What a Docker build costs on GitHub Actions
A Docker image build is billed like any other job: its minutes, rounded up, times the rate of the runner it ran on. One build is a few cents. The bill comes from building on every push, so this page prices builds by the hundred on the three standard Linux runners and then over a month on GitHub Team, with this site's calculator.
The three standard Linux runners
GitHub lists three standard Linux runners: 1-core x64 at $0.002 a minute, 2-core x64 at $0.006 and 2-core arm64 at $0.005. A single 10-minute build costs $0.02, $0.06 and $0.05 on them. Per hundred builds:
| Build length | Minutes for 100 builds | Linux 1-core x64 | Linux 2-core x64 | Linux 2-core arm64 |
|---|---|---|---|---|
| 3 minutes | 300 | $0.60 | $1.80 | $1.50 |
| 5 minutes | 500 | $1.00 | $3.00 | $2.50 |
| 10 minutes | 1,000 | $2.00 | $6.00 | $5.00 |
| 20 minutes | 2,000 | $4.00 | $12.00 | $10.00 |
The table holds the build length fixed across runners, which a real build does not do. The 1-core runner charges a third of the 2-core rate, so it is the cheaper choice as long as the build takes less than three times as long there. Whether an image build runs on the 1-core runner at all, and how long it takes, is something to measure on your own workflow; this page only prices the minutes.
Builds are rounded up one by one. A build of 3 minutes and 20 seconds is billed as 4 minutes, every time it runs.
What the layer cache is worth
Most of a Docker build is repeating layers that have not changed. If a layer cache takes a 10-minute build down to 4 minutes, a hundred builds on Linux 2-core x64 cost $2.40 instead of $6.00, a saving of $3.60 per hundred builds.
The cache is not free without limit. Every plan includes 10 GB of Actions cache per repository, and cache beyond that is billed at $0.07 per GB per month. Image layers are large, so check the cache size of a repository before assuming the saving in minutes is the whole story.
A month of image builds on GitHub Team
Take 10-minute builds in a private repository, 22 working days a month, with nothing else drawing on the 3,000 included minutes.
| Builds per day | Minutes per month | Minutes billed | Linux 2-core x64 | Linux 2-core arm64 |
|---|---|---|---|---|
| 10 builds a day | 2,200 | 0 | $0.00 | $0.00 |
| 20 builds a day | 4,400 | 1,400 | $8.40 | $7.00 |
| 40 builds a day | 8,800 | 5,800 | $34.80 | $29.00 |
| 80 builds a day | 17,600 | 14,600 | $87.60 | $73.00 |
Ten builds a day fit inside the allowance. At 40 builds a day the bill is $34.80 a month on x64, $417.60 a year, and $29.00 a month on arm64, $348.00 a year: $5.80 a month less for the same minutes. In a public repository, standard runners are free and the same builds cost $0.00.
The arm64 column assumes you want an arm64 image, or do not care which architecture builds it. An image is built natively for the architecture of its runner.
Images for two architectures
To publish an image for both x64 and arm64, one approach is two native jobs, one on each runner, followed by a short job that joins the results. Two 10-minute builds cost $0.06 plus $0.05, $0.11 per release, before the joining job. The alternative, emulating the second architecture on a single runner, is billed at one rate but usually takes far longer than a native build; time it before choosing, because the bill follows the minutes.
Where larger runners come in
A slow image build is the usual reason to look at a larger runner with more cores. Larger runners have their own per-minute rates, are billed for every minute because they cannot use included minutes, and are not free in public repositories. The rule for comparing is the same as for the 1-core runner above, turned around: a runner with a higher rate lowers the bill only if the build time falls by a bigger factor than the rate rises. The larger-runner rates are in the full version of the calculator, not on this page.
All figures are compute only; seats, registry storage and taxes are left out.
Price your own image builds. Enter your builds per day and your average build length in the free calculator, and set the runner mix to the Linux runner you use.