diff --git a/HISTORY.md b/HISTORY.md
index e5c58212a1..dfb1eee0f4 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -7,7 +7,9 @@ Breaking changes:
 
 - Improvements in calculation of the `dot` product of complex values. 
   The first argument is now conjugated. See #1761. Thanks @m93a.  
-
+- Change function `size` to always return an `Array` as output instead
+  of returning a `Matrix` when the input is a matrix or 
+  `config.matrix == 'Array'`. See #1771.
 
 # 2020-03-29, version 6.6.2
 
diff --git a/docs/datatypes/matrices.md b/docs/datatypes/matrices.md
index 8c90122e7c..b5383078ba 100644
--- a/docs/datatypes/matrices.md
+++ b/docs/datatypes/matrices.md
@@ -155,8 +155,8 @@ Math.js uses geometric dimensions:
 - A vector is one-dimensional.
 - A matrix is two or multi-dimensional.
 
-The size of a matrix can be calculated with the function `size`. Function `size`
-returns a `Matrix` or `Array`, depending on the configuration option `matrix`.
+The size of a matrix can be calculated with the function `size`. 
+Function `size` always returns an `Array`.
 Furthermore, matrices have a function `size` as well, which always returns
 an Array.
 
diff --git a/docs/expressions/syntax.md b/docs/expressions/syntax.md
index 4cc2121bb4..f3b1c5096c 100644
--- a/docs/expressions/syntax.md
+++ b/docs/expressions/syntax.md
@@ -408,7 +408,7 @@ parser.evaluate('"hello"')                        // String, "hello"
 
 // string manipulation
 parser.evaluate('a = concat("hello", " world")')  // String, "hello world"
-parser.evaluate('size(a)')                        // Matrix [11]
+parser.evaluate('size(a)')                        // Array [11]
 parser.evaluate('a[1:5]')                         // String, "hello"
 parser.evaluate('a[1] = "H"')                     // String, "H"
 parser.evaluate('a[7:12] = "there!"')             // String, "there!"
diff --git a/src/function/matrix/size.js b/src/function/matrix/size.js
index e3d6fd4ff8..009b1ca524 100644
--- a/src/function/matrix/size.js
+++ b/src/function/matrix/size.js
@@ -1,14 +1,15 @@
 import { arraySize } from '../../utils/array'
 import { factory } from '../../utils/factory'
-import { noMatrix } from '../../utils/noop'
 
 const name = 'size'
-const dependencies = ['typed', 'config', '?matrix']
+const dependencies = ['typed']
 
-export const createSize = /* #__PURE__ */ factory(name, dependencies, ({ typed, config, matrix }) => {
+export const createSize = /* #__PURE__ */ factory(name, dependencies, ({ typed }) => {
   /**
    * Calculate the size of a matrix or scalar.
    *
+   * The function always returns an Array, also for Matrix input.
+   *
    * Syntax:
    *
    *     math.size(x)
@@ -27,24 +28,22 @@ export const createSize = /* #__PURE__ */ factory(name, dependencies, ({ typed,
    *     resize, squeeze, subset
    *
    * @param {boolean | number | Complex | Unit | string | Array | Matrix} x  A matrix
-   * @return {Array | Matrix} A vector with size of `x`.
+   * @return {Array} A vector with size of `x`.
    */
   return typed(name, {
     Matrix: function (x) {
-      return x.create(x.size())
+      return x.size()
     },
 
     Array: arraySize,
 
     string: function (x) {
-      return (config.matrix === 'Array') ? [x.length] : matrix([x.length])
+      return [x.length]
     },
 
