diff --git a/lib/std/crypto/pbkdf2.zig b/lib/std/crypto/pbkdf2.zig
index 52f9da5cd7..575fb83006 100644
--- a/lib/std/crypto/pbkdf2.zig
+++ b/lib/std/crypto/pbkdf2.zig
@@ -79,7 +79,7 @@ pub fn pbkdf2(dk: []u8, password: []const u8, salt: []const u8, rounds: u32, com
     //      block
     //
 
-    const blocks_count = (dk_len + h_len - 1) / h_len;
+    const blocks_count = @intCast(u32, std.math.divCeil(usize, dk_len, h_len) catch unreachable);
     var r = dk_len % h_len;
     if (r == 0) {
         r = h_len;