- Sandbox cost calculator
Sources
Checked 25 October 2026.