diff --git a/src/SMAPI.Tests/Core/PathUtilitiesTests.cs b/src/SMAPI.Tests/Core/PathUtilitiesTests.cs
new file mode 100644
index 00000000..268ba504
--- /dev/null
+++ b/src/SMAPI.Tests/Core/PathUtilitiesTests.cs
@@ -0,0 +1,70 @@
+using NUnit.Framework;
+using StardewModdingAPI.Framework.Utilities;
+
+namespace StardewModdingAPI.Tests.Core
+{
+    /// <summary>Unit tests for <see cref="PathUtilities"/>.</summary>
+    [TestFixture]
+    public class PathUtilitiesTests
+    {
+        /*********
+        ** Unit tests
+        *********/
+        [Test(Description = "Assert that GetSegments returns the expected values.")]
+        [TestCase("", ExpectedResult = "")]
+        [TestCase("/", ExpectedResult = "")]
+        [TestCase("///", ExpectedResult = "")]
+        [TestCase("/usr/bin", ExpectedResult = "usr|bin")]
+        [TestCase("/usr//bin//", ExpectedResult = "usr|bin")]
+        [TestCase("/usr//bin//.././boop.exe", ExpectedResult = "usr|bin|..|.|boop.exe")]
+        [TestCase(@"C:", ExpectedResult = "C:")]
+        [TestCase(@"C:/boop", ExpectedResult = "C:|boop")]
+        [TestCase(@"C:\boop\/usr//bin//.././boop.exe", ExpectedResult = "C:|boop|usr|bin|..|.|boop.exe")]
+        public string GetSegments(string path)
+        {
+            return string.Join("|", PathUtilities.GetSegments(path));
+        }
+
+        [Test(Description = "Assert that NormalisePathSeparators returns the expected values.")]
+#if SMAPI_FOR_WINDOWS
+        [TestCase("", ExpectedResult = "")]
+        [TestCase("/", ExpectedResult = "")]
+        [TestCase("///", ExpectedResult = "")]
+        [TestCase("/usr/bin", ExpectedResult = @"usr\bin")]
+        [TestCase("/usr//bin//", ExpectedResult = @"usr\bin")]
+        [TestCase("/usr//bin//.././boop.exe", ExpectedResult = @"usr\bin\..\.\boop.exe")]
+        [TestCase("C:", ExpectedResult = "C:")]
+        [TestCase("C:/boop", ExpectedResult = @"C:\boop")]
+        [TestCase(@"C:\usr\bin//.././boop.exe", ExpectedResult = @"C:\usr\bin\..\.\boop.exe")]
+#else
+        [TestCase("", ExpectedResult = "")]
+        [TestCase("/", ExpectedResult = "/")]
+        [TestCase("///", ExpectedResult = "/")]
+        [TestCase("/usr/bin", ExpectedResult = "/usr/bin")]
+        [TestCase("/usr//bin//", ExpectedResult = "/usr/bin")]
+        [TestCase("/usr//bin//.././boop.exe", ExpectedResult = "/usr/bin/.././boop.exe")]
+        [TestCase("C:", ExpectedResult = "C:")]
+        [TestCase("C:/boop", ExpectedResult = "C:/boop")]
+        [TestCase(@"C:\usr\bin//.././boop.exe", ExpectedResult = "C:/usr/bin/.././boop.exe")]
+#endif
+        public string NormalisePathSeparators(string path)
+        {
+            return PathUtilities.NormalisePathSeparators(path);
+        }
+
+        [Test(Description = "Assert that GetRelativePath returns the expected values.")]
+#if SMAPI_FOR_WINDOWS
+        [TestCase(@"C:\", @"C:\", ExpectedResult = "./")]
+        [TestCase(@"C:\grandparent\parent\child", @"C:\grandparent\parent\sibling", ExpectedResult = @"..\sibling")]
+        [TestCase(@"C:\grandparent\parent\child", @"C:\cousin\file.exe", ExpectedResult = @"..\..\..\cousin\file.exe")]
+#else
+        [TestCase("/", "/", ExpectedResult = "./")]
+        [TestCase("/grandparent/parent/child", "/grandparent/parent/sibling", ExpectedResult = "../sibling")]
+        [TestCase("/grandparent/parent/child", "/cousin/file.exe", ExpectedResult = "../../../cousin/file.exe")]
+#endif
+        public string GetRelativePath(string sourceDir, string targetPath)
+        {
+            return PathUtilities.GetRelativePath(sourceDir, targetPath);
+        }
+    }
+}
diff --git a/src/SMAPI.Tests/StardewModdingAPI.Tests.csproj b/src/SMAPI.Tests/StardewModdingAPI.Tests.csproj
index 6e7fa1f0..e4b2c8c6 100644
--- a/src/SMAPI.Tests/StardewModdingAPI.Tests.csproj
+++ b/src/SMAPI.Tests/StardewModdingAPI.Tests.csproj
@@ -49,6 +49,7 @@
     <Compile Include="..\..\build\GlobalAssemblyInfo.cs">
       <Link>Properties\GlobalAssemblyInfo.cs</Link>
     </Compile>
+    <Compile Include="Core\PathUtilitiesTests.cs" />
     <Compile Include="Utilities\SemanticVersionTests.cs" />
     <Compile Include="Utilities\SDateTests.cs" />
     <Compile Include="Core\TranslationTests.cs" />
diff --git a/src/SMAPI/Framework/Content/ContentCache.cs b/src/SMAPI/Framework/Content/ContentCache.cs
index 4508e641..533da398 100644
--- a/src/SMAPI/Framework/Content/ContentCache.cs
+++ b/src/SMAPI/Framework/Content/ContentCache.cs
@@ -5,6 +5,7 @@ using System.Linq;
 using Microsoft.Xna.Framework;
 using StardewModdingAPI.Framework.ModLoading;
 using StardewModdingAPI.Framework.Reflection;
+using StardewModdingAPI.Framework.Utilities;
 using StardewValley;
 
