When researching web host providers to house your site, one of the important factors to evaluate is the cost for your required amount of bandwidth,

Yes, many providers offer “unlimited” plans, but upon taking a closer look, you’ll find that unlimited isn’t truly unlimited – there are always penalties if you use too much as is based on a “normal” usage, whatever that means. That said, knowing how much bandwidth your site truly requires can be a bit of an art form.

So what exactly is bandwidth, anyway?

bandwidth calculation Essentially, it’s just a term to quantify the rate of traffic and data allowed to flow between users and your site via the internet.

The term “bandwidth” is loosely use to describe “data transfer” but in reality these two are two different things. Bandwidth is the measure of maximum data that can be transferred in a given time, usually measured in seconds. Data transfer, on the other hand, is the amount of data to be transferred; while bandwidth is the rate of the data transfer. You can imagine bandwidth as the width of a water pipe where data transfer is the amount of water flowing out from the pipe. How wide is the pipe width (bandwidth) determines how fast can water (data) flows. Fundamentally, data transfer is the consumption of bandwidth.

To site owners, the amount of bandwidth that a hosting company site offers can typically serve as a good indicator of that host’s capabilities – the higher the bandwidth, the better the speed; network; connectivity; and systems.

Nothing in Life Comes Free – Let’s Explore Unlimited Bandwidth

As mentioned above, many hosting organization offer unlimited plans that include “unlimited bandwidth.” To the purchaser, this means that they can run as much data and as much traffic to their site as they need without ceilings. To the hosting provider, it means a way to give a flat cost to a buyer that generally will work.

As ever, the truth lies somewhere in the middle.

Simply put, it’s just impossible for hosting companies to offer unlimited bandwidth (which is why unlimited bandwidth/storage is #1 among all silly hosting features) – it’s too expensive to provide unbridled access to every customer. That said, most companies fall somewhere into a “normal range” of bandwidth use by default, and this range is what hosting providers use when creating their “unlimited” packages. By “unlimited,” hosting providers can cater to the majority of their client base – however, there absolutely is a ceiling on the bandwidth included in that package cost; the trick is to know what it is.

By comparing your site’s actual required bandwidth with the bandwidth offered in that “unlimited” guise, you can better determine which level of hosting you truly need and whether a given provider will truly meet your needs.

How to Calculate the Bandwidth you Need

Formula used to calculate needed website bandwidth.

Formula used to calculate needed website bandwidth is not that complicated!

Think about bandwidth like a pair of pants: you need the size that you need. It doesn’t make a whole lot of sense to buy up a size, but at the same point, there’s a number that fits. If your waist is a size 36, you simply aren’t going to fit into that 32. Simple math.

Basic Bandwidth Calculation / Guesstimation

In bandwidth, it also doesn’t make sense to purchase up – this is why it makes sense to work with hosting providers who offer scalable solutions. As for buying small, that’ll only get you into trouble. Know your actual need to get the service that works for you – here’s how to calculate your required bandwidth:

  1. Estimate the average page size of your site in kilobytes (KB).*
  2. Multiply that average page size (in KB) by the monthly average number of visitors.
  3. Multiply the result from step 2 by the average number of pageviews per visitor.

* If you don’t know, use Pingdom’s Load Time test on a few pages and take the average of those tested pages for your base testing number.

This is the base of knowing your required bandwidth – however, you’re not done quite yet. You also need to include an allocation for extra “room” in case your traffic spikes. Generally speaking, I recommend giving at least a 50 percent spread. But you need to allocate extra room to grow and traffics spikes – leave at least 50% tolerance.

Needed Website Bandwidth + Redundancy (without user downloads)

To do this calculation, use the following formula:

Bandwidth needed = Average Page Views x Average Page Size x Average Daily Visitors x Number of days in a month (30) x Redundant Factor

  • Average Daily Visitors: The total number of monthly visitors/30.
  • Average Page Size: The average size of your web page.
  • Average Page Views: The average page viewed per visitors.
  • Redundant Factor: A safety factor ranged from 1.3 – 1.8.

Needed Website Bandwidth + Redundancy (with user downloads)

If your site does not use or allow downloads:

Bandwidth needed = [(Average Page Views x Average Page Size x Average Daily Visitors) + (Average Download per day x Average File Size) ] x Number of days in a month (30) x Redundant Factor

  • Average Daily Visitors: The total number of monthly visitors/ 30.
  • Average Page Size: The average size of your web page
  • Average Page Views: The average page viewed per visitor
  • Average File Size: The total file size divided to the number of files
  • Redundant Factor: A safety factor ranged from 1.3 – 1.8.

How Does This Affect your Web Hosting Selection?

Once you know how much bandwidth you need, you can better shop for a web host that is likely to be a good fit for you and your site’s needs. As you evaluate hosting organizations, carefully examine the bandwidth allocated in each of their plans. If you are considering an unlimited plan, dig carefully to learn the allowed bandwidth that they will accommodate in that plan. Know that many hosting providers will not share their exact threshold upfront – you may have to dig and, even then, some will not quantify it for you. I always believe that transparency is important in business so if you can’t learn the allowed bandwidth included in the unlimited plan, you may want to raise a red flag.

That said, most providers will share this information with you and you can use it, paired with your own bandwidth requirement, to make the best possible hosting environment decision for your business’ site.