A stair ladder stabilizer, designed to enhance safety and convenience when using extension ladders on stairs. It features an adjustable platform that accommodates different step widths, allowing for a secure fit on various staircases. The seamless height adjustment and quick-adjust structure enable easy and rapid setup to match the height of staircase steps. Constructed from durable steel with a powder coating, it resists corrosion and wear, ensuring long-lasting performance. Equipped with anti-skid rubber pads, it provides stability on both indoor and outdoor two-foot stair ladders, compatible with extension, straight, and telescopic ladders. The foldable design simplifies storage, saving space, while the tool can be set up in minutes without installation, moving easily between stairs for versatile use. Its base width of 21"x5.65" and height adjustment range of 9.25"-15.5" fit standard staircase dimensions, making it a practical accessory for ladder use on stairs.