How long to download 5 GB at 25 Mbps

Five gigabytes at 25 Mbps is 1,600 seconds, or 26 minutes 40 seconds

40,000 megabits divided by 25

Convert the size into bits before touching the clock, because that step is where most estimates go wrong. A gigabyte is 1,000 megabytes and a byte is 8 bits, so 5 GB is 5,000 MB and 5,000 x 8 = 40,000 megabits. Divide by the line speed: 40,000 / 25 = 1,600 seconds, which is 26 minutes 40 seconds.

Run it the other way and the same answer appears. Twenty five megabits per second is 25 / 8 = 3.125 megabytes per second, and 5,000 MB / 3.125 = 1,600 seconds. In minutes that is 26.67, in megabytes per minute it is 3.125 x 60 = 187.5 MB per minute, and 5,000 / 187.5 = 26.67 minutes again.

Break the clock apart and it reads better on a screen: 1,600 seconds is 26 full minutes plus 40 seconds. Nothing rounds in that split, so a download manager that shows 26:40 is showing the honest arithmetic rather than an estimate.

The table scales in a straight line while the speed holds, so 60 GB is exactly twelve times the wait of 5 GB. That linearity is the useful part: once you know one row, every other row is a multiplication you can do in your head.

The bar reads 3.125 MB per second, and the line is a quarter of the 2024 benchmark

Where 25 Mbps sits, and what it feels like

Twenty five megabits per second is a modest line in 2026. The FCC raised its fixed broadband benchmark to 100 Mbps down and 20 Mbps up in the Section 706 report adopted on 14 March 2024, four times the 25/3 standard it had used since 2015. A 25 Mbps plan is therefore 25 percent of the download floor and 125 percent of the upload floor.

That history explains why the number still shows up on bills. It was the headline speed of the benchmark for nine years, and entry cable tiers, DSL lines, fixed wireless plans and mobile hotspots still land near it. The FCC announcement of the 2024 benchmark is the reference for the current floor, and the old 25/3 number is why so many people remember 25 as fast.

At 3.125 MB per second, a 5 MB photo lands in 1.6 seconds, a 40 MB music album in 12.8 seconds, and a 700 MB television episode in 3 minutes 44 seconds. Web pages feel normal. The line only becomes visible when a file is measured in gigabytes, which is why a 5 GB download is the point where people start asking about the clock.

Plug in a speed test result rather than the advertised number. A 25 Mbps plan that measures 21 Mbps gives 40,000 / 21 = 1,904.8 seconds, or 31 minutes 45 seconds, which is 19 percent longer than the sticker figure.

Overhead adds 96 seconds: 1,696 seconds, or 28 minutes 16 seconds

Headers, acknowledgements and retransmits

The 1,600 second figure treats every bit on the wire as file data, and no network works that way. Each packet carries a header, the receiver acknowledges what arrived, and anything lost is sent again. On a full size transfer those costs run from 2 to 6 percent of the total, plus a second or two of slow start at the front.

Worked example at 6 percent: 1,600 x 1.06 = 1,696 seconds, which is 28 minutes 16 seconds. At 2 percent the job is 1,632 seconds, or 27 minutes 12 seconds. At 12 percent, which is a weak Wi-Fi signal with retries, it reaches 1,792 seconds, or 29 minutes 52 seconds.

The spread from 1,600 to 1,792 seconds is 192 seconds, just over three minutes. On a 5 GB file that is a coffee break. On a 60 GB game the same 12 percent adds 2,304 seconds, or 38 minutes 24 seconds, which is why a console shows a range instead of a single finish time.

Small files feel the fixed costs more than the percentage suggests. Slow start can eat half of a 20 MB transfer, so 5 GB is roughly the smallest size where the clean arithmetic lands within a minute of a stopwatch.

Read as 5 GiB, the same file takes 1,717.9869184 seconds

The binary reading is 7.37 percent longer

Windows reports file size in gibibytes, where 1 GiB is 1,024 MiB, while line speed is sold in decimal bits. A file that Windows calls 5.00 GB is usually 5 GiB, which is bigger than the 5 GB used above. Run the chain: 5 x 1,073,741,824 = 5,368,709,120 bytes, which is 42,949,672,960 bits.

Divide by 25,000,000 bits per second: 42,949,672,960 / 25,000,000 = 1,717.9869184 seconds, or 28 minutes 38 seconds. The gap against 1,600 seconds is 117.99 seconds, and as a share it is 7.37 percent, which is 1.024 cubed. The NIST page on binary prefixes explains why both readings exist and why the difference is not an error.

Add 6 percent overhead to the binary figure and the job reaches 1,821.07 seconds, or 30 minutes 21 seconds. That is the widest honest estimate on this page, and it is still under 31 minutes, so a half hour is a fair thing to tell someone waiting for the file.

The same mismatch makes a 2 TB drive show up as 1.81 TB in File Explorer. Drives are sold in decimal terabytes and the operating system counts binary ones. Nothing is missing from the drive and nothing is missing from the download, but a page that quotes one reading next to a progress bar that shows the other will always look 7 percent wrong.

A 4K stream leaves 10 Mbps and doubles the wait

Netflix bitrates and the evening block

A 25 Mbps line has room for one thing at a time, and a household rarely does one thing at a time. Netflix recommends 3 Mbps for 720p, 5 Mbps for 1080p and 15 Mbps for 4K, per its internet speed recommendations page. Take the 4K figure and the download has 25 - 15 = 10 Mbps left, which doubles the wait to 4,000 seconds, or 1 hour 6 minutes 40 seconds.

