Bandwidth Calculator
Get the download time for a file at a connection speed, or the speed a file needs to arrive within a set time. File sizes go from bits to TB and speeds from bps to Gbps. The Data Usage mode turns an average speed and your hours of use into data per hour, per day and per month, and checks the month against a data cap.
File sizes here step by 1,024, so 1 GB is 1,073,741,824 bytes. Speeds step by 1,000, so 1 Mbps is 1,000,000 bits per second.
How to use the Bandwidth Calculator
- Choose Download Time to get the time a file takes at a speed you know. Choose Required Speed to get the speed a file needs to finish in a time you set. Choose Data Usage to get the data an average speed uses per hour, per day and per month.
- For Download Time or Required Speed, enter the file size and pick its unit: bits, bytes, KB, MB, GB or TB.
- For Download Time, enter the connection speed and pick bps, Kbps, Mbps or Gbps. For Required Speed, enter the desired transfer time and pick seconds, minutes, hours or days.
- For Data Usage, enter the average speed and pick its unit, then the hours of use per day and the days per month. The days field starts at 30. If your plan has a data cap, enter it and pick GB or TB. Leave that field empty if there is no cap.
- Press the Calculate button. To try other numbers, change any value and press the button again. If a value is missing or out of range, a message under the button names the field to fix.
- Read the result. Under Download Time and Required Speed, the Reference speeds list gives the time for the same file at five fixed speeds, or says whether each of those speeds is enough. Data Usage shows data per month first, then data per hour and per day. With a cap it adds the share of the cap used and the days of use until the cap is reached.
The bandwidth math
Download time in seconds = file size in bits ÷ speed in bits per second Required speed in bits per second = file size in bits ÷ time in seconds Data per hour in bytes = speed in bits per second × 3,600 ÷ 8 Data per day = data per hour × hours of use per day Data per month = data per day × days per month
The calculator turns both inputs into bits first. A byte is 8 bits. File size units step by 1,024, so 1 KB is 1,024 bytes, 1 MB is 1,048,576 bytes and 1 GB is 1,073,741,824 bytes. Speed units step by 1,000, so 1 Mbps is 1,000,000 bits per second and 1 Gbps is 1,000,000,000. That makes 100 Mbps equal to 12,500,000 bytes per second, which is 11.92 of the file size field's MB per second and not 12.5. A time under 60 seconds prints in seconds, under 60 minutes in minutes, under 24 hours in hours, and anything longer in days. A required speed prints in Gbps from 1,000,000,000 bits per second, in Mbps from 1,000,000, in Kbps from 1,000 and in bps below that. Data Usage counts bytes in steps of 1,000 instead, so its 1 GB is 1,000,000,000 bytes and its 1 TB is 1,000 GB, for the results and for the cap. It prints a figure under 1,000 bytes in bytes, under 1,000,000 bytes in kB, under 1,000,000,000 bytes in MB and anything larger in GB. The share of the cap is data per month ÷ cap, and the days of use until the cap is reached are cap ÷ data per day. In all three modes the calculator works with the numbers as you typed them and rounds each printed figure to two decimals, with a half rounding up. A figure above 1 trillion prints as over 1 trillion, and a time or speed that would round to 0 prints as under 0.01.
Worked example
Choose Download Time, enter 4 as the file size and pick GB, enter 100 as the connection speed and pick Mbps, then press Calculate. The calculator shows "Download time at 100 Mbps: 5.73 min". It reads 4 GB as 4 × 1,073,741,824 bytes, which is 34,359,738,368 bits, and 100 Mbps as 100,000,000 bits per second. 34,359,738,368 ÷ 100,000,000 = 343.6 seconds, and 343.6 ÷ 60 = 5.73 minutes. Under Reference speeds the same file takes 7.1 days at 56 Kbps, 22.91 min at 25 Mbps, 2.86 min at 200 Mbps and 34.36 sec at 1 Gbps. Now choose Required Speed, keep 4 GB, enter 10 as the desired transfer time, pick minutes and press Calculate. 34,359,738,368 bits ÷ 600 seconds gives "Required speed: 57.27 Mbps".
Monthly data usage from a speed
The Data Usage mode answers how much data a connection moves when it runs at one speed for a set time. Enter the average speed, the hours of use per day and the days per month. The calculator returns data per hour, per day and per month.
Enter the rate the data flows at, not the top speed of the plan. A 100 Mbps line that carries a 5 Mbps stream uses data at 5 Mbps.
This mode counts 1 GB as 1,000,000,000 bytes and 1 TB as 1,000 GB. The file size field of the other two modes counts 1 GB as 1,073,741,824 bytes, so a GB there is 73,741,824 bytes larger.
Hours per day run from 0 to 24 and days per month from 0 to 31. Outside those ranges the calculator shows a message and no result. A speed of 0 is allowed and gives 0 bytes. A cap has to be above 0.
Worked example: 25 Mbps for 4 hours a day
Choose Data Usage, enter 25 as the average speed and keep Mbps, enter 4 as the hours of use per day and leave the days per month at 30. Press Calculate. The calculator shows "Data per month: 1,350 GB", with 11.25 GB as data per hour and 45 GB as data per day.
