diff --git a/README.md b/README.md
index 4ee7399..1ed98cd 100644
--- a/README.md
+++ b/README.md
@@ -722,7 +722,8 @@ tags: |
   type=sha,format=long
 ```
 
-Output Git short commit (or long if specified) as Docker tag like `sha-ad132f5`.
+Output Git short commit (or long if specified) as Docker tag like
+`sha-860c1904a1ce`.
 
 Extended attributes and default values:
 
diff --git a/__tests__/meta.test.ts b/__tests__/meta.test.ts
index 5a03f79..fb00174 100644
--- a/__tests__/meta.test.ts
+++ b/__tests__/meta.test.ts
@@ -310,14 +310,14 @@ describe('push', () => {
       } as Inputs,
       {
         main: 'dev',
-        partial: ['sha-860c190'],
+        partial: ['sha-860c1904a1ce'],
         latest: false
       } as Version,
       [
         'org/app:dev',
-        'org/app:sha-860c190',
+        'org/app:sha-860c1904a1ce',
         'ghcr.io/user/app:dev',
-        'ghcr.io/user/app:sha-860c190'
+        'ghcr.io/user/app:sha-860c1904a1ce'
       ],
       [
         "org.opencontainers.image.created=2020-01-10T00:30:00.000Z",
@@ -343,14 +343,14 @@ describe('push', () => {
       } as Inputs,
       {
         main: 'edge',
-        partial: ['sha-2665741'],
+        partial: ['sha-266574110acf'],
         latest: false
       } as Version,
       [
         'org/app:edge',
-        'org/app:sha-2665741',
+        'org/app:sha-266574110acf',
         'ghcr.io/user/app:edge',
-        'ghcr.io/user/app:sha-2665741'
+        'ghcr.io/user/app:sha-266574110acf'
       ],
       [
         "org.opencontainers.image.created=2020-01-10T00:30:00.000Z",
@@ -376,14 +376,14 @@ describe('push', () => {
       } as Inputs,
       {
         main: 'edge',
-        partial: ['sha-860c190'],
+        partial: ['sha-860c1904a1ce'],
         latest: false
       } as Version,
       [
         'org/app:edge',
-        'org/app:sha-860c190',
+        'org/app:sha-860c1904a1ce',
         'ghcr.io/user/app:edge',
-        'ghcr.io/user/app:sha-860c190'
+        'ghcr.io/user/app:sha-860c1904a1ce'
       ],
       [
         "org.opencontainers.image.created=2020-01-10T00:30:00.000Z",
@@ -408,13 +408,13 @@ describe('push', () => {
         ],
       } as Inputs,
       {
-        main: 'sha-2665741',
+        main: 'sha-266574110acf',
         partial: [],
         latest: false
       } as Version,
       [
-        'org/app:sha-2665741',
-        'ghcr.io/user/app:sha-2665741'
+        'org/app:sha-266574110acf',
+        'ghcr.io/user/app:sha-266574110acf'
       ],
       [
         "org.opencontainers.image.created=2020-01-10T00:30:00.000Z",
@@ -424,7 +424,7 @@ describe('push', () => {
         "org.opencontainers.image.source=https://github.com/octocat/Hello-World",
         "org.opencontainers.image.title=Hello-World",
         "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
-        "org.opencontainers.image.version=sha-2665741"
+        "org.opencontainers.image.version=sha-266574110acf"
       ],
       undefined
     ],
@@ -439,13 +439,13 @@ describe('push', () => {
         ],
       } as Inputs,
       {
-        main: 'sha-983315b',
+        main: 'sha-983315b5e8d4',
         partial: [],
         latest: false
       } as Version,
       [
-        'org/app:sha-983315b',
-        'ghcr.io/user/app:sha-983315b'
+        'org/app:sha-983315b5e8d4',
+        'ghcr.io/user/app:sha-983315b5e8d4'
       ],
       [
         "org.opencontainers.image.created=2020-01-10T00:30:00.000Z",
@@ -455,7 +455,7 @@ describe('push', () => {
         "org.opencontainers.image.source=https://github.com/octocat/Hello-World",
         "org.opencontainers.image.title=Hello-World",
