DownClock

Ever wondered exactly how long a 4K video will take to upload, or whether your new ISP plan is actually faster? DownClock gives you an instant, accurate answer. Enter a file size (KB to TB, binary or SI), pick your connection speed from common presets or type your own, and watch the result roll in — days, hours, minutes, seconds. Built for developers, IT admins, content creators, and anyone comparing ISP plans. No ads. No accounts. No nonsense. FEATURES - File sizes from KB to TB — binary (KiB/GiB) and SI units - Speed presets: 1 Mbps to 10 Gbps - Compare two ISP providers side by side - Calculation history - Protocol overhead slider (TCP/IP + HTTP) - ISP efficiency slider (advertised vs. actual speed) - Animated rolling-digit result display - Light, dark, or system appearance - iPhone and iPad — portrait optimized - Zero network requests. Completely private.