diff --git a/src/base58.coffee b/src/base58.coffee
index 6fff825..aeeddf3 100644
--- a/src/base58.coffee
+++ b/src/base58.coffee
@@ -5,6 +5,7 @@ class Base58Builder
 
   encode: (num) ->
     throw new Error('Value passed is not an integer.') unless /^\d+$/.test num
+    num = parseInt(num) unless typeof num == 'number'
     str = ''
     while num >= @base
       mod = num % @base
diff --git a/test/base58_test.coffee b/test/base58_test.coffee
index 3af1d9a..78a0eb7 100644
--- a/test/base58_test.coffee
+++ b/test/base58_test.coffee
@@ -10,6 +10,11 @@ describe 'Base58', ->
       for str, num of examples
         Base58.encode(num).should.eql(str)
 
+    describe 'when passed a string only containing numbers', ->
+      it 'encodes string after first converting it to an integer', ->
+        for str, num of examples
+          Base58.encode(num.toString()).should.eql(str)
+
     describe 'when passed a float', ->
       it 'throws an error', ->
         (-> Base58.encode(3.14)).should