diff --git a/.env.example b/.env.example
index 4bb4d671..1a1c51da 100644
--- a/.env.example
+++ b/.env.example
@@ -17,6 +17,11 @@ AUTH_SECRET=
 APP_KEY=
 CONVERT_PASSWORDS=false
 
+# Password hashing for NEW/upgraded passwords: "bcrypt" (default; 60-char $2y$,
+# fits a varchar(64) users.password) or "argon2id" (~97 chars, needs a wider
+# column). Existing accounts in either format still verify on login.
+PASSWORD_HASH=bcrypt
+
 # RCON link to the Arcturus emulator
 RCON_HOST=127.0.0.1
 RCON_PORT=3001
diff --git a/src/lib/auth/password.test.ts b/src/lib/auth/password.test.ts
index 62f8a502..24c36e15 100644
--- a/src/lib/auth/password.test.ts
+++ b/src/lib/auth/password.test.ts
@@ -15,12 +15,36 @@ describe("md5Hex", () => {
   });
 });
 
-describe("argon2id", () => {
+describe("hashPassword (default driver: bcrypt)", () => {
+  it("emits a PHP-style $2y$ bcrypt hash that fits varchar(64) and round-trips", async () => {
+    const prev = process.env.PASSWORD_HASH;
+    delete process.env.PASSWORD_HASH; // exercise the default
+    try {
+      const h = await hashPassword("s3cret!");
+      expect(h).toMatch(/^\$2y\$/);
+      expect(h.length).toBeLessThanOrEqual(60); // fits varchar(64)
+      expect(await verifyPassword("s3cret!", h)).toBe(true);
+      expect(await verifyPassword("wrong", h)).toBe(false);
+    } finally {
+      if (prev === undefined) delete process.env.PASSWORD_HASH;
+      else process.env.PASSWORD_HASH = prev;
+    }
+  });
+});
+
+describe("hashPassword (PASSWORD_HASH=argon2id)", () => {
   it("hashes with the AtomCMS params (m=65536,t=4,p=1) and round-trips", async () => {
-    const h = await hashPassword("s3cret!");
-    expect(h).toMatch(/^\$argon2id\$v=19\$m=65536,t=4,p=1\$/);
-    expect(await verifyPassword("s3cret!", h)).toBe(true);
-    expect(await verifyPassword("wrong", h)).toBe(false);
+    const prev = process.env.PASSWORD_HASH;
+    process.env.PASSWORD_HASH = "argon2id";
+    try {
+      const h = await hashPassword("s3cret!");
+      expect(h).toMatch(/^\$argon2id\$v=19\$m=65536,t=4,p=1\$/);
+      expect(await verifyPassword("s3cret!", h)).toBe(true);
+      expect(await verifyPassword("wrong", h)).toBe(false);
+    } finally {
+      if (prev === undefined) delete process.env.PASSWORD_HASH;
+      else process.env.PASSWORD_HASH = prev;
+    }
   });
 });
 
@@ -44,11 +68,13 @@ describe("isMd5Of", () => {
 });
 
 describe("checkLogin", () => {
-  it("upgrades a legacy md5 hash to argon2id when conversion is enabled", async () => {
+  it("upgrades a legacy md5 hash to the configured hash when conversion is enabled", async () => {
     const stored = md5Hex("oldpass");
     const res = await checkLogin("oldpass", stored, { convertPasswords: true });
     expect(res.valid).toBe(true);
-    expect(res.upgradedHash).toMatch(/^\$argon2id\$/);
+    // Default driver is bcrypt — the upgraded hash must fit varchar(64).
+    expect(res.upgradedHash).toMatch(/^\$2y\$/);
+    expect((res.upgradedHash as string).length).toBeLessThanOrEqual(60);
     // The upgraded hash verifies the same password.
     expect(await verifyPassword("oldpass", res.upgradedHash as string)).toBe(true);
   });
@@ -60,7 +86,7 @@ describe("checkLogin", () => {
     expect(res.upgradedHash).toBeUndefined();
   });
 
-  it("validates an existing argon2id hash with no upgrade", async () => {
+  it("validates an existing modern hash with no upgrade", async () => {
     const stored = await hashPassword("modern");
     const res = await checkLogin("modern", stored, { convertPasswords: true });
     expect(res.valid).toBe(true);
diff --git a/src/lib/auth/password.ts b/src/lib/auth/password.ts
index 4176f324..3464cc7f 100644
--- a/src/lib/auth/password.ts
+++ b/src/lib/auth/password.ts
@@ -1,30 +1,51 @@
 import { createHash, randomBytes } from "node:crypto";
-import { compare as bcryptCompare } from "bcryptjs";
+import { compare as bcryptCompare, hash as bcryptHash } from "bcryptjs";
 import { argon2id, argon2Verify } from "hash-wasm";
 
-// AtomCMS hashing (config/hashing.php): default driver argon2id with
-// memory=65536 KiB, time=4, threads=1; bcrypt rounds=12 as the legacy fallback.
-// The game emulator validates the SAME users.password hash, so these must match.
+// AtomCMS hashing (config/hashing.php): argon2id with memory=65536 KiB, time=4,
+// threads=1; bcrypt rounds=12 as the legacy fallback. The game emulator
+// validates the SAME users.password hash, so these must match.
 const ARGON2_PARAMS = {
   parallelism: 1,
   iterations: 4,
   memorySize: 65536, // KiB
   hashLength: 32,
 } as const;
+const BCRYPT_ROUNDS = 12;
+
+// Which algorithm hashPassword() emits for NEW/upgraded passwords.
+//   - "bcrypt"  (DEFAULT): 60-char $2y$ hash. Fits a varchar(64) users.password
+//     (the common emulator/AtomCMS column width) and matches existing accounts.
+//   - "argon2id": ~97-char PHC hash. ONLY usable if users.password is widened
+//     (e.g. varchar(255)). Opt in with PASSWORD_HASH=argon2id.
+// verifyPassword() always accepts BOTH, so logins keep working either way.
+function hashDriver(): "bcrypt" | "argon2id" {
+  return process.env.PASSWORD_HASH?.toLowerCase() === "argon2id" ? "argon2id" : "bcrypt";
+}
 
 /** Lowercase hex md5 of a UTF-8 string (matches PHP md5()). */
 export function md5Hex(input: string): string {
   return createHash("md5").update(input, "utf8").digest("hex");
 }
 
-/** Produce an argon2id hash in PHC format identical to PHP's PASSWORD_ARGON2ID. */
+/**
+ * Hash a new password with the configured driver. Defaults to bcrypt ($2y$,
+ * rounds=12) so the result fits a varchar(64) column; set PASSWORD_HASH=argon2id
+ * for argon2id (requires a wider column). Both are verifiable by verifyPassword.
+ */
 export async function hashPassword(password: string): Promise<string> {
-  return argon2id({
-    password,
-    salt: randomBytes(16),
-    outputType: "encoded",
-    ...ARGON2_PARAMS,
-  });
+  if (hashDriver() === "argon2id") {
+    return argon2id({
+      password,
+      salt: randomBytes(16),
+      outputType: "encoded",
+      ...ARGON2_PARAMS,
+    });
+  }
+  // bcryptjs emits $2a$/$2b$; normalise to the PHP-canonical $2y$ the emulator
+  // and existing AtomCMS rows use.
+  const h = await bcryptHash(password, BCRYPT_ROUNDS);
+  return h.replace(/^\$2[ab]\$/, "$2y$");
 }
 
 /** True when `stored` is exactly the md5 of `password` (legacy AtomCMS accounts). */