diff --git a/src/UglyToad.PdfPig.Core/PdfPoint.cs b/src/UglyToad.PdfPig.Core/PdfPoint.cs
index 7955c8ad..60fc5f9b 100644
--- a/src/UglyToad.PdfPig.Core/PdfPoint.cs
+++ b/src/UglyToad.PdfPig.Core/PdfPoint.cs
@@ -1,6 +1,7 @@
 namespace UglyToad.PdfPig.Core
 {
     using System.Diagnostics;
+    using System.Globalization;
 
     /// <summary>
     /// A point in a PDF file. 
@@ -112,7 +113,7 @@
         /// <inheritdoc />
         public override string ToString()
         {
-            return $"(x:{X}, y:{Y})";
+            return $"(x:{X.ToString(CultureInfo.InvariantCulture)}, y:{Y.ToString(CultureInfo.InvariantCulture)})";
         }
     }
 }
diff --git a/src/UglyToad.PdfPig.Core/PdfRectangle.cs b/src/UglyToad.PdfPig.Core/PdfRectangle.cs
index 808b1d48..41562c90 100644
--- a/src/UglyToad.PdfPig.Core/PdfRectangle.cs
+++ b/src/UglyToad.PdfPig.Core/PdfRectangle.cs
@@ -1,6 +1,7 @@
 namespace UglyToad.PdfPig.Core
 {
     using System;
+    using System.Globalization;
 
     /// <summary>
     /// A rectangle in a PDF file. 
@@ -208,7 +209,7 @@
         /// <inheritdoc />
         public override string ToString()
         {
-            return $"[{TopLeft}, {Width}, {Height}]";
+            return $"[{TopLeft}, {Width.ToString(CultureInfo.InvariantCulture)}, {Height.ToString(CultureInfo.InvariantCulture)}]";
         }
     }
 }
diff --git a/src/UglyToad.PdfPig.Fonts/CompactFontFormat/CharStrings/Type2CharStrings.cs b/src/UglyToad.PdfPig.Fonts/CompactFontFormat/CharStrings/Type2CharStrings.cs
index 78ec81ec..f60b409b 100644
--- a/src/UglyToad.PdfPig.Fonts/CompactFontFormat/CharStrings/Type2CharStrings.cs
+++ b/src/UglyToad.PdfPig.Fonts/CompactFontFormat/CharStrings/Type2CharStrings.cs
@@ -2,6 +2,7 @@
 {
     using System;
     using System.Collections.Generic;
+    using System.Globalization;
     using System.Text;
     using Core;
 
@@ -184,7 +185,7 @@
                     if (i >= 0)
                     {
                         var value = Values[i];
-                        stringBuilder.AppendLine(value.ToString("N"));
+                        stringBuilder.AppendLine(value.ToString("N", CultureInfo.InvariantCulture));
                     }
 
                     foreach (var identifier in GetCommandsAt(i + 1))
diff --git a/src/UglyToad.PdfPig.Fonts/Type1/CharStrings/Type1CharstringDecryptedBytes.cs b/src/UglyToad.PdfPig.Fonts/Type1/CharStrings/Type1CharstringDecryptedBytes.cs
index b1ec7b57..3827d4cf 100644
--- a/src/UglyToad.PdfPig.Fonts/Type1/CharStrings/Type1CharstringDecryptedBytes.cs
+++ b/src/UglyToad.PdfPig.Fonts/Type1/CharStrings/Type1CharstringDecryptedBytes.cs
@@ -2,6 +2,7 @@
 {
     using System;
     using System.Collections.Generic;
+    using System.Globalization;
 
     internal class Type1CharstringDecryptedBytes
     {
@@ -25,7 +26,7 @@
         {
             Bytes = bytes ?? throw new ArgumentNullException(nameof(bytes));
             Index = index;
-            Name = name ?? index.ToString();
+            Name = name ?? index.ToString(CultureInfo.InvariantCulture);
             Source = SourceType.Charstring;
         }
 
diff --git a/src/UglyToad.PdfPig.Tests/Tokenization/ArrayTokenizerTests.cs b/src/UglyToad.PdfPig.Tests/Tokenization/ArrayTokenizerTests.cs
index 43aec37a..45d70fa6 100644
--- a/src/UglyToad.PdfPig.Tests/Tokenization/ArrayTokenizerTests.cs
+++ b/src/UglyToad.PdfPig.Tests/Tokenization/ArrayTokenizerTests.cs
@@ -1,6 +1,7 @@
 namespace UglyToad.PdfPig.Tests.Tokenization
 {
     using System.Collections.Generic;
+    using System.Threading;
     using PdfPig.Tokenization;
     using PdfPig.Tokens;
     using Xunit;
@@ -17,6 +18,7 @@
         [InlineData("\0")]
         public void InvalidFirstCharacter_ReturnsFalse(string s)
         {
+            var cult =  Thread.CurrentThread.CurrentCulture;
             var input = StringBytesTestConverter.Convert(s);
 
