diff --git a/version/version.go b/version/version.go
new file mode 100644
index 0000000..b495528
--- /dev/null
+++ b/version/version.go
@@ -0,0 +1,40 @@
+// Package version is a companion library to the //version/spec proto.
+package version
+
+import (
+	"fmt"
+	"strings"
+
+	"source.monogon.dev/version/spec"
+)
+
+// Release converts a spec.Version's Release field into a SemVer 2.0.0 compatible
+// string in the X.Y.Z form.
+func Release(v *spec.Version) string {
+	if v == nil || v.Release == nil {
+		return "0.0.0"
+	}
+	rel := v.Release
+	return fmt.Sprintf("%d.%d.%d", rel.Major, rel.Minor, rel.Patch)
+}
+
+// Semver converts a spec.Version proto message into a SemVer 2.0.0 compatible
+// string.
+func Semver(v *spec.Version) string {
+	ver := "v" + Release(v)
+	var prerelease []string
+	if git := v.GitInformation; git != nil {
+		if n := git.CommitsSinceRelease; n != 0 {
+			prerelease = append(prerelease, fmt.Sprintf("dev%d", n))
+		}
+		prerelease = append(prerelease, fmt.Sprintf("g%s", git.CommitHash[:8]))
+		if git.BuildTreeState != spec.Version_GitInformation_BUILD_TREE_STATE_CLEAN {
+			prerelease = append(prerelease, "dirty")
+		}
+	}
+
+	if len(prerelease) > 0 {
+		ver += "-" + strings.Join(prerelease, ".")
+	}
+	return ver
+}