diff --git a/frontend/src/stores/config.ts b/frontend/src/stores/config.ts
index 4435978..13132d2 100644
--- a/frontend/src/stores/config.ts
+++ b/frontend/src/stores/config.ts
@@ -46,6 +46,9 @@ export interface PublicConfig {
   // Whether this server can email a reset link, so sign-in offers "Forgot password?"
   // (#5266). Absent on an older server and on the offline desktop: no.
   password_reset_by_email?: boolean;
+  // The shortest password an account may have (the server's MIN_PASSWORD_LEN).
+  // Absent on an older server and on the offline desktop, which has no accounts.
+  min_password_length?: number;
   // Every client this server holds, keyed by platform id. Absent on a server that
   // holds none, and absent on the desktop's own offline config — the Tauri build
   // answers `config_get` locally and has no clients to hand out.
@@ -66,6 +69,8 @@ export const useConfigStore = defineStore("config", () => {
   // that never had the field, both correctly offer no downloads.
   const clients = ref<Record<string, ClientRelease>>({});
   const passwordResetByEmail = ref(false);
+  // The server's own number; 8 only until /api/config answers, or if it never does.
+  const minPasswordLength = ref(8);
   const loaded = ref(false);
 
   async function load(): Promise<void> {
@@ -79,6 +84,7 @@ export const useConfigStore = defineStore("config", () => {
       trashRetentionDays.value = cfg.trash_retention_days ?? 30;
       clients.value = cfg.clients ?? {};
       passwordResetByEmail.value = cfg.password_reset_by_email ?? false;
+      minPasswordLength.value = cfg.min_password_length ?? 8;
     } catch {
       // Keep defaults if the config endpoint is unreachable.
     } finally {
@@ -99,6 +105,7 @@ export const useConfigStore = defineStore("config", () => {
     trashRetentionDays,
     clients,
     passwordResetByEmail,
+    minPasswordLength,
     loaded,
     load,
     reload,
diff --git a/frontend/src/views/AccountView.vue b/frontend/src/views/AccountView.vue
index 3fb4160..dd6fbdf 100644
--- a/frontend/src/views/AccountView.vue
+++ b/frontend/src/views/AccountView.vue
@@ -264,7 +264,7 @@ onMounted(() => {
         type="password"
         label="New password"
         autocomplete="new-password"
-        placeholder="At least 8 characters"
+        :placeholder="`At least ${config.minPasswordLength} characters`"
         :error="passwordError"
         required
       />
diff --git a/frontend/src/views/RegisterView.vue b/frontend/src/views/RegisterView.vue
index d583624..190aba9 100644
--- a/frontend/src/views/RegisterView.vue
+++ b/frontend/src/views/RegisterView.vue
@@ -24,8 +24,8 @@ const loading = ref(false);
 
 async function submit() {
   error.value = "";
-  if (password.value.length < 8) {
-    error.value = "Password must be at least 8 characters.";
+  if (password.value.length < config.minPasswordLength) {
+    error.value = `Password must be at least ${config.minPasswordLength} characters.`;
     return;
   }
   loading.value = true;
@@ -80,7 +80,7 @@ async function submit() {
           label="Password"
           type="password"
           autocomplete="new-password"
-          placeholder="At least 8 characters"
+          :placeholder="`At least ${config.minPasswordLength} characters`"
           required
         />
         <p
diff --git a/frontend/src/views/ResetPasswordView.vue b/frontend/src/views/ResetPasswordView.vue
index 1fe064e..0b06020 100644
--- a/frontend/src/views/ResetPasswordView.vue
+++ b/frontend/src/views/ResetPasswordView.vue
@@ -25,8 +25,8 @@ const loading = ref(false);
 
 async function submit() {
   error.value = "";
-  if (password.value.length < 8) {
-    error.value = "Password must be at least 8 characters.";
+  if (password.value.length < config.minPasswordLength) {
+    error.value = `Password must be at least ${config.minPasswordLength} characters.`;
     return;
   }
   if (password.value !== confirm.value) {
@@ -77,7 +77,7 @@ async function submit() {
           label="New password"
           type="password"
           autocomplete="new-password"
-          placeholder="At least 8 characters"
+          :placeholder="`At least ${config.minPasswordLength} characters`"
           required
         />
         <BaseInput
diff --git a/src/inkwell/auth.py b/src/inkwell/auth.py
index c17d214..c86b277 100644
--- a/src/inkwell/auth.py
+++ b/src/inkwell/auth.py
@@ -26,7 +26,7 @@ from .ratelimit import (
     sign_in_by_address,
 )
 from .security import dummy_verify, generate_token, hash_password, hash_token, verify_password
-from .settings import get_setting, mail_configured, set_settings
+from .settings import MIN_PASSWORD_LEN, get_setting, mail_configured, set_settings
 from .storage import storage_limit, storage_used
 
 bp = Blueprint("auth", __name__, url_prefix="/api/auth")
@@ -46,7 +46,6 @@ SESSION_KEY = "user_id"
 # signed cookies in other people's browsers. A cookie from before epochs existed has
 # no key and reads as 0, the epoch every account started at.
 EPOCH_KEY = "epoch"
-MIN_PASSWORD_LEN = 8
 
 # The first account can only be created this long after the server starts (family
 # idea #5105, practice 8). Without it, a fresh server on a public address belongs to
diff --git a/src/inkwell/settings.py b/src/inkwell/settings.py
index ccee00a..3d76510 100644
--- a/src/inkwell/settings.py
+++ b/src/inkwell/settings.py
@@ -16,6 +16,10 @@ SettingType = Literal["string", "bool", "int"]
 # attachment an admin may allow is a megabyte under it.
 MAX_BODY_MB = 64
 
+# The shortest password an account may have. Enforced by auth.py, and served in the
+# public config so the web's forms say the same number before a round-trip does.
+MIN_PASSWORD_LEN = 8
+
 
 @dataclass(frozen=True)
 class SettingDef:
@@ -320,6 +324,7 @@ async def get_public_config(db) -> dict:
         "trash_retention_days": await get_setting(db, "trash_retention_days"),
         # Whether the sign-in screen offers "Forgot password?" (#5266).
         "password_reset_by_email": await mail_configured(db),
+        "min_password_length": MIN_PASSWORD_LEN,
     }