             var result = tokenizer.TryTokenize(input.First, input.Bytes, out var token);
diff --git a/src/UglyToad.PdfPig/Content/PageRotationDegrees.cs b/src/UglyToad.PdfPig/Content/PageRotationDegrees.cs
index 571cc408..261e9b8f 100644
--- a/src/UglyToad.PdfPig/Content/PageRotationDegrees.cs
+++ b/src/UglyToad.PdfPig/Content/PageRotationDegrees.cs
@@ -1,14 +1,12 @@
 namespace UglyToad.PdfPig.Content
 {
     using System;
-    using System.Diagnostics.Contracts;
-    using Core;
-    using Geometry;
+    using System.Globalization;
 
     /// <summary>
     /// Represents the rotation of a page in a PDF document defined by the page dictionary in degrees clockwise.
     /// </summary>
-    public struct PageRotationDegrees : IEquatable<PageRotationDegrees>
+    public readonly struct PageRotationDegrees : IEquatable<PageRotationDegrees>
     {
         /// <summary>
         /// The rotation of the page in degrees clockwise.
@@ -76,7 +74,7 @@
         /// <inheritdoc />
         public override string ToString()
         {
-            return Value.ToString();
+            return Value.ToString(CultureInfo.InvariantCulture);
         }
 
         /// <inheritdoc />
diff --git a/src/UglyToad.PdfPig/Geometry/UserSpaceUnit.cs b/src/UglyToad.PdfPig/Geometry/UserSpaceUnit.cs
index ba40c6a7..65f15a22 100644
--- a/src/UglyToad.PdfPig/Geometry/UserSpaceUnit.cs
+++ b/src/UglyToad.PdfPig/Geometry/UserSpaceUnit.cs
@@ -1,12 +1,13 @@
 namespace UglyToad.PdfPig.Geometry
 {
     using System;
+    using System.Globalization;
 
     /// <summary>
     /// By default user space units correspond to 1/72nd of an inch (a typographic point).
     /// The UserUnit entry in a page dictionary can define the space units as a different multiple of 1/72 (1 point).
     /// </summary>
-    internal struct UserSpaceUnit
+    internal readonly struct UserSpaceUnit
     {
         public static readonly UserSpaceUnit Default = new UserSpaceUnit(1);
 
@@ -30,7 +31,7 @@
 
         public override string ToString()
         {
-            return PointMultiples.ToString();
+            return PointMultiples.ToString(CultureInfo.InvariantCulture);
         }
     }
 }
diff --git a/src/UglyToad.PdfPig/PdfFonts/CharacterIdentifierSystemInfo.cs b/src/UglyToad.PdfPig/PdfFonts/CharacterIdentifierSystemInfo.cs
index a7def673..2ccbb64e 100644
--- a/src/UglyToad.PdfPig/PdfFonts/CharacterIdentifierSystemInfo.cs
+++ b/src/UglyToad.PdfPig/PdfFonts/CharacterIdentifierSystemInfo.cs
@@ -1,11 +1,12 @@
 namespace UglyToad.PdfPig.PdfFonts
 {
+    using System.Globalization;
     using CidFonts;
 
     /// <summary>
     /// Specifies the character collection associated with the <see cref="ICidFont"/> (CIDFont).
     /// </summary>
-    internal struct CharacterIdentifierSystemInfo
+    internal readonly struct CharacterIdentifierSystemInfo
     {
         /// <summary>
         /// Identifies the issuer of the character collection.
@@ -31,7 +32,7 @@
 
         public override string ToString()
         {
-            return $"{Registry}-{Ordering}-{Supplement}";
+            return $"{Registry}-{Ordering}-{Supplement.ToString(CultureInfo.InvariantCulture)}";
         }
     }
 }
\ No newline at end of file
diff --git a/src/UglyToad.PdfPig/PdfFonts/Parser/Handlers/TrueTypeFontHandler.cs b/src/UglyToad.PdfPig/PdfFonts/Parser/Handlers/TrueTypeFontHandler.cs
index d030262a..aa887dbe 100644
--- a/src/UglyToad.PdfPig/PdfFonts/Parser/Handlers/TrueTypeFontHandler.cs
+++ b/src/UglyToad.PdfPig/PdfFonts/Parser/Handlers/TrueTypeFontHandler.cs
@@ -2,6 +2,7 @@
 {
     using System;
     using System.Collections.Generic;
+    using System.Globalization;
     using System.Linq;
     using Cmap;
     using Core;
@@ -136,7 +137,7 @@
                         }
                         else
                         {
-                            glyphName = index.ToString();
+                            glyphName = index.ToString(CultureInfo.InvariantCulture);
                         }
 
                         fakeEncoding[i] = glyphName;