# How to measure bandwith

• Newbie
• Posts: 6
• Loc: Chicago, IL

3+ Months Ago

Wasn't sure which section to post this in?

My question is how exactly does one go about measuring bandwith.

Say, on an 8mb file viewed 20,000 times in a daily period. What does it equal in bandwith??

I know it's like measuring the speed in which files are transfered. But how exactly is it measured. I'm lost...
• Expert
• Posts: 526
• Loc: St. John's, Newfoundland, Canada

3+ Months Ago

That is a difficult question. No one can give you an exact answer without knowing a great deal about your network. For example, a compressed line will reduce bandwidth consumption. The 8MB file in question often called the "payload". In addition to payload data, other information such as packet headers and parity bits consume bandwidth.

By 8mb, I'm assuming you meant 8MB (big difference). 8MB is eight million bytes. Bandwidth is frequently measured in bytes per second because transmission lines frequently transmit in serial (rather than parallel).

You convert bytes to bits (8MB to 64Mb) by multiplying by the number of bits in a byte (usually . Since non-payload data increases your file size, I like to go with a factor of 10. It seems fairly accurate.

8MB * 10 * 20,000 = 1,600,000 Mb/"elapsed time"

That's an enourmous amount of bandwidth... that can't be the number of downloads you're dealing with!
• Newbie
• Posts: 6
• Loc: Chicago, IL

3+ Months Ago

Yes, I've realized it is hard to get a good answer on bandwith. Everyone has a different answer.

The file in question actually is 8,839KB.

I'm linking a video file from my site to a very popular site. When I asked the webmaster how much of my bandwith their user's would probably take up the response was "say 8meg x 20,000"

I have 20gig transfer right now with about 16-17 available. I've been trying to formulate myself and can't seem to get it right, so I'm on a search to figure it out.

As this is only going to be the first out of many that bandwith will be an issue. Finding a good formula to work with will be extremely valuable.
• Genius
• Posts: 5731
• Loc: Sub-level 28

3+ Months Ago

You've already got the formula, you gave it to us

This is why most hosts don't allow hosting of videos, music or CD ISO's (aside from potential copyright infringements, they're hell on bandwidth).
• Newbie
• Posts: 6
• Loc: Chicago, IL

3+ Months Ago

Aren't you supposed to add the amount of time in there? Since it's based on the transfer speed, kinda like mph when driving?
• Genius
• Posts: 5731
• Loc: Sub-level 28

3+ Months Ago

Quote:
Say, on an 8mb file viewed 20,000 times in a daily period. What does it equal in bandwith??

1 Day. So that'd be 160Gig/day. * 30 (days in a month average), 4.8 Terrabytes/month.

So, you're probably looking at about a grand a month in bandwidth fees for 5TB/mo
• Newbie
• Posts: 6
• Loc: Chicago, IL

3+ Months Ago

Oh yeah, I know there is no way for me to personally host this video, that's why I'm trying to get a good formula for future reference.

Also found this site, which is very helpful
• Posts: 121
• Loc: North of Boston

3+ Months Ago

go to google and type in measure bandwith sand there a websites but most charge \$\$
• Expert
• Posts: 526
• Loc: St. John's, Newfoundland, Canada

3+ Months Ago

• Professor
• Posts: 794
• Loc: California

3+ Months Ago

I thought maybe you guys were talking about your personal thru put to the internet. For that I just do a google search on "internet speed test" dslreports gives you your up and download speeds where cnet just seems to give you the download speed. Hope this helps somebody
• Moderator
• Posts: 2696
• Loc: Somewhere outside the box in Sarasota, FL.

3+ Months Ago

Hmm, well it depends on what level of access you have to the serving infrastructure. If you can install a box (running *nix of some kind) you can query your router using MRTG, http://www.mrtg.org.

Though configuration you can determine bandwidth utilization, and what not. It's handy for grepping through the logs and extracting what you find important -- such as bandwidth utilization over a period of time.

Cheers.
• Born
• Posts: 3

3+ Months Ago

How is transfer measured?

Formula: page size x page views X 30days=Bandwidth Transfer
Page size:You have 10KB of text,60 KB of gifs would equal a per page size of 70K.

Page views: you have 60 vistors that look at 4 pages per day equals 240 views a day.
70x240x30(days)=504,000 kb or approximately 504 mb, of bandwidth each month.

One megabyte (MB) is equal to apx. 1,000 kilobytes
• Expert
• Posts: 526
• Loc: St. John's, Newfoundland, Canada

3+ Months Ago

Daemonguy wrote:
If you can install a box (running *nix of some kind) you can query your router using MRTG, http://www.mrtg.org.

Daemonguy has a good point. This is a great historical measurement that records all traffic, not use content. Note: there is a difference between what you serve (payload data / content) and the amount of data sent out the pipe (raw data).

grace5 wrote:
70x240x30(days)=504,000 kb or approximately 504 mb, of bandwidth each month. One megabyte (MB) is equal to apx. 1,000 kilobytes

Grace5's formula is incorrect. It doesn't account for all traffic that is likely included in your fees and the total KB must be taken from the actual file size, not the space used on disk. Furthermore, one megabyte (MB) is equal to exactly 1024 kilobytes (KB).

For the record:
Megabytes (MB)
Megabits (Mb)
Kilobytes (KB)
Kilobits (Kb)

(Its a little pet peeve, lol.)

I searched for several days for a semi-reliable formula to estimate traffic on a typical network given specific file sizes without success. Your best bet is using historical data to estimate future loads. (A.K.A. go ask your router as Daemonguy suggested.)
• Born
• Posts: 3

3+ Months Ago

Quote:
It doesn't account for all traffic that is likely included in your fees

well if you really want true figure better count what traffic you are getting in SMTP and other Ports
• Expert
• Posts: 526
• Loc: St. John's, Newfoundland, Canada

3+ Months Ago

grace5 wrote:
well if you really want true figure better count what traffic you are getting in SMTP and other Ports

Yes, exactly why you should be looking at router stats.
• Born
• Posts: 3

3+ Months Ago

My formula is close enough to be correct (unless you want to split hairs) and BTW I stated 1 gb is APX 1000 mb

• Genius
• Posts: 13511
• Loc: Florida

3+ Months Ago

i wonder if anyone ever takes queryStrings and post data into consideration?

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