Download Time Calculator
Download time is the file size in megabits divided by your speed in Mbps. A 1 GB file is 8,000 megabits, so at 100 Mbps it takes 8,000 ÷ 100 = 80 seconds (see it worked out). Fill in any two of size, speed and time to get the third.
Fill in any two, get the third
Leave blank the one you want to find: the time, the speed you need, or how much fits. The answer updates as you type.
Check your input
The same download at other speeds
Your speed Tap a row to try itHow to Use This Calculator
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Fill in two values
Type the file size and your internet speed to get the time. Or type a size and a time to find the speed you need, or a speed and a time to see how much you can download.
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Read the answer
The empty value is worked out and marked as the answer. Times are shown in hours and minutes, with the clock time the download would finish if you start now.
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Compare speeds
The ladder shows the same file at other speeds. Tap a row to try it. Set the efficiency to 90% for a realistic estimate, or pick GiB to match Windows.
How to calculate download time
Internet speeds are sold in megabits per second (Mbps), but file sizes are given in megabytes (MB) or gigabytes (GB). A byte has 8 bits, so first turn the file size into megabits by multiplying by 8. Then divide by the speed. The same relationship gives all three answers:
Take a 100 GB game on a 300 Mbps plan. 100 GB is 100,000 MB, which is 800,000 megabits. Dividing by 300 gives 2,666.67 seconds, or about 44 min 27 s. That is the best case, with the connection running at full speed the whole time.
Show a 100 GB game at 300 Mbps
Mbps and MB/s are not the same
The lowercase b in Mbps means bits; the capital B in MB/s means bytes. Download apps and browsers usually show MB/s, while your internet provider quotes Mbps. To turn one into the other, divide or multiply by 8:
| Plan speed | Download rate | 1 GB takes |
|---|---|---|
| 10 Mbps | 1.25 MB/s | 13 min 20 s |
| 25 Mbps | 3.125 MB/s | 5 min 20 s |
| 50 Mbps | 6.25 MB/s | 2 min 40 s |
| 100 Mbps | 12.5 MB/s | 1 min 20 s |
| 300 Mbps | 37.5 MB/s | ≈ 26.67 s |
| 500 Mbps | 62.5 MB/s | 16 s |
| 1 Gbps | 125 MB/s | 8 s |
| 2 Gbps | 250 MB/s | 4 s |
Download time chart
The chart gives download times at full speed for common file sizes. Times are rounded to the second, and a rounded time starts with ≈. Sizes are decimal (1 GB = 1,000 MB), which is how most stores and download pages list them.
Swipe the chart sideways to see more speeds.
| File size | 25 Mbps | 50 Mbps | 100 Mbps | 300 Mbps | 1 Gbps |
|---|---|---|---|---|---|
| 1 GB | 5 min 20 s | 2 min 40 s | 1 min 20 s | ≈ 26.67 s | 8 s |
| 5 GB | 26 min 40 s | 13 min 20 s | 6 min 40 s | ≈ 2 min 13 s | 40 s |
| 10 GB | 53 min 20 s | 26 min 40 s | 13 min 20 s | ≈ 4 min 27 s | 1 min 20 s |
| 25 GB | 2 h 13 min 20 s | 1 h 6 min 40 s | 33 min 20 s | ≈ 11 min 7 s | 3 min 20 s |
| 50 GB | 4 h 26 min 40 s | 2 h 13 min 20 s | 1 h 6 min 40 s | ≈ 22 min 13 s | 6 min 40 s |
| 100 GB | 8 h 53 min 20 s | 4 h 26 min 40 s | 2 h 13 min 20 s | ≈ 44 min 27 s | 13 min 20 s |
| 150 GB | 13 h 20 min | 6 h 40 min | 3 h 20 min | 1 h 6 min 40 s | 20 min |
Everyday downloads
File sizes vary a lot, so check the real size on the store or download page. These example sizes give a feel for the range, from a phone photo to a large game:
| Example file | Size | At 50 Mbps | At 300 Mbps |
|---|---|---|---|
| A phone photo | 4 MB | 0.64 s | ≈ 0.11 s |
| A song | 8 MB | 1.28 s | ≈ 0.21 s |
| A 700 MB video | 700 MB | 1 min 52 s | ≈ 18.67 s |
| An HD movie | 4 GB | 10 min 40 s | ≈ 1 min 47 s |
| A 4K movie | 20 GB | 53 min 20 s | ≈ 8 min 53 s |
| A large game | 100 GB | 4 h 26 min 40 s | ≈ 44 min 27 s |
Large games are the downloads people plan around. A game update can be a few gigabytes or as big as a new game, so it is worth checking its size before you start one in the evening. If a download will run for hours, start it before bed and let it finish overnight.
