diff --git a/Flow.Launcher.Test/Plugins/CalculatorTest.cs b/Flow.Launcher.Test/Plugins/CalculatorTest.cs
index 4e40d3645b0..58217d9320d 100644
--- a/Flow.Launcher.Test/Plugins/CalculatorTest.cs
+++ b/Flow.Launcher.Test/Plugins/CalculatorTest.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Reflection;
 using Flow.Launcher.Plugin.Calculator;
@@ -114,6 +114,10 @@ public void ThousandsSeparatorTest_LargeNumber()
         [TestCase(@"sqrt(-1)", "")]
         [TestCase(@"log(0)", "")]
         [TestCase(@"invalid_expression", "")]
+        // Floating point precision
+        [TestCase(@"3000000-2911111.82", "88888.18")]
+        [TestCase(@"123456789012345", "123456789012345")]
+        [TestCase(@"9007199254740991", "9007199254740991")]
         public void CalculatorTest(string expression, string result)
         {
             _settings.UseThousandsSeparator = false;
diff --git a/Plugins/Flow.Launcher.Plugin.Calculator/Main.cs b/Plugins/Flow.Launcher.Plugin.Calculator/Main.cs
index 1b9a38e1819..62e12f9b6cd 100644
--- a/Plugins/Flow.Launcher.Plugin.Calculator/Main.cs
+++ b/Plugins/Flow.Launcher.Plugin.Calculator/Main.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
@@ -128,7 +128,18 @@ public List<Result> Query(Query query)
 
                 if (!string.IsNullOrEmpty(result.ToString()))
                 {
-                    decimal roundedResult = Math.Round(Convert.ToDecimal(result), _settings.MaxDecimalPlaces, MidpointRounding.AwayFromZero);
+                    double rawValue = Convert.ToDouble(result);
+                    decimal decValue;
+                    if (double.IsNaN(rawValue) || double.IsInfinity(rawValue))
+                    {
+                        decValue = (decimal)rawValue;
+                    }
+                    else
+                    {
+                        string format = (rawValue % 1 == 0) ? "G17" : "G14";
+                        decValue = decimal.Parse(rawValue.ToString(format, CultureInfo.InvariantCulture), NumberStyles.Any, CultureInfo.InvariantCulture);
+                    }
+                    decimal roundedResult = Math.Round(decValue, _settings.MaxDecimalPlaces, MidpointRounding.AwayFromZero);
                     string newResult = FormatResult(roundedResult);
 
                     return
@@ -138,7 +149,6 @@ public List<Result> Query(Query query)
                             Title = newResult,
                             IcoPath = IcoPath,
                             Score = 300,
-                            // Check context nullability for unit testing
                             SubTitle = Context == null ? string.Empty : Localize.flowlauncher_plugin_calculator_copy_number_to_clipboard(),
                             CopyText = newResult,
                             Action = c =>