diff --git a/src/UglyToad.PdfPig.Tests/Integration/SinglePageFormContentIText1Tests.cs b/src/UglyToad.PdfPig.Tests/Integration/SinglePageFormContentIText1Tests.cs
index 4e6719c1..6d7cc9d9 100644
--- a/src/UglyToad.PdfPig.Tests/Integration/SinglePageFormContentIText1Tests.cs
+++ b/src/UglyToad.PdfPig.Tests/Integration/SinglePageFormContentIText1Tests.cs
@@ -1,6 +1,7 @@
 namespace UglyToad.PdfPig.Tests.Integration
 {
     using System;
+    using System.Globalization;
     using System.IO;
     using System.Linq;
     using Content;
@@ -63,7 +64,10 @@
                 {
                     var stripped = x.Trim();
                     var parts = stripped.Split('|');
-                    return (index: int.Parse(parts[0]), letter: parts[1], x: double.Parse(parts[2]), y: double.Parse(parts[3]));
+                    var index = int.Parse(parts[0]);
+                    var xval = double.Parse(parts[2], CultureInfo.InvariantCulture);
+                    var yval = double.Parse(parts[3], CultureInfo.InvariantCulture);
+                    return (index, letter: parts[1], x: xval, y: yval);
                 }).ToArray();
 
             using (var document = PdfDocument.Open(GetFilename()))
diff --git a/src/UglyToad.PdfPig.Tests/Tokenization/ArrayTokenizerTests.cs b/src/UglyToad.PdfPig.Tests/Tokenization/ArrayTokenizerTests.cs
index 45d70fa6..43aec37a 100644
--- a/src/UglyToad.PdfPig.Tests/Tokenization/ArrayTokenizerTests.cs
+++ b/src/UglyToad.PdfPig.Tests/Tokenization/ArrayTokenizerTests.cs
@@ -1,7 +1,6 @@
 namespace UglyToad.PdfPig.Tests.Tokenization
 {
     using System.Collections.Generic;
-    using System.Threading;
     using PdfPig.Tokenization;
     using PdfPig.Tokens;
     using Xunit;
@@ -18,7 +17,6 @@
         [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/Graphics/Operations/OperationWriteHelper.cs b/src/UglyToad.PdfPig/Graphics/Operations/OperationWriteHelper.cs
index e236feff..c4ca203c 100644
--- a/src/UglyToad.PdfPig/Graphics/Operations/OperationWriteHelper.cs
+++ b/src/UglyToad.PdfPig/Graphics/Operations/OperationWriteHelper.cs
@@ -1,6 +1,7 @@
 namespace UglyToad.PdfPig.Graphics.Operations
 {
     using System;
+    using System.Globalization;
     using System.IO;
     using PdfPig.Core;
 
@@ -37,7 +38,7 @@
 
         public static void WriteDecimal(this Stream stream, decimal value)
         {
-            stream.WriteText(value.ToString("G"));
+            stream.WriteText(value.ToString("G", CultureInfo.InvariantCulture));
         }
 
         public static void WriteNumberText(this Stream stream, decimal number, string text)
diff --git a/src/UglyToad.PdfPig/Graphics/Operations/TextState/SetFontAndSize.cs b/src/UglyToad.PdfPig/Graphics/Operations/TextState/SetFontAndSize.cs
index bf953f05..6b1efc08 100644
--- a/src/UglyToad.PdfPig/Graphics/Operations/TextState/SetFontAndSize.cs
+++ b/src/UglyToad.PdfPig/Graphics/Operations/TextState/SetFontAndSize.cs
@@ -1,6 +1,7 @@
 namespace UglyToad.PdfPig.Graphics.Operations.TextState
 {
     using System;
+    using System.Globalization;
     using System.IO;
     using Tokens;
     using Util.JetBrains.Annotations;
@@ -64,7 +65,7 @@
         /// <inheritdoc />
         public override string ToString()
         {
-            return $"{Font} {Size} {Symbol}";
+            return $"{Font} {Size.ToString("G", CultureInfo.InvariantCulture)} {Symbol}";
         }
     }
 }
\ No newline at end of file
diff --git a/src/UglyToad.PdfPig/Writer/PdfStreamWriter.cs b/src/UglyToad.PdfPig/Writer/PdfStreamWriter.cs
index d4b7f038..9e25b16d 100644
--- a/src/UglyToad.PdfPig/Writer/PdfStreamWriter.cs
+++ b/src/UglyToad.PdfPig/Writer/PdfStreamWriter.cs
@@ -2,6 +2,7 @@
 {
     using System;
     using System.Collections.Generic;
+    using System.Globalization;
     using System.IO;
     using Core;
     using Graphics.Operations;
@@ -35,7 +36,7 @@
             if (catalogReference == null)
                 throw new ArgumentNullException(nameof(catalogReference));
             
-            WriteString($"%PDF-{version:0.0}", Stream);
+            WriteString($"%PDF-{version.ToString("0.0", CultureInfo.InvariantCulture)}", Stream);
 
             Stream.WriteText("%");
             Stream.WriteByte(169);