diff --git a/src/lib/format.js b/src/lib/format.js
new file mode 100644
index 00000000..6748d0da
--- /dev/null
+++ b/src/lib/format.js
@@ -0,0 +1,8 @@
+import keyMirror from 'keymirror';
+
+const Formats = keyMirror({
+    BITMAP: null,
+    VECTOR: null
+});
+
+export default Formats;
diff --git a/src/reducers/format.js b/src/reducers/format.js
new file mode 100644
index 00000000..a8a2f7c4
--- /dev/null
+++ b/src/reducers/format.js
@@ -0,0 +1,32 @@
+import Formats from '../lib/format';
+import log from '../log/log';
+
+const CHANGE_FORMAT = 'scratch-paint/formats/CHANGE_FORMAT';
+const initialState = Formats.VECTOR;
+
+const reducer = function (state, action) {
+    if (typeof state === 'undefined') state = initialState;
+    switch (action.type) {
+    case CHANGE_FORMAT:
+        if (action.format in Formats) {
+            return action.format;
+        }
+        log.warn(`Format does not exist: ${action.format}`);
+        /* falls through */
+    default:
+        return state;
+    }
+};
+
+// Action creators ==================================
+const changeFormat = function (format) {
+    return {
+        type: CHANGE_FORMAT,
+        format: format
+    };
+};
+
+export {
+    reducer as default,
+    changeFormat
+};
diff --git a/src/reducers/scratch-paint-reducer.js b/src/reducers/scratch-paint-reducer.js
index 258dea9e..224dcad7 100644
--- a/src/reducers/scratch-paint-reducer.js
+++ b/src/reducers/scratch-paint-reducer.js
@@ -4,6 +4,7 @@ import brushModeReducer from './brush-mode';
 import eraserModeReducer from './eraser-mode';
 import colorReducer from './color';
 import clipboardReducer from './clipboard';
+import formatReducer from './format';
 import hoverReducer from './hover';
 import modalsReducer from './modals';
 import selectedItemReducer from './selected-items';
@@ -17,6 +18,7 @@ export default combineReducers({
     color: colorReducer,
     clipboard: clipboardReducer,
     eraserMode: eraserModeReducer,
+    format: formatReducer,
     hoveredItemId: hoverReducer,
     modals: modalsReducer,
     selectedItems: selectedItemReducer,
diff --git a/test/unit/format-reducer.test.js b/test/unit/format-reducer.test.js
new file mode 100644
index 00000000..5b12ca43
--- /dev/null
+++ b/test/unit/format-reducer.test.js
@@ -0,0 +1,24 @@
+/* eslint-env jest */
+import Formats from '../../src/lib/format';
+import reducer from '../../src/reducers/format';
+import {changeFormat} from '../../src/reducers/format';
+
+test('initialState', () => {
+    let defaultState;
+    expect(reducer(defaultState /* state */, {type: 'anything'} /* action */) in Formats).toBeTruthy();
+});
+
+test('changeFormat', () => {
+    let defaultState;
+    expect(reducer(defaultState /* state */, changeFormat(Formats.BITMAP) /* action */)).toBe(Formats.BITMAP);
+    expect(reducer(Formats.BITMAP /* state */, changeFormat(Formats.BITMAP) /* action */))
+        .toBe(Formats.BITMAP);
+    expect(reducer(Formats.BITMAP /* state */, changeFormat(Formats.VECTOR) /* action */))
+        .toBe(Formats.VECTOR);
+});
+
+test('invalidChangeMode', () => {
+    expect(reducer(Formats.BITMAP /* state */, changeFormat('non-existant mode') /* action */))
+        .toBe(Formats.BITMAP);
+    expect(reducer(Formats.BITMAP /* state */, changeFormat() /* action */)).toBe(Formats.BITMAP);
+});