     'number | Complex | BigNumber | Unit | boolean | null': function (x) {
       // scalar
-      return (config.matrix === 'Array')
-        ? []
-        : matrix ? matrix([]) : noMatrix()
+      return []
     }
   })
 })
diff --git a/test/unit-tests/expression/parse.test.js b/test/unit-tests/expression/parse.test.js
index 4ce0c46d8d..e0f464e85d 100644
--- a/test/unit-tests/expression/parse.test.js
+++ b/test/unit-tests/expression/parse.test.js
@@ -592,7 +592,7 @@ describe('parse', function () {
     it('should get/set the matrix correctly for 3d matrices', function () {
       const scope = {}
       assert.deepStrictEqual(parseAndEval('f=[1,2;3,4]', scope), math.matrix([[1, 2], [3, 4]]))
-      assert.deepStrictEqual(parseAndEval('size(f)', scope), math.matrix([2, 2]))
+      assert.deepStrictEqual(parseAndEval('size(f)', scope), [2, 2])
 
       parseAndEval('f[:,:,2]=[5,6;7,8]', scope)
       assert.deepStrictEqual(scope.f, math.matrix([
@@ -606,7 +606,7 @@ describe('parse', function () {
         ]
       ]))
 
-      assert.deepStrictEqual(parseAndEval('size(f)', scope), math.matrix([2, 2, 2]))
+      assert.deepStrictEqual(parseAndEval('size(f)', scope), [2, 2, 2])
       assert.deepStrictEqual(parseAndEval('f[:,:,1]', scope), math.matrix([[[1], [2]], [[3], [4]]]))
       assert.deepStrictEqual(parseAndEval('f[:,:,2]', scope), math.matrix([[[5], [6]], [[7], [8]]]))
       assert.deepStrictEqual(parseAndEval('f[:,2,:]', scope), math.matrix([[[2, 6]], [[4, 8]]]))
@@ -642,11 +642,11 @@ describe('parse', function () {
       assert.deepStrictEqual(parseAndEval('d=1:3', scope), math.matrix([1, 2, 3]))
       assert.deepStrictEqual(parseAndEval('concat(d,d)', scope), math.matrix([1, 2, 3, 1, 2, 3]))
       assert.deepStrictEqual(parseAndEval('e=1+d', scope), math.matrix([2, 3, 4]))
-      assert.deepStrictEqual(parseAndEval('size(e)', scope), math.matrix([3]))
+      assert.deepStrictEqual(parseAndEval('size(e)', scope), [3])
       assert.deepStrictEqual(parseAndEval('concat(e,e)', scope), math.matrix([2, 3, 4, 2, 3, 4]))
       assert.deepStrictEqual(parseAndEval('[[],[]]', scope), math.matrix([[], []]))
       assert.deepStrictEqual(parseAndEval('[[],[]]', scope).size(), [2, 0])
-      assert.deepStrictEqual(parseAndEval('size([[],[]])', scope), math.matrix([2, 0]))
+      assert.deepStrictEqual(parseAndEval('size([[],[]])', scope), [2, 0])
     })
 
     it('should disable arrays as range in a matrix index', function () {
@@ -1545,7 +1545,7 @@ describe('parse', function () {
       assert.ok(parseAndEval('[1,2,3;4,5,6]\'') instanceof Matrix)
       assert.deepStrictEqual(parseAndEval('[1:5]'), math.matrix([[1, 2, 3, 4, 5]]))
       assert.deepStrictEqual(parseAndEval('[1:5]\''), math.matrix([[1], [2], [3], [4], [5]]))
-      assert.deepStrictEqual(parseAndEval('size([1:5])'), math.matrix([1, 5]))
+      assert.deepStrictEqual(parseAndEval('size([1:5])'), [1, 5])
       assert.deepStrictEqual(parseAndEval('[1,2;3,4]\''), math.matrix([[1, 3], [2, 4]]))
     })
 
diff --git a/test/unit-tests/function/matrix/ones.test.js b/test/unit-tests/function/matrix/ones.test.js
index 6ff60c992e..b9327188e3 100644
--- a/test/unit-tests/function/matrix/ones.test.js
+++ b/test/unit-tests/function/matrix/ones.test.js
@@ -65,7 +65,7 @@ describe('ones', function () {
 
   it('should create a matrix with ones with the same size as original matrix', function () {
     const a = matrix([[1, 2, 3], [4, 5, 6]])
-    assert.deepStrictEqual(ones(math.size(a)).size(), a.size())
+    assert.deepStrictEqual(math.size(ones(math.matrix(math.size(a)))), a.size())
   })
 
