UPF stands for Ultraviolet Protection Factor and is similar to SPF ratings used in suncreams. Garments with a UPF of 50 only allow 1/50th of the UV radiation falling on the garment to pass through it. The highest UPF rating a garment can be assigned is 50+, a piece in this range is determined as providing “excellent” protection from UV radiation. All Modibodi Swimsuits are rated UPF 50+. This is not a replacement for sunscreen and additional sun protection should always be used.