         "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
-        "org.opencontainers.image.version=sha-983315b"
+        "org.opencontainers.image.version=sha-983315b5e8d4"
       ],
       undefined
     ],
@@ -1341,17 +1341,17 @@ describe('tag', () => {
       } as Inputs,
       {
         main: '1.0.0',
-        partial: ['1.0', 'sha-860c190'],
+        partial: ['1.0', 'sha-860c1904a1ce'],
         latest: true
       } as Version,
       [
         'org/app:1.0.0',
         'org/app:1.0',
-        'org/app:sha-860c190',
+        'org/app:sha-860c1904a1ce',
         'org/app:latest',
         'ghcr.io/user/app:1.0.0',
         'ghcr.io/user/app:1.0',
-        'ghcr.io/user/app:sha-860c190',
+        'ghcr.io/user/app:sha-860c1904a1ce',
         'ghcr.io/user/app:latest'
       ],
       [
@@ -1381,17 +1381,17 @@ describe('tag', () => {
       } as Inputs,
       {
         main: '1.0.0',
-        partial: ['1.0', 'sha-860c190'],
+        partial: ['1.0', 'sha-860c1904a1ce'],
         latest: true
       } as Version,
       [
         'org/app:1.0.0',
         'org/app:1.0',
-        'org/app:sha-860c190',
+        'org/app:sha-860c1904a1ce',
         'org/app:latest',
         'ghcr.io/user/app:1.0.0',
         'ghcr.io/user/app:1.0',
-        'ghcr.io/user/app:sha-860c190',
+        'ghcr.io/user/app:sha-860c1904a1ce',
         'ghcr.io/user/app:latest'
       ],
       [
@@ -1423,17 +1423,17 @@ describe('tag', () => {
       } as Inputs,
       {
         main: '1.0.0-dev',
-        partial: ['1.0', 'sha-860c190-dev'],
+        partial: ['1.0', 'sha-860c1904a1ce-dev'],
         latest: true
       } as Version,
       [
         'org/app:1.0.0-dev',
         'org/app:1.0',
-        'org/app:sha-860c190-dev',
+        'org/app:sha-860c1904a1ce-dev',
         'org/app:latest',
         'ghcr.io/user/app:1.0.0-dev',
         'ghcr.io/user/app:1.0',
-        'ghcr.io/user/app:sha-860c190-dev',
+        'ghcr.io/user/app:sha-860c1904a1ce-dev',
         'ghcr.io/user/app:latest'
       ],
       [
@@ -1460,16 +1460,16 @@ describe('tag', () => {
         ]
       } as Inputs,
       {
-        main: 'v1.1.1-860c190-foo',
+        main: 'v1.1.1-860c1904a1ce-foo',
         partial: [
           'master-foo'
         ],
         latest: false
       } as Version,
       [
-        'org/app:v1.1.1-860c190-foo',
+        'org/app:v1.1.1-860c1904a1ce-foo',
         'org/app:master-foo',
-        'ghcr.io/user/app:v1.1.1-860c190-foo',
+        'ghcr.io/user/app:v1.1.1-860c1904a1ce-foo',
         'ghcr.io/user/app:master-foo'
       ],
       [
@@ -1480,7 +1480,7 @@ describe('tag', () => {
         "org.opencontainers.image.source=https://github.com/octocat/Hello-World",
         "org.opencontainers.image.title=Hello-World",
         "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
-        "org.opencontainers.image.version=v1.1.1-860c190-foo"
+        "org.opencontainers.image.version=v1.1.1-860c1904a1ce-foo"
       ],
       undefined
     ],
@@ -2334,14 +2334,14 @@ describe('pr', () => {
       } as Inputs,
       {
         main: 'pr-15',
-        partial: ['sha-a9c8c58'],
+        partial: ['sha-a9c8c5828b91'],
         latest: false
       } as Version,
       [
         'org/app:pr-15',
-        'org/app:sha-a9c8c58',
+        'org/app:sha-a9c8c5828b91',
         'ghcr.io/user/app:pr-15',
-        'ghcr.io/user/app:sha-a9c8c58'
+        'ghcr.io/user/app:sha-a9c8c5828b91'
       ],
       [
         "org.opencontainers.image.created=2020-01-10T00:30:00.000Z",
@@ -2366,14 +2366,14 @@ describe('pr', () => {