 namespace StardewModdingAPI.Framework.Content
@@ -18,12 +19,6 @@ namespace StardewModdingAPI.Framework.Content
         /// <summary>The underlying asset cache.</summary>
         private readonly IDictionary<string, object> Cache;
 
-        /// <summary>The possible directory separator characters in an asset key.</summary>
-        private readonly char[] PossiblePathSeparators;
-
-        /// <summary>The preferred directory separator chaeacter in an asset key.</summary>
-        private readonly string PreferredPathSeparator;
-
         /// <summary>Applies platform-specific asset key normalisation so it's consistent with the underlying cache.</summary>
         private readonly Func<string, string> NormaliseAssetNameForPlatform;
 
@@ -52,14 +47,10 @@ namespace StardewModdingAPI.Framework.Content
         /// <summary>Construct an instance.</summary>
         /// <param name="contentManager">The underlying content manager whose cache to manage.</param>
         /// <param name="reflection">Simplifies access to private game code.</param>
-        /// <param name="possiblePathSeparators">The possible directory separator characters in an asset key.</param>
-        /// <param name="preferredPathSeparator">The preferred directory separator chaeacter in an asset key.</param>
-        public ContentCache(LocalizedContentManager contentManager, Reflector reflection, char[] possiblePathSeparators, string preferredPathSeparator)
+        public ContentCache(LocalizedContentManager contentManager, Reflector reflection)
         {
             // init
             this.Cache = reflection.GetField<Dictionary<string, object>>(contentManager, "loadedAssets").GetValue();
-            this.PossiblePathSeparators = possiblePathSeparators;
-            this.PreferredPathSeparator = preferredPathSeparator;
 
             // get key normalisation logic
             if (Constants.TargetPlatform == Platform.Windows)
@@ -90,11 +81,7 @@ namespace StardewModdingAPI.Framework.Content
         [Pure]
         public string NormalisePathSeparators(string path)
         {
-            string[] parts = path.Split(this.PossiblePathSeparators, StringSplitOptions.RemoveEmptyEntries);
-            string normalised = string.Join(this.PreferredPathSeparator, parts);
-            if (path.StartsWith(this.PreferredPathSeparator))
-                normalised = this.PreferredPathSeparator + normalised; // keep root slash
-            return normalised;
+            return PathUtilities.NormalisePathSeparators(path);
         }
 