Show a 20 GB 4K movie at 100 Mbps
What internet speed do I need to download a file?
Turn the question around: divide the file size in megabits by the time you have, in seconds. To get a 100 GB game overnight, in 8 hours (28,800 seconds), you need 800,000 ÷ 28,800 ≈ 27.78 Mbps. To get it within an hour you need about 222.22 Mbps. Leave the speed blank in the calculator and it works this out for you, in whichever unit you pick.
Show the speed for 100 GB in 8 hours
Plan for some headroom. If the calculator says you need 200 Mbps, a 200 Mbps plan is cutting it close, because real downloads rarely hold the full plan speed (see below). With the efficiency set to 90%, the calculator raises the speed you need to cover that.
How much can you download in an hour?
Multiply the speed by 3,600 seconds and divide by 8 to get megabytes. At 100 Mbps that is 100 × 3,600 ÷ 8 = 45,000 MB, or 45 GB per hour at full speed.
| Speed | Per hour | Per day |
|---|---|---|
| 10 Mbps | 4.5 GB | 108 GB |
| 25 Mbps | 11.25 GB | 270 GB |
| 50 Mbps | 22.5 GB | 540 GB |
| 100 Mbps | 45 GB | 1.08 TB |
| 300 Mbps | 135 GB | 3.24 TB |
| 500 Mbps | 225 GB | 5.4 TB |
| 1 Gbps | 450 GB | 10.8 TB |
Show how much 100 Mbps downloads in an hour
Why downloads take longer than the calculator says
At 100% the calculator assumes your connection carries file data at the full plan speed from the first second to the last. Real downloads lose some of that:
- Every packet carries headers as well as data. With the usual 1,500-byte packets, 1,460 bytes of each 1,538 sent over Ethernet are file data, which is about 94.9%.
- Wi-Fi is usually slower than a cable, and walls and distance from the router make it worse.
- Other people and devices on your network share the same connection.
- The server you download from may send slower than your line can receive, especially when many people download the same thing at once.
- Plans are sold as "up to" a speed, and busy evening hours can bring it down.
Set the efficiency to 90% for a typical home connection, or lower on busy Wi-Fi. The same 100 GB game at 300 Mbps then takes about 49 min 23 s instead of 44 min 27 s. For your own number, run a speed test, then type the result in as the speed with the efficiency at 100%.
Show the game at 90% efficiency
Why the time left keeps changing
A download app works out the time left from how fast the file is arriving right now. When the rate drops for a few seconds, the estimate jumps up; when it picks up, the estimate falls. The calculator does the same sum with a steady speed, so its answer sits in the middle of those swings. If the app shows a rate in MB/s, type that rate in with MB/s as the unit and the size that is left, and you get a steadier estimate.
GB or GiB: why Windows shows a smaller number
There are two ways to count a gigabyte. In decimal units, which drive makers, stores and most download pages use, 1 GB is 1,000,000,000 bytes. In binary units, 1 GiB (gibibyte) is 1,073,741,824 bytes, 2 to the power of 30. Windows counts in binary units but still writes "GB". That is why a 1 TB drive shows up as about 931.32 GB in Windows, and a 100 GB download as about 93.13 GB.
