A 50 GB game on a 100 Mbps connection takes about an hour, not the eight minutes those two numbers suggest at a glance, and a download time calculator exists to settle that gap before the progress bar does. Connection speeds are sold in megabits. File sizes are counted in megabytes. The two differ by a factor of eight, and almost every wrong estimate starts there.
The download time calculator below takes a file size and a connection speed in whichever units they were quoted in, then answers in hours, minutes and seconds. Underneath it sits the arithmetic behind the factor of eight, the reason a real transfer runs slower than any calculator predicts, a reference table of common sizes against common speeds, and the short list of things that slow a download once the connection is no longer the limit.
Reading the file size off Windows? File Explorer reports sizes in binary units while download pages quote decimal ones, so a file described as 50 GB can be either of two slightly different figures. The storage unit converter shows both, and the tool below accepts either.
How to Use the Download Time Calculator
The download time calculator needs two figures and nothing else: the size of the file and the speed of the connection. Both fields accept a number typed with or without commas, and a unit typed after the figure is ignored rather than treated as an error. Every result updates as soon as either value changes.
The unit menus carry both families deliberately. Speeds sold by an internet provider are quoted in bits per second, so Kbps, Mbps and Gbps are grouped together, while the rate a browser or download manager displays on screen is in bytes per second and belongs under KB/s or MB/s. Picking the wrong group is the single most common way to end up with an answer that is eight times out.
The toggle beneath the fields decides which figure the headline shows. The full line speed is the pure arithmetic, with nothing else happening on the connection. A realistic 15% allowance subtracts a working margin for protocol overhead and normal contention, and the two lists below the panel follow whichever setting is active.
50 GB at 100 Mbps = 1 hour 6 minutes
That is 12.5 MB/s at the full line rate. Allowing 15% for overhead and everything else sharing the connection, expect closer to 1 hour 18 minutes., the line rate less the 15% allowance. With nothing else on the connection it would finish in 1 hour 6 minutes.
Enter a file size and a connection speed.
The full line speed is the arithmetic: file size divided by connection speed, with nothing else happening. The allowance covers protocol overhead and normal contention, and it is a rule of thumb rather than a measurement.
The same file at other connection speeds
How long 50 GB takes on the speeds most home connections are sold at.
- 5 Mbps 625 KB/s
- 22 hours 13 minutes
- 10 Mbps 1.25 MB/s
- 11 hours 6 minutes
- 25 Mbps 3.13 MB/s
- 4 hours 26 minutes
- 50 Mbps 6.25 MB/s
- 2 hours 13 minutes
- 100 Mbps 12.5 MB/s
- 1 hour 6 minutes
- 250 Mbps 31.25 MB/s
- 26 minutes 40 seconds
- 500 Mbps 62.5 MB/s
- 13 minutes 20 seconds
- 1 Gbps 125 MB/s
- 6 minutes 40 seconds
Other file sizes at this connection speed
How long each of these takes at 100 Mbps. The descriptions are typical sizes, not fixed ones.
- 100 MB App update
- 8 seconds
- 700 MB TV episode
- 56 seconds
- 5 GB Windows ISO
- 6 minutes 40 seconds
- 15 GB HD movie
- 20 minutes
- 25 GB 4K movie
- 33 minutes 20 seconds
- 50 GB Modern game
- 1 hour 6 minutes
- 100 GB Large game
- 2 hours 13 minutes
- 250 GB Game library
- 5 hours 33 minutes
Every figure above is the file size divided by the connection speed, converted once from bits to bytes. Speeds sold in megabits are decimal, so 100 Mbps is 100,000,000 bits a second and 12.5 MB/s of file data.
Megabits and Megabytes: Where the Factor of Eight Comes From
A bit is a single binary digit. A byte is eight bits, and it is the unit every file size on every operating system is counted in. Network speeds have been quoted in bits per second since long before home broadband existed, and storage has always been counted in bytes, so the two conventions meet in the middle of every download and disagree by a factor of eight.
Converting between them is one division. A 100 Mbps plan carries 100 million bits a second, which is 12.5 million bytes, so 12.5 MB of file data lands every second at the theoretical best.
| Advertised speed | File data per second |
|---|---|
| 25 Mbps | 3.125 MB/s |
| 50 Mbps | 6.25 MB/s |
| 100 Mbps | 12.5 MB/s |
| 300 Mbps | 37.5 MB/s |
| 500 Mbps | 62.5 MB/s |
| 1 Gbps | 125 MB/s |
In writing, the capital letter is the only thing separating the two. Mbps is megabits per second and describes a connection. MB/s is megabytes per second and describes a transfer. A speed test reports the first and a browser reports the second, which is why the download time calculator asks for the unit rather than guessing it.
Why a Download Time Calculator Estimate Is a Best Case
Any download time calculator answers one question: how long a given quantity of data takes to move at a given rate. It assumes the whole rate is available for that file, from start to finish, and that nothing else on the network wants a share. Real transfers rarely get that.
