diff --git a/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Bench/Inputs.fs b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Bench/Inputs.fs
index 2d29639..58cd579 100644
--- a/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Bench/Inputs.fs
+++ b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Bench/Inputs.fs
@@ -14,6 +14,6 @@ module Inputs =
             if isNull dir then
                 failwith "reached root of filesystem without finding inputs dir"
 
-        Array.init 14 (fun day -> Path.Combine (dir.FullName, "inputs", $"day%i{day + 1}.txt") |> File.ReadAllText)
+        Array.init 15 (fun day -> Path.Combine (dir.FullName, "inputs", $"day%i{day + 1}.txt") |> File.ReadAllText)
 
     let inline day (i : int) = days.[i - 1]
diff --git a/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Bench/Program.fs b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Bench/Program.fs
index 85029c0..8de9c54 100644
--- a/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Bench/Program.fs
+++ b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Bench/Program.fs
@@ -44,7 +44,7 @@ module Benchmarks =
         [<GlobalSetup>]
         member _.Setup () = Run.shouldWrite <- false
 
-        [<Params(11, 12, 13, 14)>]
+        [<Params(11, 12, 13, 14, 15)>]
         member val Day = 0 with get, set
 
         [<Params(false, true)>]
diff --git a/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Bench/Run.fs b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Bench/Run.fs
index 90c329c..8f7a676 100644
--- a/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Bench/Run.fs
+++ b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Bench/Run.fs
@@ -197,6 +197,18 @@ module Run =
             if shouldWrite then
                 Console.WriteLine output
 
+    let day15 (partTwo : bool) (input : string) =
+        if not partTwo then
+            let output = Day15.part1 input
+
+            if shouldWrite then
+                Console.WriteLine output
+        else
+            let output = Day15.part2 input
+
+            if shouldWrite then
+                Console.WriteLine output
+
     let allRuns =
         [|
             day1
@@ -213,4 +225,5 @@ module Run =
             day12
             day13
             day14
+            day15
         |]
diff --git a/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/AdventOfCode2023.FSharp.Lib.fsproj b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/AdventOfCode2023.FSharp.Lib.fsproj
index 1290625..8bdcbba 100644
--- a/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/AdventOfCode2023.FSharp.Lib.fsproj
+++ b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/AdventOfCode2023.FSharp.Lib.fsproj
@@ -25,6 +25,7 @@
     <Compile Include="Day12.fs" />
     <Compile Include="Day13.fs" />
     <Compile Include="Day14.fs" />
+    <Compile Include="Day15.fs" />
   </ItemGroup>
 
 </Project>
diff --git a/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/Day15.fs b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/Day15.fs
new file mode 100644
index 0000000..d7a9d7b
--- /dev/null
+++ b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp.Lib/Day15.fs
@@ -0,0 +1,11 @@
+namespace AdventOfCode2023
+
+open System
+
+[<RequireQualifiedAccess>]
+module Day15 =
+    let part1 (s : string) =
+        0
+
+    let part2 (s : string) =
+        0
diff --git a/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp/Program.fs b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp/Program.fs
index 8689c4b..9e7b12d 100644
--- a/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp/Program.fs
+++ b/AdventOfCode2023.FSharp/AdventOfCode2023.FSharp/Program.fs
@@ -284,6 +284,22 @@ module Program =
             Console.WriteLine (part2.ToString ())
             Console.Error.WriteLine ((1_000.0 * float sw.ElapsedTicks / float Stopwatch.Frequency).ToString () + "ms")
 
+        Console.WriteLine "=====Day 15====="
+
+        do
+            let input = Path.Combine (dir.FullName, "day15.txt") |> File.ReadAllText
+
+            sw.Restart ()
+            let part1 = Day15.part1 input
+            sw.Stop ()
+            Console.WriteLine (part1.ToString ())
+            Console.Error.WriteLine ((1_000.0 * float sw.ElapsedTicks / float Stopwatch.Frequency).ToString () + "ms")
+            sw.Restart ()
+            let part2 = Day15.part2 input
+            sw.Stop ()
+            Console.WriteLine (part2.ToString ())
+            Console.Error.WriteLine ((1_000.0 * float sw.ElapsedTicks / float Stopwatch.Frequency).ToString () + "ms")
+
         endToEnd.Stop ()
 
         Console.Error.WriteLine (
diff --git a/AdventOfCode2023.FSharp/Test/Test.fsproj b/AdventOfCode2023.FSharp/Test/Test.fsproj
index 75f79a1..2a6094c 100644
--- a/AdventOfCode2023.FSharp/Test/Test.fsproj
+++ b/AdventOfCode2023.FSharp/Test/Test.fsproj
@@ -23,6 +23,7 @@
     <Compile Include="TestDay12.fs" />
     <Compile Include="TestDay13.fs" />
     <Compile Include="TestDay14.fs" />
+    <Compile Include="TestDay15.fs" />
     <EmbeddedResource Include="samples\day1.txt"/>
     <EmbeddedResource Include="samples\day1part1.txt"/>
     <EmbeddedResource Include="samples\day2.txt"/>
@@ -40,6 +41,7 @@
     <EmbeddedResource Include="samples\day12.txt" />
     <EmbeddedResource Include="samples\day13.txt" />
     <EmbeddedResource Include="samples\day14.txt" />
+    <EmbeddedResource Include="samples\day15.txt" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/AdventOfCode2023.FSharp/Test/TestDay15.fs b/AdventOfCode2023.FSharp/Test/TestDay15.fs
new file mode 100644
index 0000000..0cfb73e
--- /dev/null
+++ b/AdventOfCode2023.FSharp/Test/TestDay15.fs
@@ -0,0 +1,48 @@
+namespace AdventOfCode2023.Test
+
+open System
+
+open AdventOfCode2023
+open NUnit.Framework
+open FsUnitTyped
+open System.IO
+
+[<TestFixture>]
+module TestDay15 =
+
+    [<Test>]
+    let sample = Assembly.getEmbeddedResource typeof<Dummy>.Assembly "day15.txt"
+
+    [<Test>]
+    let part1Sample () =
+        sample |> Day15.part1 |> shouldEqual -1
+
+    [<Test>]
+    let part2Sample () =
+        sample |> Day15.part2 |> shouldEqual -1
+
+    [<Test>]
+    let part1Actual () =
+        let s =
+            try
+                File.ReadAllText (Path.Combine (__SOURCE_DIRECTORY__, "../../inputs/day15.txt"))
+            with
+            | :? DirectoryNotFoundException
+            | :? FileNotFoundException ->
+                Assert.Inconclusive ()
+                failwith "unreachable"
+
+        Day15.part1 s |> shouldEqual -1
+
+    [<Test>]
+    let part2Actual () =
+        let s =
+            try
+                File.ReadAllText (Path.Combine (__SOURCE_DIRECTORY__, "../../inputs/day15.txt"))
+            with
+            | :? DirectoryNotFoundException
+            | :? FileNotFoundException ->
+                Assert.Inconclusive ()
+                failwith "unreachable"
+
+        Day15.part2 s |> shouldEqual -1
diff --git a/AdventOfCode2023.FSharp/Test/samples/day15.txt b/AdventOfCode2023.FSharp/Test/samples/day15.txt
new file mode 100644
index 0000000..e69de29