25 Mbps is 25,000,000 bits per second. Times 3,600 seconds and divided by 8 bits per byte, that is 11,250,000,000 bytes per hour, or 11.25 GB. 11.25 × 4 = 45 GB per day, and 45 × 30 = 1,350 GB per month.
Now enter 1000 as the data cap, keep GB and press Calculate again. Share of the cap used reads 135%. Days of use until the cap is reached reads 22.22, because 1,000 ÷ 45 = 22.22. Below that the calculator says "The month goes over the cap by 350 GB. The cap is reached during day 23." The 1,000 GB is an example. Enter the cap your provider states.
Data per hour that Netflix states
Netflix lists data used per hour, per device, on its help page "How to control how much data Netflix uses". For its High setting the page gives up to 1 GB in standard definition, up to 3 GB in high definition and up to 7 GB in 4K ultra high definition. For Low it gives up to 0.3 GB and for Medium up to 0.7 GB. Checked on 14 October 2026. The page does not say how many bytes Netflix counts as a GB.
To use one of these figures in the calculator, turn it into a speed. GB per hour × 8,000 ÷ 3,600 gives Mbps when a GB is 1,000,000,000 bytes, so 3 GB per hour is 6.67 Mbps. Enter 6.67 Mbps and the calculator shows 3 GB as data per hour. With 2 hours a day over 30 days it shows 6 GB per day and 180.09 GB per month. The extra 0.09 GB comes from rounding the speed to 6.67.
Source of the Netflix figures, checked on 14 October 2026:
Frequently asked questions
How long does it take to download 1 GB at 100 Mbps?
The calculator gives 1.43 min. It reads 1 GB as 1,073,741,824 bytes, which is 8,589,934,592 bits, and 100 Mbps as 100,000,000 bits per second. 8,589,934,592 ÷ 100,000,000 = 85.9 seconds, which it prints as 1.43 min.
What is the difference between Mbps and MB per second?
Mbps counts bits and MB counts bytes, and a byte is 8 bits. For a file size the calculator also steps the two differently: 1 Mbps is 1,000,000 bits per second, while 1 MB of file size is 1,048,576 bytes. So 100 Mbps is 12,500,000 bytes per second, or 11.92 MB per second in the file size field's units. A 12.5 MB file at 100 Mbps prints as 1.05 sec and not as 1 sec.
Does the bandwidth calculator use 1,000 or 1,024?
It uses both. File sizes in Download Time and Required Speed step by 1,024: 1 KB is 1,024 bytes, 1 MB is 1,024 KB, 1 GB is 1,024 MB and 1 TB is 1,024 GB. Speeds step by 1,000: 1 Kbps is 1,000 bps, 1 Mbps is 1,000 Kbps and 1 Gbps is 1,000 Mbps. A 1 GB file at 1 Gbps therefore prints as 8.59 sec and not as 8 sec. NIST lists 1 GB as 1,000,000,000 bytes and 1 GiB as 1,073,741,824 bytes, so the file size field's GB is the size NIST calls a GiB. If your file size was counted with 1,000 bytes to the KB, enter the size in bytes. Data Usage steps by 1,000 throughout, so its 1 GB is 1,000,000,000 bytes.
How do I find the speed I need for a file?
Choose Required Speed, then enter the file size and the time you want the transfer to take. The calculator divides the bits by the seconds. A 4 GB file in 10 minutes needs 57.27 Mbps. In this mode the Reference speeds list marks each of its five fixed speeds as Sufficient or shows the time that speed would need.
How much data does 25 Mbps use per hour?
11.25 GB, if data flows at 25 Mbps for the whole hour. 25 Mbps is 25,000,000 bits per second and an hour has 3,600 seconds, which makes 90,000,000,000 bits or 11,250,000,000 bytes. The Data Usage mode counts 1 GB as 1,000,000,000 bytes and prints 11.25 GB. A 25 Mbps plan that sits idle uses nothing, so enter the rate you use and not the top speed of the plan.
How many GB is a month of streaming at 5 Mbps?
At 5 Mbps the Data Usage mode gives 2.25 GB per hour. With 2 hours a day over 30 days that is 4.5 GB per day and 135 GB per month. With 4 hours a day it is 9 GB per day and 270 GB per month. The 5 Mbps is an example. Enter the rate of your own stream.
How long until I reach my data cap?
Choose Data Usage and enter the cap in the Data Cap field, in GB or TB. The calculator divides the cap by the data per day and prints the days of use until the cap is reached, next to the share of the cap the month uses. At 25 Mbps for 4 hours a day, a 1,000 GB cap lasts 22.22 days of use. The cap is reached during day 23, and 30 days use 135% of it. If no data is used, the row reads never.
What are the reference speeds under the result?
They are five fixed speeds that Download Time and Required Speed repeat the result for: 56 Kbps labeled Dial-up, 25 Mbps labeled DSL, 200 Mbps labeled Cable, and 1 Gbps labeled Fiber and again labeled 5G. They are round numbers set in the calculator. They are not measurements of any provider or line, so enter your own speed for a result that fits your connection.
What does the download time assume?
It assumes the connection holds the speed you enter from the first bit to the last and carries nothing but this file. The calculator adds no time for protocol overhead, pauses or a slower server. For an upload, enter your upload speed as the connection speed. The math is the same, and the result line still reads Download time.