         /// <summary>Normalise a cache key so it's consistent with the underlying cache.</summary>
diff --git a/src/SMAPI/Framework/ModHelpers/ContentHelper.cs b/src/SMAPI/Framework/ModHelpers/ContentHelper.cs
index 4a1d3853..7d8bec1e 100644
--- a/src/SMAPI/Framework/ModHelpers/ContentHelper.cs
+++ b/src/SMAPI/Framework/ModHelpers/ContentHelper.cs
@@ -8,6 +8,7 @@ using System.Linq;
 using Microsoft.Xna.Framework.Content;
 using Microsoft.Xna.Framework.Graphics;
 using StardewModdingAPI.Framework.Exceptions;
+using StardewModdingAPI.Framework.Utilities;
 using StardewValley;
 using xTile;
 using xTile.Format;
@@ -238,7 +239,7 @@ namespace StardewModdingAPI.Framework.ModHelpers
                 string imageSource = tilesheet.ImageSource;
 
                 // validate tilesheet path
-                if (Path.IsPathRooted(imageSource) || imageSource.Split(SContentManager.PossiblePathSeparators).Contains(".."))
+                if (Path.IsPathRooted(imageSource) || PathUtilities.GetSegments(imageSource).Contains(".."))
                     throw new ContentLoadException($"The '{imageSource}' tilesheet couldn't be loaded. Tilesheet paths must be a relative path without directory climbing (../).");
 
                 // get seasonal name (if applicable)
diff --git a/src/SMAPI/Framework/SContentManager.cs b/src/SMAPI/Framework/SContentManager.cs
index 463fea0b..fa51bd53 100644
--- a/src/SMAPI/Framework/SContentManager.cs
+++ b/src/SMAPI/Framework/SContentManager.cs
@@ -35,9 +35,6 @@ namespace StardewModdingAPI.Framework
         /*********
         ** Properties
         *********/
-        /// <summary>The preferred directory separator chaeacter in an asset key.</summary>
-        private static readonly string PreferredPathSeparator = Path.DirectorySeparatorChar.ToString();
-
         /// <summary>Encapsulates monitoring and logging.</summary>
         private readonly IMonitor Monitor;
 
@@ -75,9 +72,6 @@ namespace StardewModdingAPI.Framework
         /// <summary>Interceptors which edit matching assets after they're loaded.</summary>
         internal IDictionary<IModMetadata, IList<IAssetEditor>> Editors { get; } = new Dictionary<IModMetadata, IList<IAssetEditor>>();
 
-        /// <summary>The possible directory separator characters in an asset key.</summary>
-        internal static readonly char[] PossiblePathSeparators = new[] { '/', '\\', Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar }.Distinct().ToArray();
-
         /// <summary>The absolute path to the <see cref="ContentManager.RootDirectory"/>.</summary>
         internal string FullRootDirectory => Path.Combine(Constants.ExecutionPath, this.RootDirectory);
 
@@ -100,7 +94,7 @@ namespace StardewModdingAPI.Framework
         {
             // init
             this.Monitor = monitor ?? throw new ArgumentNullException(nameof(monitor));
-            this.Cache = new ContentCache(this, reflection, SContentManager.PossiblePathSeparators, SContentManager.PreferredPathSeparator);
+            this.Cache = new ContentCache(this, reflection);
             this.GetKeyLocale = reflection.GetMethod(this, "languageCode");
             this.ModContentPrefix = this.GetAssetNameFromFilePath(Constants.ModPath);
 
@@ -399,15 +393,7 @@ namespace StardewModdingAPI.Framework
         /// <param name="targetPath">The target file path.</param>
         private string GetRelativePath(string targetPath)
         {
-            // convert to URIs
-            Uri from = new Uri(this.FullRootDirectory + "/");
-            Uri to = new Uri(targetPath + "/");
-            if (from.Scheme != to.Scheme)
-                throw new InvalidOperationException($"Can't get path for '{targetPath}' relative to '{this.FullRootDirectory}'.");
-
-            // get relative path
-            return Uri.UnescapeDataString(from.MakeRelativeUri(to).ToString())
-                .Replace(Path.DirectorySeparatorChar == '/' ? '\\' : '/', Path.DirectorySeparatorChar); // use correct separator for platform
+            return PathUtilities.GetRelativePath(this.FullRootDirectory, targetPath);
         }
 