Part of the shortfall is fixed and can be worked out on paper. Data crosses a network in packets, and Cloudflare’s networking reference puts the standard maximum packet at 1,500 bytes with roughly 40 of those bytes spent on IP and TCP headers. Addressing therefore consumes a small percentage of the line before any file content moves, and the framing between a router and a PC takes a little more again.
The provider is usually not the reason for the rest. In the last full round of the FCC’s Measuring Broadband America testing, published in 2024 on data gathered in 2022, eight of the twelve provider and technology pairings measured hit 100% or better of their advertised download speed at peak hours. The other four managed 86% to 90%. The line generally supplies what it promises, and the rest of the path is where the time goes.
A 15% allowance is a reasonable working figure for that combined loss, which is why the calculator offers it as a setting rather than building it into every answer. It is a rule of thumb and not a measurement, and a well-connected machine pulling from a fast server will beat it.
How Long It Takes to Download Common File Sizes
These are the sizes people look up most, at the four connection speeds most home plans are sold at. Every figure is the file size divided by the line speed with no overhead allowance applied, so the download time calculator above will produce the same numbers for any combination not listed here.
| File size | 25 Mbps | 100 Mbps | 300 Mbps | 1 Gbps |
|---|---|---|---|---|
| 100 MB | 32 seconds | 8 seconds | 3 seconds | 1 second |
| 700 MB | 3 minutes 44 seconds | 56 seconds | 19 seconds | 6 seconds |
| 5 GB | 26 minutes 40 seconds | 6 minutes 40 seconds | 2 minutes 13 seconds | 40 seconds |
| 15 GB | 1 hour 20 minutes | 20 minutes | 6 minutes 40 seconds | 2 minutes |
| 25 GB | 2 hours 13 minutes | 33 minutes 20 seconds | 11 minutes 7 seconds | 3 minutes 20 seconds |
| 50 GB | 4 hours 26 minutes | 1 hour 6 minutes | 22 minutes 13 seconds | 6 minutes 40 seconds |
| 100 GB | 8 hours 53 minutes | 2 hours 13 minutes | 44 minutes 27 seconds | 13 minutes 20 seconds |
| 250 GB | 22 hours 13 minutes | 5 hours 33 minutes | 1 hour 51 minutes | 33 minutes 20 seconds |
Doubling the connection speed halves the time, and the relationship holds all the way down the column, so a figure for 50 Mbps is the 25 Mbps time cut in half. That makes the table usable for speeds it does not list.
How Long Does It Take to Download a Game?
Modern console and PC titles commonly run between 40 GB and 150 GB, and the largest sit above that once high resolution texture packs are included. At 100 Mbps a 50 GB game arrives in a little over an hour, a 100 GB game in a little over two, and the same downloads on a 25 Mbps connection take four and nine hours respectively.
Two things regularly make a game slower than the figures above, which is why a download time calculator gives the floor rather than the finish time on launch day. Storefronts apply their own per-account or per-region limits during a busy release, capping the transfer well below the line speed. Day-one patches then download separately after the base install finishes, so the total wait can exceed the size shown on the store page.
A console on Wi-Fi is the usual bottleneck. Games consoles are often the furthest device from the router and the least likely to be wired, and a weak signal caps the transfer regardless of the speed the plan provides. Moving that one device to ethernet is the single largest improvement available for large downloads.
What Actually Slows a Download Down
Once the arithmetic is settled, the remaining difference between the download time calculator’s estimate and the progress bar comes from the path between the server and the disk. Each of the following is capable of setting the ceiling on its own, and the slowest one in the chain wins.
- Wi-Fi rather than ethernet. A weak or congested wireless signal delivers a fraction of the line speed, and it is the most common single cause of a download running well under the plan.
- The server at the other end. A download source with its own per-connection cap will hold the transfer at that cap no matter how fast the connection is.
- Other devices on the same connection. Streaming, backups and cloud sync all take a share, and a household connection is divided among everything using it.
- Peak evening hours. Shared infrastructure carries the most traffic between roughly 7 pm and 11 pm, which is the window the FCC’s own testing uses for the same reason.
- Disk write speed. Rare on a gigabit connection and possible on a fast one, where a mechanical hard drive or a full SSD cannot accept data as quickly as the network delivers it.
- A VPN or a proxy. Encryption overhead and a longer route both cost throughput, sometimes heavily depending on the server chosen.
What a Download Time Calculator Cannot Tell You
A download time calculator converts a file size and a connection speed into a duration, and that answer is exact for the arithmetic it performs. Divide the speed by eight when it is quoted in megabits, allow 10% to 20% for overhead and contention, and the result is close enough to plan around. What it cannot see is the rest of the path.
It has no way of knowing what the server at the other end will allow, how much of the connection the rest of the household is already using, or whether the device is on ethernet or three rooms away from the router. Those set the real speed, and none of them appear in the two numbers a calculator is given.
The practical use for the estimate is comparison rather than prediction. A transfer running at roughly the pace the download time calculator predicted is behaving normally, and one running at a fraction of it points at something specific to check, starting with whether the machine is on Wi-Fi and finishing with the source it is pulling from.