diff --git a/lib/function/string/format.js b/lib/function/string/format.js
index 5ad15b450..a20773530 100644
--- a/lib/function/string/format.js
+++ b/lib/function/string/format.js
@@ -38,10 +38,10 @@ function factory (type, config, load, typed) {
    *    - `precision: number`
    *      A number between 0 and 16 to round the digits of the number. In case
    *      of notations 'exponential' and 'auto', `precision` defines the total
-   *      number of significant digits returned and is undefined by default.
+   *      number of significant digits returned.
    *      In case of notation 'fixed', `precision` defines the number of
-   *      significant digits after the decimal point, and is undefined by default,
-   *      not rounding any digits.
+   *      significant digits after the decimal point.
+   *      `precision` is undefined by default.
    *    - `exponential: Object`
    *      An object containing two parameters, {number} lower and {number} upper,
    *      used by notation 'auto' to determine when to return exponential
diff --git a/lib/utils/bignumber/formatter.js b/lib/utils/bignumber/formatter.js
index 664625ec5..29f9a2795 100644
--- a/lib/utils/bignumber/formatter.js
+++ b/lib/utils/bignumber/formatter.js
@@ -29,14 +29,12 @@
  *                                          the digits of the number.
  *                                          In case of notations 'exponential' and
  *                                          'auto', `precision` defines the total
- *                                          number of significant digits returned
- *                                          and is undefined by default.
+ *                                          number of significant digits returned.
  *                                          In case of notation 'fixed',
  *                                          `precision` defines the number of
  *                                          significant digits after the decimal 
- *                                          point, and is undefined by default,
- *                                          not rounding any digits.
- *                                          point, and is 0 by default.
+ *                                          point. 
+ *                                          `precision` is undefined by default.
  *                     {Object} exponential An object containing two parameters,
  *                                          {number} lower and {number} upper,
  *                                          used by notation 'auto' to determine
@@ -176,11 +174,9 @@ exports.toExponential = function (value, precision) {
 /**
  * Format a number with fixed notation.
  * @param {BigNumber} value
- * @param {number} [precision=0]        Optional number of decimals after the
- *                                      decimal point. Zero by default.
+ * @param {number} [precision=undefined] Optional number of decimals after the
+ *                                       decimal point. Undefined by default.
  */
 exports.toFixed = function (value, precision) {
-  return value.toFixed(precision || 0);
-  // Note: the (precision || 0) is needed as the toFixed of BigNumber has an
-  // undefined default precision instead of 0.
+  return value.toFixed(precision);
 };
diff --git a/lib/utils/number.js b/lib/utils/number.js
index 3d4097aed..3a5c791e5 100644
--- a/lib/utils/number.js
+++ b/lib/utils/number.js
@@ -75,14 +75,13 @@ exports.sign = Math.sign || function(x) {
  *                                          the digits of the number.
  *                                          In case of notations 'exponential' and
  *                                          'auto', `precision` defines the total
- *                                          number of significant digits returned
- *                                          and is undefined by default.
+ *                                          number of significant digits returned.
  *                                          In case of notation 'fixed',
  *                                          `precision` defines the number of
  *                                          significant digits after the decimal 
- *                                          point, and is undefined by default,
+ *                                          point.
+ *                                          `precision` is undefined by default,
  *                                          not rounding any digits.
- *                                          point, and is 0 by default.
  *                     {Object} exponential An object containing two parameters,
  *                                          {number} lower and {number} upper,
  *                                          used by notation 'auto' to determine
diff --git a/test/utils/bignumber/formatter.test.js b/test/utils/bignumber/formatter.test.js
index b35ead661..f1e906e97 100644
--- a/test/utils/bignumber/formatter.test.js
+++ b/test/utils/bignumber/formatter.test.js
@@ -189,8 +189,8 @@ describe('format', function () {
         notation: 'fixed'
       };
 
-      assert.deepEqual(formatter.format(new BigNumber('1.23456'), options), '1');
-      assert.deepEqual(formatter.format(new BigNumber('1.7'), options), '2');
+      assert.deepEqual(formatter.format(new BigNumber('1.23456'), options), '1.23456');
+      assert.deepEqual(formatter.format(new BigNumber('1.7'), options), '1.7');
       assert.deepEqual(formatter.format(new BigNumber('12345678'), options), '12345678');
       assert.deepEqual(formatter.format(new BigNumber('12e18'), options), '12000000000000000000');
       assert.deepEqual(formatter.format(new BigNumber('12e30'), options), '12000000000000000000000000000000');
@@ -219,7 +219,7 @@ describe('format', function () {
   it('should format a bignumber using toFixed', function() {
     var Big = BigNumber.clone({precision: 100});
 
-    assert.equal(formatter.toFixed(new Big(2.34)), '2');
+    assert.equal(formatter.toFixed(new Big(2.34)), '2.34');
     assert.equal(formatter.toFixed(new Big(2.34), 1), '2.3');
     assert.equal(formatter.toFixed(new Big(2), 20), '2.00000000000000000000');
     assert.equal(formatter.toFixed(new Big(2), 21), '2.000000000000000000000');