The lighter streams cost less. A 1080p title at 5 Mbps leaves 20 Mbps, so the job stretches to 2,000 seconds, or 33 minutes 20 seconds. A 720p title at 3 Mbps leaves 22 Mbps, which gives 1,818.2 seconds, or 30 minutes 18 seconds. Only the 4K case turns a half hour job into an hour long one.

Two screens are worse than one. A 1080p stream in the living room and a 720p stream in a bedroom use 8 Mbps between them, leaving 17 Mbps, which puts the download at 2,352.9 seconds, or 39 minutes 13 seconds. Add a video call at 3 Mbps and 14 Mbps remain, for 2,857.1 seconds, or 47 minutes 37 seconds.

Evening congestion is the other half of this. A line that tests at 25 Mbps at two in the afternoon can measure 14 Mbps between eight and ten at night, when the block is streaming and the neighborhood is online. That does not change the arithmetic, it changes the number you put into it: 40,000 / 14 = 2,857.1 seconds, the same 47 minutes 37 seconds as the video call case.

A 1.2 TB cap holds 240 copies, or 226 once overhead is counted

Caps, the month at full speed and a phone hotspot

A 1.2 TB cap is 1,200 GB, so 1,200 / 5 = 240 downloads of this file before the cap is gone. Count the traffic on the wire instead of the bytes in the file and the number drops: 5 GB becomes 5.3 GB with 6 percent overhead, and 1,200 / 5.3 = 226.42 copies. A 500 GB cap holds 100 copies and a 250 GB cap holds 50 at the clean figure.

Move the whole cap over a 25 Mbps line and the meter runs 1,200 GB x 8 = 9,600 Gb, which is 9,600,000 megabits, or 384,000 seconds. That is 106.67 hours, or 4.44 days of flat out transfer. A 1.2 TB cap is therefore not a limit a 25 Mbps line reaches by accident, and a household that hits it is streaming far more than it downloads.

Caps matter more on a hotspot. A phone plan that allows 15 GB of high speed data holds three copies of this file, and 5 GB at 25 Mbps on a phone uses 1 hour 6 minutes 40 seconds of battery and a third of that allowance. After the high speed allowance runs out the same file can take hours.

Storage is faster than the line by a wide margin, which is worth knowing before buying a drive to fix a slow download. A USB 2.0 drive writing 35 MB per second copies 5,000 MB in 142.9 seconds, or 2 minutes 23 seconds, and an SSD does it in well under a minute. The disk is never the reason a 5 GB download takes half an hour.

Games, updates and a 700 MB episode at 25 Mbps

The jobs that fill a queue

The file in the title is a film sized download, and the jobs people queue are larger. A 60 GB game is 480,000 megabits, which is 19,200 seconds, or 5 hours 20 minutes at 25 Mbps. A 20 GB console update is 6,400 seconds, or 1 hour 46 minutes 40 seconds. A 700 MB episode is 224 seconds, or 3 minutes 44 seconds.

The shape of those numbers decides when to start. A half hour film fits in a lunch break, a 20 GB update fits in an afternoon, and a 60 GB game needs an overnight window or a faster line. Doubling the line to 50 Mbps halves every row, which turns the game into 2 hours 40 minutes and the update into 53 minutes 20 seconds.

Console stores add their own overhead on top of the network. They unpack and install while the download runs, and on a slow line the unpacking finishes first, so the bar sits at 100 percent while the drive works. That last minute is the console, not the connection.

Resume matters at this scale. A download that drops at hour four of a five hour game costs an hour if the client supports range requests and starts over if it does not. Any browser or store client from the last decade resumes, and the older download managers that split a file into segments can use the whole line on a single transfer.

Planning the window: why 26 minutes becomes 40 in real life

Measured speed, Wi-Fi and the start time

The arithmetic says 26 minutes 40 seconds, and the wall clock usually says more. Three things add up: overhead of 4 to 6 percent, a line that delivers less than it advertises, and other traffic in the house. A 25 Mbps plan that measures 20 Mbps with 6 percent overhead lands at 40,000 / 20 x 1.06 = 2,120 seconds, or 35 minutes 20 seconds.

Wi-Fi is the largest single variable on a line this slow. A laptop two rooms from the router on a crowded 2.4 GHz channel often sees 12 to 16 Mbps of goodput, which puts the file at 40,000 / 14 x 1.06 = 3,028.6 seconds, or 50 minutes 29 seconds. An Ethernet cable removes that loss for the price of a cable, and it is the first thing to try before paying for a faster plan.

Start time is free to change. Beginning the download before dinner means the file lands while the kitchen is busy and the television is off, and it finishes before the evening streaming block. Beginning it at nine at night means sharing the line with a 4K stream, which is the 1 hour 6 minute case from the section above.

One more check is worth the minute it takes: compare the reported speed with the clock. If a 5 GB file finishes in 30 minutes, the average was 40,000 / 1,800 = 22.2 Mbps, and if it finishes in 45 minutes the average was 14.8 Mbps. The clock is a better speed test than a speed test, because it measures the whole path rather than the best ten seconds of it.

Write the estimate on the back of an envelope as half an hour for 5 GB on a 25 Mbps line, and an hour when the television is on. The calculator at the top of this page will do it for any size and any speed, and every keystroke stays in the browser.