diff --git a/app/src/main/java/com/x8bit/bitwarden/data/auth/repository/util/UserStateJsonExtensions.kt b/app/src/main/java/com/x8bit/bitwarden/data/auth/repository/util/UserStateJsonExtensions.kt
index 29e6521b7e..5a921fa487 100644
--- a/app/src/main/java/com/x8bit/bitwarden/data/auth/repository/util/UserStateJsonExtensions.kt
+++ b/app/src/main/java/com/x8bit/bitwarden/data/auth/repository/util/UserStateJsonExtensions.kt
@@ -4,6 +4,7 @@ import com.x8bit.bitwarden.data.auth.datasource.disk.model.UserStateJson
 import com.x8bit.bitwarden.data.auth.repository.model.UserState
 import com.x8bit.bitwarden.data.vault.datasource.network.model.SyncResponseJson
 import com.x8bit.bitwarden.data.vault.repository.model.VaultState
+import com.x8bit.bitwarden.ui.platform.base.util.toHexColorRepresentation
 
 /**
  * Updates the given [UserStateJson] with the data from the [syncResponse] to return a new
@@ -51,8 +52,8 @@ fun UserStateJson.toUserState(
                     userId = accountJson.profile.userId,
                     name = accountJson.profile.name,
                     email = accountJson.profile.email,
-                    // TODO Calculate default color (BIT-1191)
-                    avatarColorHex = accountJson.profile.avatarColorHex ?: "#00aaaa",
+                    avatarColorHex = accountJson.profile.avatarColorHex
+                        ?: accountJson.profile.userId.toHexColorRepresentation(),
                     isPremium = accountJson.profile.hasPremium == true,
                     isVaultUnlocked = userId in vaultState.unlockedVaultUserIds,
                 )
diff --git a/app/src/main/java/com/x8bit/bitwarden/ui/platform/base/util/StringExtensions.kt b/app/src/main/java/com/x8bit/bitwarden/ui/platform/base/util/StringExtensions.kt
index 532ea019e9..201dac9b7d 100644
--- a/app/src/main/java/com/x8bit/bitwarden/ui/platform/base/util/StringExtensions.kt
+++ b/app/src/main/java/com/x8bit/bitwarden/ui/platform/base/util/StringExtensions.kt
@@ -54,3 +54,28 @@ fun String.hexToColor(): Color = if (startsWith("#")) {
 } else {
     Color("#$this".toColorInt())
 }
+
+/**
+ * Creates a new [String] that represents a unique color in the hex representation (`"#AARRGGBB"`).
+ * This can be applied to any [String] in order to provide some deterministic color value based on
+ * arbitrary [String] properties.
+ */
+@OptIn(ExperimentalStdlibApi::class)
+@Suppress("MagicNumber")
+fun String.toHexColorRepresentation(): String {
+    // Produces a string with exactly two hexadecimal digits.
+    // Ex:
+    // 0 -> "00"
+    // 10 -> "0a"
+    // 1000 -> "e8"
+    fun Int.toTwoDigitHexString(): String =
+        this.toHexString().takeLast(2)
+
+    // Calculates separate red, blue, and green values from different positions in the hash and then
+    // combines then into a single color.
+    val hash = this.hashCode()
+    val red = (hash and 0x0000FF).toTwoDigitHexString()
+    val green = ((hash and 0x00FF00) shr 8).toTwoDigitHexString()
+    val blue = ((hash and 0xFF0000) shr 16).toTwoDigitHexString()
+    return "#ff$red$green$blue"
+}
diff --git a/app/src/test/java/com/x8bit/bitwarden/data/auth/repository/util/UserStateJsonExtensionsTest.kt b/app/src/test/java/com/x8bit/bitwarden/data/auth/repository/util/UserStateJsonExtensionsTest.kt
index 170cf3ec4f..23b39a5fa4 100644
--- a/app/src/test/java/com/x8bit/bitwarden/data/auth/repository/util/UserStateJsonExtensionsTest.kt
+++ b/app/src/test/java/com/x8bit/bitwarden/data/auth/repository/util/UserStateJsonExtensionsTest.kt
@@ -135,7 +135,8 @@ class UserStateJsonExtensionsTest {
                         userId = "activeUserId",
                         name = "activeName",
                         email = "activeEmail",
-                        avatarColorHex = "activeAvatarColorHex",
+                        // This value is calculated from the userId
+                        avatarColorHex = "#ffecbc49",
                         isPremium = true,
                         isVaultUnlocked = false,
                     ),
@@ -149,7 +150,7 @@ class UserStateJsonExtensionsTest {
                             every { userId } returns "activeUserId"
                             every { name } returns "activeName"
                             every { email } returns "activeEmail"
-                            every { avatarColorHex } returns "activeAvatarColorHex"
+                            every { avatarColorHex } returns null
                             every { hasPremium } returns true
                         },
                         tokens = mockk(),
diff --git a/app/src/test/java/com/x8bit/bitwarden/ui/platform/base/util/StringExtensionsTest.kt b/app/src/test/java/com/x8bit/bitwarden/ui/platform/base/util/StringExtensionsTest.kt
index 9777cffa4f..1dc2984371 100644
--- a/app/src/test/java/com/x8bit/bitwarden/ui/platform/base/util/StringExtensionsTest.kt
+++ b/app/src/test/java/com/x8bit/bitwarden/ui/platform/base/util/StringExtensionsTest.kt
@@ -1,5 +1,6 @@
 package com.x8bit.bitwarden.ui.platform.base.util
 
+import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Assertions.assertFalse
 import org.junit.jupiter.api.Assertions.assertTrue
 import org.junit.jupiter.api.Test
@@ -67,4 +68,22 @@ class StringExtensionsTest {
                 assertFalse(badUri.isValidUri())
             }
     }
+
+    @Test
+    fun `toHexColorRepresentation should return valid hex color values`() {
+        mapOf(
+            "First" to "#ff90e20b",
+            "Second" to "#ff943060",
+            "Multiple words" to "#ffb9d46a",
+            "1234567890-=!@#$%^&*()_+[]\\;',./{}|:\"<>?" to "#ff171178",
+            "" to "#ff000000",
+            " " to "#ff200000",
+        )
+            .forEach { (input, colorHexOutput) ->
+                assertEquals(
+                    colorHexOutput,
+                    input.toHexColorRepresentation(),
+                )
+            }
+    }
 }