Bandwidth Calculator - Calculatrice en ligne gratuite

A bandwidth calculator answers two practical questions every Indian internet user faces: 'how long will this download take?' and 'will my monthly data plan be enough?'. With JioFiber, Airtel Xstream, ACT, BSNL, Excitel and hundreds of regional ISPs offering plans from 50 Mbps to 1 Gbps and mobile plans with FUP (Fair Usage Policy) limits of 1.5 GB/day to 3 GB/day, knowing how speed and data interact is essential. The most common confusion is bits vs bytes - internet speeds are in Megabits per second (Mbps) but file sizes are in Megabytes (MB), and 1 byte = 8 bits, so a 100 Mbps connection downloads files at 12.5 MB/s peak.

This calculator handles both directions: enter file size and speed to get download time, or enter speed and usage hours to estimate monthly GB. Useful for: estimating Netflix/Prime Video streaming time on a flight Wi-Fi, calculating how long a large game download will take, sizing broadband plans for a family of streamers, checking if your mobile data plan will last through the month, and planning large business file transfers. Real-world throughput is typically 80-90% of advertised speed due to TCP/IP overhead, server limits and Wi-Fi loss, so add 10-20% buffer to download time estimates.

Download time formula: convert file size to bits (size_in_bytes × 8), divide by speed in bits-per-second. Example: 5 GB file at 100 Mbps. 5 GB = 5,000 MB = 5,000,000,000 bytes × 8 = 40,000,000,000 bits. At 100,000,000 bps: 400 seconds = 6 minutes 40 seconds. In reality, add 10-20% for overhead - call it 8 minutes.

Unit conversions are the trickiest part. Decimal SI: 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes, 1 GB = 1,000,000,000 bytes (used by ISPs and storage manufacturers). Binary: 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes (used by operating systems for memory). This calculator uses decimal SI for speed and file size - matches what most users see on bills and download progress bars.

Monthly usage: continuous streaming at speed S Mbps for H hours per day, over 30 days. Total bits = S × 1,000,000 × H × 3600 × 30. Convert to GB: divide by 8 × 1,000,000,000. So 25 Mbps × 4 hours/day × 30 days = 1,350 GB/month. Most streaming services compress aggressively - Netflix HD uses ~3 GB/hr, 4K ~7 GB/hr; YouTube similar. Mobile FUP plans of 1.5 GB/day cap heavy streaming around 30-45 minutes HD per day.