         ]
       } as Inputs,
       {
-        main: 'sha-a9c8c58',
+        main: 'sha-a9c8c5828b91',
         partial: ['pr-15'],
         latest: false
       } as Version,
       [
-        'org/app:sha-a9c8c58',
+        'org/app:sha-a9c8c5828b91',
         'org/app:pr-15',
-        'ghcr.io/user/app:sha-a9c8c58',
+        'ghcr.io/user/app:sha-a9c8c5828b91',
         'ghcr.io/user/app:pr-15'
       ],
       [
@@ -2384,7 +2384,7 @@ describe('pr', () => {
         "org.opencontainers.image.source=https://github.com/octocat/Hello-World",
         "org.opencontainers.image.title=Hello-World",
         "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
-        "org.opencontainers.image.version=sha-a9c8c58"
+        "org.opencontainers.image.version=sha-a9c8c5828b91"
       ],
       undefined
     ],
@@ -2467,14 +2467,14 @@ describe('pr', () => {
         ]
       } as Inputs,
       {
-        main: 'sha-2665741',
+        main: 'sha-266574110acf',
         partial: ['pr-15'],
         latest: false
       } as Version,
       [
-        'org/app:sha-2665741',
+        'org/app:sha-266574110acf',
         'org/app:pr-15',
-        'ghcr.io/user/app:sha-2665741',
+        'ghcr.io/user/app:sha-266574110acf',
         'ghcr.io/user/app:pr-15'
       ],
       [
@@ -2485,7 +2485,7 @@ describe('pr', () => {
         "org.opencontainers.image.source=https://github.com/octocat/Hello-World",
         "org.opencontainers.image.title=Hello-World",
         "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
-        "org.opencontainers.image.version=sha-2665741"
+        "org.opencontainers.image.version=sha-266574110acf"
       ],
       undefined
     ],
@@ -2539,14 +2539,14 @@ describe('pr', () => {
       {
         main: 'pr-15',
         partial: [
-          'sha-2665741',
+          'sha-266574110acf',
           'sha-266574110acf203503badf966df2ea24b5d732d7'
         ],
         latest: false
       } as Version,
       [
         'org/app:pr-15',
-        'org/app:sha-2665741',
+        'org/app:sha-266574110acf',
         'org/app:sha-266574110acf203503badf966df2ea24b5d732d7'
       ],
       [
@@ -2691,14 +2691,14 @@ describe('pr-head-sha', () => {
       } as Inputs,
       {
         main: 'pr-15',
-        partial: ['sha-3370e22'],
+        partial: ['sha-3370e228f220'],
         latest: false
       } as Version,
       [
         'org/app:pr-15',
-        'org/app:sha-3370e22',
+        'org/app:sha-3370e228f220',
         'ghcr.io/user/app:pr-15',
-        'ghcr.io/user/app:sha-3370e22'
+        'ghcr.io/user/app:sha-3370e228f220'
       ],
       [
         "org.opencontainers.image.created=2020-01-10T00:30:00.000Z",
@@ -2722,14 +2722,14 @@ describe('pr-head-sha', () => {
         ]
       } as Inputs,
       {
-        main: 'sha-3370e22',
+        main: 'sha-3370e228f220',
         partial: ['pr-15'],
         latest: false
       } as Version,
       [
-        'org/app:sha-3370e22',
+        'org/app:sha-3370e228f220',
         'org/app:pr-15',
-        'ghcr.io/user/app:sha-3370e22',
+        'ghcr.io/user/app:sha-3370e228f220',
         'ghcr.io/user/app:pr-15'
       ],
       [
@@ -2740,7 +2740,7 @@ describe('pr-head-sha', () => {
         "org.opencontainers.image.source=https://github.com/octocat/Hello-World",
         "org.opencontainers.image.title=Hello-World",
         "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
-        "org.opencontainers.image.version=sha-3370e22"
+        "org.opencontainers.image.version=sha-3370e228f220"
       ]
     ],
     [
@@ -2820,14 +2820,14 @@ describe('pr-head-sha', () => {
