If you're planning delivery, installation, or just figuring out how many people you need to lift one, the short answer is that a double-seater park bench typically weighs about 1.5 to 2 times as much as a single-seater made from the same material and style. It's rarely exactly double because the frame, armrests, and hardware don't all scale at the same rate.
For a typical wooden park bench with metal legs, a single-seat version usually lands around 55–90 pounds, while a double-seater often runs 100–150 pounds. The wood species matters too: teak and oak are denser than pine or acacia, so they can push those numbers higher. If the bench has a backrest, add another 10–25 pounds compared to a backless design.
Metal benches vary more. A lightweight aluminum single can be as little as 40–60 pounds, while a double might be 70–110 pounds. On the heavier end, steel or cast iron benches are much more massive. A single cast iron bench can easily weigh 120–180 pounds, and a double-seater can reach 200–350 pounds or more, especially with ornate frames and thick slats.
Recycled plastic benches are deceptively heavy. A single often weighs 80–130 pounds, while a double-seater commonly falls between 150–250 pounds. They feel manageable because plastic doesn't look dense, but the material is solid and heavy.
Concrete and stone benches are in their own category. A single concrete bench can weigh 400–800 pounds, and a double-seater can be 600–1,200 pounds or more. These are usually placed with equipment and not moved by hand.
So if you're comparing the same material and design, expect the double-seater to add roughly 50–100% more weight rather than exactly doubling it. Always check the manufacturer's spec sheet before you plan a move, because hardware, thickness, and frame style can create big differences even between benches that look similar.