The difference grows with size: about 2.4% for kilobytes, 7.4% for gigabytes and 10% for terabytes. If you copy a size from Windows into the calculator, pick GiB so the time matches. Speeds are not affected: 1 Mbps is always 1,000,000 bits per second.
Downloading several files at once
Running several downloads side by side does not make the whole batch finish sooner, because they all share one connection. Add up the sizes and use the total. Three files of 20 GB each are 60 GB, which takes 1 h 20 min at 100 Mbps whether you download them one after another or all together. Running them together can help when a single server sends slowly, since each one then adds its own share.
Speed and size units
Speeds count bits, sizes count bytes, and each step up is 1,000 times bigger. These are the units the calculator accepts:
| Unit | Name | Equals |
|---|---|---|
| Kbps | kilobits per second | 1,000 bits/s |
| Mbps | megabits per second | 1,000,000 bits/s |
| Gbps | gigabits per second | 1,000 Mbps |
| KB/s | kilobytes per second | 8 Kbps |
| MB/s | megabytes per second | 8 Mbps |
| GB/s | gigabytes per second | 8 Gbps |
| MB | megabyte | 1,000,000 bytes |
| GB | gigabyte | 1,000 MB |
| GiB | gibibyte | 1,073,741,824 bytes |
A quick check for any pair of units: if the speed is in MB/s and the size in MB, no conversion is needed at all. A 600 MB file at 12 MB/s takes 600 ÷ 12 = 50 seconds. The factor of 8 only comes in when one side counts bits and the other counts bytes.
Upload time
Uploading uses the same formula with your upload speed. On many cable and DSL plans the upload speed is much lower than the download speed, so sending a file can take several times longer than receiving it. Type your upload speed into the calculator to see how long a backup or a video upload will take.
Sources
- NIST, Definitions of the SI units: the binary prefixes: kilo means 1,000, and the binary prefixes (KiB, MiB, GiB) the IEC approved in 1998.
- Apple Support, How storage capacity is measured on Apple devices: decimal and binary gigabytes side by side.
Frequently Asked Questions
How long does it take to download 1 GB?
1 GB is 8,000 megabits, so it takes 5 min 20 s at 25 Mbps, 1 min 20 s at 100 Mbps and 8 s at 1 Gbps, at full speed. Real downloads usually take a little longer.
How long does it take to download 100 GB at 100 Mbps?
2 h 13 min 20 s at full speed. 100 GB is 800,000 megabits, and 800,000 ÷ 100 = 8,000 seconds. At a more realistic 90% of the plan speed it takes about 2 h 28 min 9 s.
How do you calculate download time?
Multiply the file size in megabytes by 8 to get megabits, then divide by your speed in Mbps. The answer is in seconds. A 700 MB file is 5,600 megabits, so at 50 Mbps it takes 5,600 ÷ 50 = 112 seconds, or 1 minute 52 seconds.
How many MB/s is 100 Mbps?
12.5 MB/s. Divide Mbps by 8, because a byte has 8 bits. 300 Mbps is 37.5 MB/s and 1 Gbps is 125 MB/s. Download apps usually show MB/s, while internet plans are sold in Mbps.
What internet speed do I need to download 50 GB in an hour?
About 111.11 Mbps at full speed. 50 GB is 400,000 megabits and an hour is 3,600 seconds, so 400,000 ÷ 3,600 ≈ 111.11. To allow for real-world losses, pick a plan of about 123 Mbps or more.
Why is my download slower than my internet speed?
Part of every connection carries packet headers instead of file data, and Wi-Fi, other devices on your network and the server you download from can all hold the speed down. Plans are also sold as "up to" a speed. Set the efficiency to 90% or 80% for a more realistic time.
Why does Windows show a smaller size than the download page?
Windows counts in binary units, where 1 GB means 1,073,741,824 bytes (properly called a GiB), while most download pages use 1 GB = 1,000,000,000 bytes. A 100 GB download shows as about 93.13 GB in Windows. Pick GiB in the calculator to match what Windows shows.