         ]
       } as Inputs,
       {
-        main: 'sha-3370e22',
+        main: 'sha-3370e228f220',
         partial: ['pr-15'],
         latest: false
       } as Version,
       [
-        'org/app:sha-3370e22',
+        'org/app:sha-3370e228f220',
         'org/app:pr-15',
-        'ghcr.io/user/app:sha-3370e22',
+        'ghcr.io/user/app:sha-3370e228f220',
         'ghcr.io/user/app:pr-15'
       ],
       [
@@ -2838,7 +2838,7 @@ describe('pr-head-sha', () => {
         "org.opencontainers.image.source=https://github.com/octocat/Hello-World",
         "org.opencontainers.image.title=Hello-World",
         "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
-        "org.opencontainers.image.version=sha-3370e22"
+        "org.opencontainers.image.version=sha-3370e228f220"
       ]
     ],
     [
@@ -2890,14 +2890,14 @@ describe('pr-head-sha', () => {
       {
         main: 'pr-15',
         partial: [
-          'sha-3370e22',
+          'sha-3370e228f220',
           'sha-3370e228f2209994d57af4427fe64e71bb79ac96'
         ],
         latest: false
       } as Version,
       [
         'org/app:pr-15',
-        'org/app:sha-3370e22',
+        'org/app:sha-3370e228f220',
         'org/app:sha-3370e228f2209994d57af4427fe64e71bb79ac96'
       ],
       [
@@ -3121,14 +3121,14 @@ describe('schedule', () => {
       } as Inputs,
       {
         main: 'nightly',
-        partial: ['sha-860c190'],
+        partial: ['sha-860c1904a1ce'],
         latest: false
       } as Version,
       [
         'org/app:nightly',
-        'org/app:sha-860c190',
+        'org/app:sha-860c1904a1ce',
         'ghcr.io/user/app:nightly',
-        'ghcr.io/user/app:sha-860c190'
+        'ghcr.io/user/app:sha-860c1904a1ce'
       ],
       [
         "org.opencontainers.image.created=2020-01-10T00:30:00.000Z",
@@ -3154,7 +3154,7 @@ describe('schedule', () => {
         ]
       } as Inputs,
       {
-        main: 'sha-860c190',
+        main: 'sha-860c1904a1ce',
         partial: [
           'nightly',
           'defbranch'
@@ -3162,10 +3162,10 @@ describe('schedule', () => {
         latest: false
       } as Version,
       [
-        'org/app:sha-860c190',
+        'org/app:sha-860c1904a1ce',
         'org/app:nightly',
         'org/app:defbranch',
-        'ghcr.io/user/app:sha-860c190',
+        'ghcr.io/user/app:sha-860c1904a1ce',
         'ghcr.io/user/app:nightly',
         'ghcr.io/user/app:defbranch'
       ],
@@ -3177,7 +3177,7 @@ describe('schedule', () => {
         "org.opencontainers.image.source=https://github.com/octocat/Hello-World",
         "org.opencontainers.image.title=Hello-World",
         "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
-        "org.opencontainers.image.version=sha-860c190"
+        "org.opencontainers.image.version=sha-860c1904a1ce"
       ],
       undefined
     ],
diff --git a/src/meta.ts b/src/meta.ts
index f7d47a6..d80fa31 100644
--- a/src/meta.ts
+++ b/src/meta.ts
@@ -307,7 +307,7 @@ export class Meta {
 
     let val = this.context.sha;
     if (tag.attrs['format'] === tcl.ShaFormat.Short) {
-      val = this.context.sha.substring(0, 7);
+      val = this.context.sha.substring(0, 12);
     }
 
     const vraw = this.setValue(val, tag);
@@ -373,7 +373,7 @@ export class Meta {
         return context.ref.replace(/^refs\/tags\//g, '');
       },
       sha: function () {
-        return context.sha.substring(0, 7);
+        return context.sha.substring(0, 12);
       },
       base_ref: function () {
         if (/^refs\/tags\//.test(context.ref) && context.payload?.base_ref != undefined) {