Free tools for engineers

20 calculators, generators and checkers for CI, cloud cost, reliability and team workflows. They run in your browser with published, dated prices; nothing you enter leaves the page.

GitHub Actions

• GitHub Actions cost calculatorEstimate your monthly GitHub Actions bill from minutes per runner type, with included free minutes and per-minute prices for Linux, Windows and macOS.
• GitHub-hosted runner specs lookupLook up any GitHub-hosted runner label (ubuntu-latest, windows-latest, macos-latest and larger runners) and see vCPU, RAM, disk and per-minute price.
• GitHub Actions cron builder and explainerBuild and explain a GitHub Actions schedule cron expression. See it in plain English and the next 10 runs in UTC and your local time.
• GitHub Actions workflow YAML checkerPaste a GitHub Actions workflow and catch missing runs-on, unpinned actions, pull_request_target risks, missing permissions and bad needs.
• GitHub Actions matrix expanderSee every job a GitHub Actions strategy.matrix creates, with include and exclude applied, and the total job count against the 256-job limit.
• Test sharding plannerPaste test durations and split them into balanced shards. See each shard's tests, the expected wall time and the speedup before you change your CI.
• CI minutes forecasterForecast monthly CI minutes and GitHub Actions cost from pull requests per day, pushes per PR, jobs per run and minutes per job. Plan and runner aware.
• GitHub Actions cache key builderBuild a correct actions/cache key with hashFiles patterns and restore-keys for npm, pnpm, pip, Gradle, Maven, Go, Cargo and more. Copy-ready YAML.
• Dependabot config generatorGenerate a dependabot.yml for npm, pip, Docker, GitHub Actions, Go, Cargo and more, with schedule, grouping, labels and reviewers. Validated, copy-ready.

AWS cost

• AWS EC2 cost calculatorCompare monthly and yearly AWS EC2 cost for common instance types on demand, on spot and with a 1-year commitment. Real us-east-1 prices, dated.
• AWS EBS gp3 cost calculatorCalculate monthly AWS EBS gp3 volume cost from size, provisioned IOPS and throughput. Includes the free 3,000 IOPS and 125 MiB/s, with limit checks.
• AWS data transfer cost estimatorEstimate AWS data transfer costs for internet egress, inter-region, cross-AZ traffic and NAT gateways, with the free tier and tiered pricing applied.
• AWS S3 storage cost calculatorEstimate monthly Amazon S3 storage and request costs, and compare Standard, Infrequent Access, Glacier and Deep Archive. Dated us-east-1 prices.

Reliability

• DORA metrics calculatorCalculate the four DORA metrics from your deploy data and see if you rank Elite, High, Medium or Low on each, using the State of DevOps bands.
• Uptime and SLA calculatorConvert uptime percentage (99.9%, 99.99%, five nines) into allowed downtime per day, week, month and year, and see how dependencies in series lower it.
• Error budget calculatorTurn an SLO into an error budget in minutes and requests, track how much you have burned, and get burn-rate alert thresholds for your window.

Team

• Cost of slow CI calculatorWork out what slow CI costs your team each year from engineers, waits per day, minutes per wait and hourly cost, plus the saving from faster builds.
• CODEOWNERS generator and validatorWrite and validate a GitHub CODEOWNERS file. Catch invalid owners and unsupported patterns, and test which owners a file path resolves to.
• Conventional commit and semver bump helperPaste commit messages to check Conventional Commits format, find the next semantic version (major, minor, patch) and generate a changelog.
• On-call rotation generatorGenerate an on-call rotation schedule from a list of people, a time zone and a shift length. See the calendar table and download an ICS file.

Guides

Longer reads on CI speed, cost and reliability. All guides

• CODEOWNERS and Branch Protection Best Practices
• Dependabot Setup That Doesn't Drown Your Team
• Docker Layer Caching in CI With Buildx
• DORA Metrics: What to Measure and How
• How to Find, Fix and Contain Flaky Tests in CI
• Estimating and Forecasting CI Costs for a Growing Team
• Caching in GitHub Actions: Keys, Limits, Examples
• Cron Schedules in GitHub Actions: UTC, Delays, Pitfalls
• GitHub Actions Matrix Builds Done Right
• GitHub Actions OIDC to AWS: No Long-Lived Keys
• GitHub Merge Queue: Setup, Workflows and Pitfalls
• macOS Runners for iOS CI: Costs and Speed-Ups
• Monorepo CI With Nx or Turborepo: Affected Builds
• How to Reduce Your GitHub Actions Bill
• Securing GitHub Actions: A Hardening Checklist
• Self-Hosted vs GitHub-Hosted Runners: Cost and Risk
• How to Speed Up GitHub Actions Workflows
• Speed Up Xcode Builds in CI
• Using Spot Instances for CI Runners on AWS
• Test Sharding and Parallel Tests in GitHub Actions