   // TODO: test with invalid input
diff --git a/test/unit-tests/function/matrix/size.test.js b/test/unit-tests/function/matrix/size.test.js
index 8e7672d78b..03402a03f8 100644
--- a/test/unit-tests/function/matrix/size.test.js
+++ b/test/unit-tests/function/matrix/size.test.js
@@ -21,21 +21,21 @@ describe('size', function () {
   })
 
   it('should calculate the size of a matrix', function () {
-    assert.deepStrictEqual(size(matrix()), matrix([0]))
-    assert.deepStrictEqual(size(matrix([[1, 2, 3], [4, 5, 6]])), matrix([2, 3]))
-    assert.deepStrictEqual(size(matrix([[], []])), matrix([2, 0]))
+    assert.deepStrictEqual(size(matrix()), [0])
+    assert.deepStrictEqual(size(matrix([[1, 2, 3], [4, 5, 6]])), [2, 3])
+    assert.deepStrictEqual(size(matrix([[], []])), [2, 0])
   })
 
   it('should calculate the size of a range', function () {
-    assert.deepStrictEqual(size(math.range(2, 6)), matrix([4]))
+    assert.deepStrictEqual(size(math.range(2, 6)), [4])
   })
 
   it('should calculate the size of a scalar', function () {
-    assert.deepStrictEqual(size(2), matrix([]))
-    assert.deepStrictEqual(size(math.bignumber(2)), matrix([]))
-    assert.deepStrictEqual(size(math.complex(2, 3)), matrix([]))
-    assert.deepStrictEqual(size(true), matrix([]))
-    assert.deepStrictEqual(size(null), matrix([]))
+    assert.deepStrictEqual(size(2), [])
+    assert.deepStrictEqual(size(math.bignumber(2)), [])
+    assert.deepStrictEqual(size(math.complex(2, 3)), [])
+    assert.deepStrictEqual(size(true), [])
+    assert.deepStrictEqual(size(null), [])
   })
 
   it('should calculate the size of a scalar with setting matrix=="array"', function () {
@@ -47,8 +47,8 @@ describe('size', function () {
   })
 
   it('should calculate the size of a string', function () {
-    assert.deepStrictEqual(size('hello'), matrix([5]))
-    assert.deepStrictEqual(size(''), matrix([0]))
+    assert.deepStrictEqual(size('hello'), [5])
+    assert.deepStrictEqual(size(''), [0])
   })
 
   it('should throw an error if called with an invalid number of arguments', function () {
diff --git a/test/unit-tests/function/matrix/squeeze.test.js b/test/unit-tests/function/matrix/squeeze.test.js
index deb76d773c..6016a1b66c 100644
--- a/test/unit-tests/function/matrix/squeeze.test.js
+++ b/test/unit-tests/function/matrix/squeeze.test.js
@@ -9,14 +9,14 @@ const matrix = math.matrix
 describe('squeeze', function () {
   it('should squeeze an matrix', function () {
     let m = math.ones(matrix([1, 3, 2]))
-    assert.deepStrictEqual(size(m), matrix([1, 3, 2]))
+    assert.deepStrictEqual(size(m), [1, 3, 2])
     assert.deepStrictEqual(size(m.valueOf()), [1, 3, 2])
-    assert.deepStrictEqual(size(squeeze(m)), matrix([3, 2]))
+    assert.deepStrictEqual(size(squeeze(m)), [3, 2])
 
     m = math.ones(matrix([1, 1, 3]))
-    assert.deepStrictEqual(size(m), matrix([1, 1, 3]))
-    assert.deepStrictEqual(size(squeeze(m)), matrix([3]))
-    assert.deepStrictEqual(size(squeeze(math.range(1, 6))), matrix([5]))
+    assert.deepStrictEqual(size(m), [1, 1, 3])
+    assert.deepStrictEqual(size(squeeze(m)), [3])
+    assert.deepStrictEqual(size(squeeze(math.range(1, 6))), [5])
 
     assert.deepStrictEqual(squeeze(2.3), 2.3)
     assert.deepStrictEqual(squeeze(matrix([[5]])), 5)
diff --git a/test/unit-tests/function/matrix/zeros.test.js b/test/unit-tests/function/matrix/zeros.test.js
index b27407dea5..91ec061365 100644
--- a/test/unit-tests/function/matrix/zeros.test.js
+++ b/test/unit-tests/function/matrix/zeros.test.js
@@ -66,7 +66,7 @@ describe('zeros', function () {
 
   it('should create a matrix with zeros with the same size as original matrix', function () {
     const a = matrix([[1, 2, 3], [4, 5, 6]])
-    assert.deepStrictEqual(zeros(math.size(a)).size(), a.size())
+    assert.deepStrictEqual(math.size(zeros(math.size(a))), a.size())
   })
 