         /// <summary>Get the locale codes (like <c>ja-JP</c>) used in asset keys.</summary>
diff --git a/src/SMAPI/Framework/Utilities/PathUtilities.cs b/src/SMAPI/Framework/Utilities/PathUtilities.cs
new file mode 100644
index 00000000..4fa521f1
--- /dev/null
+++ b/src/SMAPI/Framework/Utilities/PathUtilities.cs
@@ -0,0 +1,59 @@
+using System;
+using System.Diagnostics.Contracts;
+using System.IO;
+using System.Linq;
+
+namespace StardewModdingAPI.Framework.Utilities
+{
+    /// <summary>Provides utilities for normalising file paths.</summary>
+    internal static class PathUtilities
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The possible directory separator characters in a file path.</summary>
+        private static readonly char[] PossiblePathSeparators = new[] { '/', '\\', Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar }.Distinct().ToArray();
+
+        /// <summary>The preferred directory separator chaeacter in an asset key.</summary>
+        private static readonly string PreferredPathSeparator = Path.DirectorySeparatorChar.ToString();
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Get the segments from a path (e.g. <c>/usr/bin/boop</c> => <c>usr</c>, <c>bin</c>, and <c>boop</c>).</summary>
+        /// <param name="path">The path to split.</param>
+        public static string[] GetSegments(string path)
+        {
+            return path.Split(PathUtilities.PossiblePathSeparators, StringSplitOptions.RemoveEmptyEntries);
+        }
+
+        /// <summary>Normalise path separators in a file path.</summary>
+        /// <param name="path">The file path to normalise.</param>
+        [Pure]
+        public static string NormalisePathSeparators(string path)
+        {
+            string[] parts = PathUtilities.GetSegments(path);
+            string normalised = string.Join(PathUtilities.PreferredPathSeparator, parts);
+            if (path.StartsWith(PathUtilities.PreferredPathSeparator))
+                normalised = PathUtilities.PreferredPathSeparator + normalised; // keep root slash
+            return normalised;
+        }
+
+        /// <summary>Get a directory or file path relative to a given source path.</summary>
+        /// <param name="sourceDir">The source folder path.</param>
+        /// <param name="targetPath">The target folder or file path.</param>
+        [Pure]
+        public static string GetRelativePath(string sourceDir, string targetPath)
+        {
+            // convert to URIs
+            Uri from = new Uri(sourceDir.TrimEnd(PathUtilities.PossiblePathSeparators) + "/");
+            Uri to = new Uri(targetPath.TrimEnd(PathUtilities.PossiblePathSeparators) + "/");
+            if (from.Scheme != to.Scheme)
+                throw new InvalidOperationException($"Can't get path for '{targetPath}' relative to '{sourceDir}'.");
+
+            // get relative path
+            return PathUtilities.NormalisePathSeparators(Uri.UnescapeDataString(from.MakeRelativeUri(to).ToString()));
+        }
+    }
+}
diff --git a/src/SMAPI/StardewModdingAPI.csproj b/src/SMAPI/StardewModdingAPI.csproj
index 562da60d..14ed1531 100644
--- a/src/SMAPI/StardewModdingAPI.csproj
+++ b/src/SMAPI/StardewModdingAPI.csproj
@@ -125,6 +125,7 @@
     <Compile Include="Framework\Serialisation\CrossplatformConverters\ColorConverter.cs" />
     <Compile Include="Framework\Serialisation\CrossplatformConverters\PointConverter.cs" />
     <Compile Include="Framework\Utilities\ContextHash.cs" />
+    <Compile Include="Framework\Utilities\PathUtilities.cs" />
     <Compile Include="IContentPack.cs" />
     <Compile Include="IManifestContentPackFor.cs" />
     <Compile Include="IReflectedField.cs" />