UPF or Ultraviolet Protection Factor, measures the sun protection provided by clothing, while SPF, or Sun Protection Factor, gauges the effectiveness of sunscreen. While SPF primarily shields against UVB rays, causing sunburn, UPF evaluates protection against both UVA and UVB which are important for preventing long-term skin damage. Think of SPF for your skin and UPF for your wardrobe. Together, they're your dynamic duo in the battle against sun damage.