Semver Calculator

What Is Semantic Versioning

Semantic Versioning (SemVer) is a versioning convention that communicates the nature of changes between software releases through a structured three-part version number: MAJOR.MINOR.PATCH. By following SemVer, package authors tell consumers exactly what to expect from an upgrade — whether it will break existing integrations, add new features, or fix bugs.

SemVer (semver.org) is the standard versioning scheme for npm, Cargo (Rust), Go modules, Composer (PHP), and most modern package ecosystems. Understanding SemVer is essential for managing dependencies, writing version constraints, and making informed upgrade decisions.

SemVer Components

Component	When to Increment	Example	Signal to Users
MAJOR (X.0.0)	Breaking changes to the public API	2.0.0 → 3.0.0	Code changes required to upgrade
MINOR (0.X.0)	New features, backward-compatible	2.3.0 → 2.4.0	New capabilities, existing code works
PATCH (0.0.X)	Bug fixes, backward-compatible	2.4.1 → 2.4.2	Safer to upgrade, existing code works

Pre-release and Build Metadata

Format	Meaning	Example
1.0.0-alpha	Pre-release: unstable, may change	Testing, early access
1.0.0-beta.2	Pre-release with iteration	Beta testing
1.0.0-rc.1	Release candidate	Final testing before stable
1.0.0+build.123	Build metadata (ignored in precedence)	CI/CD tracking

Version Ranges (npm syntax)

Syntax	Meaning	Accepts
^1.2.3	Compatible with 1.x.x	>=1.2.3, <2.0.0
~1.2.3	Approximately 1.2.x	>=1.2.3, <1.3.0
>=1.2.3	Minimum version	1.2.3 and above
1.2.x	Any patch version	>=1.2.0, <1.3.0
*	Any version	Everything

Common Use Cases

• Dependency management: Write correct version constraints in package.json, Cargo.toml, or requirements.txt to get updates without breaking changes
• Release planning: Determine the correct version number for your next release based on the nature of changes since the last release
• Upgrade risk assessment: Evaluate whether upgrading a dependency is safe (patch), potentially beneficial (minor), or risky (major)
• Changelog management: Organize release notes by version, helping users understand what changed and when
• CI/CD automation: Automate version bumping in CI/CD pipelines based on commit message conventions (Conventional Commits)

Best Practices

1. Follow SemVer strictly — Releasing a breaking change as a minor version erodes user trust. If you change or remove public API behavior, increment the major version.
2. Start at 0.1.0 for new projects — Versions below 1.0.0 signal that the API is unstable and may change without major version bumps. Release 1.0.0 when your public API is stable.
3. Use caret (^) ranges for most dependencies — ^1.2.3 allows automatic minor and patch updates while preventing breaking changes. This is npm's default and the recommended approach.
4. Pin exact versions for applications — Libraries should use ranges, but applications should pin exact versions (with lock files) for reproducible builds.
5. Document breaking changes prominently — When releasing a major version, provide a migration guide that lists every breaking change and how to adapt.