   // TODO: test with invalid input
diff --git a/test/unit-tests/type/chain/Chain.test.js b/test/unit-tests/type/chain/Chain.test.js
index f5497f082b..ca0bdd5718 100644
--- a/test/unit-tests/type/chain/Chain.test.js
+++ b/test/unit-tests/type/chain/Chain.test.js
@@ -76,7 +76,7 @@ describe('Chain', function () {
   })
 
   it('should not break with null or true as value', function () {
-    assert.deepStrictEqual(new Chain(null).size().done(), math.matrix([]))
+    assert.deepStrictEqual(new Chain(null).size().done(), [])
     assert.strictEqual(new Chain(true).add(1).done(), 2)
   })
 
diff --git a/test/unit-tests/type/matrix/function/matrix.test.js b/test/unit-tests/type/matrix/function/matrix.test.js
index 63c8a7922d..d455d82498 100644
--- a/test/unit-tests/type/matrix/function/matrix.test.js
+++ b/test/unit-tests/type/matrix/function/matrix.test.js
@@ -8,19 +8,19 @@ describe('matrix', function () {
   it('should create an empty matrix with one dimension if called without argument', function () {
     const a = matrix()
     assert.ok(a instanceof math.Matrix)
-    assert.deepStrictEqual(math.size(a), matrix([0])) // TODO: wouldn't it be nicer if an empty matrix has zero dimensions?
+    assert.deepStrictEqual(math.size(a), [0]) // TODO: wouldn't it be nicer if an empty matrix has zero dimensions?
   })
 
   it('should create empty matrix, dense format', function () {
     const a = matrix('dense')
     assert.ok(a instanceof math.Matrix)
-    assert.deepStrictEqual(math.size(a), matrix([0]))
+    assert.deepStrictEqual(math.size(a), [0])
   })
 
   it('should create empty matrix, dense format, number datatype', function () {
     const a = matrix('dense', 'number')
     assert.ok(a instanceof math.Matrix)
-    assert.deepStrictEqual(math.size(a), matrix([0]))
+    assert.deepStrictEqual(math.size(a), [0])
     assert(a.datatype(), 'number')
   })
 
@@ -33,7 +33,7 @@ describe('matrix', function () {
     const b = matrix([[1, 2], [3, 4]])
     assert.ok(b instanceof math.Matrix)
     assert.deepStrictEqual(b, matrix([[1, 2], [3, 4]]))
-    assert.deepStrictEqual(math.size(b), matrix([2, 2]))
+    assert.deepStrictEqual(math.size(b), [2, 2])
   })
 
   it('should be the identity if called with a matrix, dense format', function () {
@@ -41,7 +41,7 @@ describe('matrix', function () {
     const c = matrix(b, 'dense')
     assert.ok(c._data !== b._data) // data should be cloned
     assert.deepStrictEqual(c, matrix([[1, 2], [3, 4]], 'dense'))
-    assert.deepStrictEqual(math.size(c), matrix([2, 2], 'dense'))
+    assert.deepStrictEqual(math.size(c), [2, 2])
   })
 
   it('should be the identity if called with a matrix, dense format, number datatype', function () {
@@ -73,7 +73,7 @@ describe('matrix', function () {
     const d = matrix(math.range(1, 6))
     assert.ok(d instanceof math.Matrix)
     assert.deepStrictEqual(d, matrix([1, 2, 3, 4, 5]))
-    assert.deepStrictEqual(math.size(d), matrix([5]))
+    assert.deepStrictEqual(math.size(d), [5])
   })
 
   it('should throw an error if called with an invalid argument', function () {