diff --git a/ClosedXML/Excel/CalcEngine/Functions/MathTrig.cs b/ClosedXML/Excel/CalcEngine/Functions/MathTrig.cs
index eac01ce..72401fd 100644
--- a/ClosedXML/Excel/CalcEngine/Functions/MathTrig.cs
+++ b/ClosedXML/Excel/CalcEngine/Functions/MathTrig.cs
@@ -19,6 +19,7 @@
             ce.RegisterFunction("ACOSH", 1, Acosh);
             ce.RegisterFunction("ACOT", 1, Acot);
             ce.RegisterFunction("ACOTH", 1, Acoth);
+            ce.RegisterFunction("ARABIC", 1, Arabic);
             ce.RegisterFunction("ASIN", 1, Asin);
             ce.RegisterFunction("ASINH", 1, Asinh);
             ce.RegisterFunction("ATAN", 1, Atan);
@@ -516,6 +517,31 @@
             return 0.5 * Math.Log((number + 1) / (number - 1));
         }
 
+        private static object Arabic(List<Expression> p)
+        {
+            string input = ((string)p[0]).Trim();
+
+            try
+            {
+                if (input == "")
+                    return 0;
+                if (input == "-")
+                    throw new NumberException();
+                else if (input[0] == '-')
+                    return -XLMath.RomanToArabic(input.Substring(1));
+                else
+                    return XLMath.RomanToArabic(input);
+            }
+            catch (ArgumentOutOfRangeException)
+            {
+                throw new CellValueException();
+            }
+            catch
+            {
+                throw;
+            }
+        }
+
         private static object Asinh(List<Expression> p)
         {
             return XLMath.ASinh(p[0]);
diff --git a/ClosedXML/Excel/CalcEngine/Functions/XLMath.cs b/ClosedXML/Excel/CalcEngine/Functions/XLMath.cs
index 693f68f..85f5fe2 100644
--- a/ClosedXML/Excel/CalcEngine/Functions/XLMath.cs
+++ b/ClosedXML/Excel/CalcEngine/Functions/XLMath.cs
@@ -118,5 +118,38 @@
             throw new ArgumentOutOfRangeException("something bad happened");
         }
 
+        public static int RomanToArabic(string text)
+        {
+            if (text == "")
+                return 0;
+            if (text.StartsWith("M", StringComparison.InvariantCultureIgnoreCase))
+                return 1000 + RomanToArabic(text.Substring(1));
+            if (text.StartsWith("CM", StringComparison.InvariantCultureIgnoreCase))
+                return 900 + RomanToArabic(text.Substring(2));
+            if (text.StartsWith("D", StringComparison.InvariantCultureIgnoreCase))
+                return 500 + RomanToArabic(text.Substring(1));
+            if (text.StartsWith("CD", StringComparison.InvariantCultureIgnoreCase))
+                return 400 + RomanToArabic(text.Substring(2));
+            if (text.StartsWith("C", StringComparison.InvariantCultureIgnoreCase))
+                return 100 + RomanToArabic(text.Substring(1));
+            if (text.StartsWith("XC", StringComparison.InvariantCultureIgnoreCase))
+                return 90 + RomanToArabic(text.Substring(2));
+            if (text.StartsWith("L", StringComparison.InvariantCultureIgnoreCase))
+                return 50 + RomanToArabic(text.Substring(1));
+            if (text.StartsWith("XL", StringComparison.InvariantCultureIgnoreCase))
+                return 40 + RomanToArabic(text.Substring(2));
+            if (text.StartsWith("X", StringComparison.InvariantCultureIgnoreCase))
+                return 10 + RomanToArabic(text.Substring(1));
+            if (text.StartsWith("IX", StringComparison.InvariantCultureIgnoreCase))
+                return 9 + RomanToArabic(text.Substring(2));
+            if (text.StartsWith("V", StringComparison.InvariantCultureIgnoreCase))
+                return 5 + RomanToArabic(text.Substring(1));
+            if (text.StartsWith("IV", StringComparison.InvariantCultureIgnoreCase))
+                return 4 + RomanToArabic(text.Substring(2));
+            if (text.StartsWith("I", StringComparison.InvariantCultureIgnoreCase))
+                return 1 + RomanToArabic(text.Substring(1));
+            
+            throw new ArgumentOutOfRangeException("text is not a valid roman number");
+        }
     }
 }
diff --git a/ClosedXML_Tests/Excel/CalcEngine/MathTrigTests.cs b/ClosedXML_Tests/Excel/CalcEngine/MathTrigTests.cs
index 1152e62..0165213 100644
--- a/ClosedXML_Tests/Excel/CalcEngine/MathTrigTests.cs
+++ b/ClosedXML_Tests/Excel/CalcEngine/MathTrigTests.cs
@@ -148,6 +148,31 @@
             Assert.Throws<NumberException>(() => XLWorkbook.EvaluateExpr(string.Format(@"ACOTH({0})", input.ToString(CultureInfo.InvariantCulture))));
         }
 
+        [TestCase("LVII", 57)]
+        [TestCase("mcmxii", 1912)]
+        [TestCase("", 0)]
+        [TestCase("-IV", -4)]
+        [TestCase("   XIV", 14)]
+        [TestCase("MCMLXXXIII ", 1983)]
+        public void Arabic_ReturnsCorrectNumber(string roman, int arabic)
+        {
+            var actual = (int)XLWorkbook.EvaluateExpr(string.Format($"ARABIC(\"{roman}\")"));
+            Assert.AreEqual(arabic, actual);
+        }
+
+        [Test]
+        public void Arabic_ThrowsNumberExceptionOnMinus()
+        {
+            Assert.Throws<NumberException>(() => XLWorkbook.EvaluateExpr("ARABIC(\"-\")"));
+        }
+
+        [TestCase("- I")]
+        [TestCase("roman")]
+        public void Arabic_ThrowsValueExceptionOnInvalidNumber(string invalidRoman)
+        {
+            Assert.Throws<CellValueException>(() => XLWorkbook.EvaluateExpr($"ARABIC(\"{invalidRoman}\")"));
+        }
+
         [TestCase(4, 3, 20)]
         [TestCase(10, 3, 220)]
         [TestCase(0, 0, 1)]