A/B Testing Bandwidth Cost (Monthly) Calculator
Estimate the extra monthly bandwidth and delivery cost created by serving an A/B test payload to part of your website traffic.
Overview
This A/B testing bandwidth cost calculator estimates the additional data transfer and monthly delivery cost of an experiment. Enter your monthly visitor volume, average eligible page views, test allocation, extra payload size, and bandwidth rate to estimate the incremental cost.
How it works
The calculator estimates eligible page views by multiplying monthly visitors by average page views per visitor. It then applies the test traffic allocation to find the number of test exposures. That exposure count is multiplied by the additional payload size, converted from KB to GB, and multiplied by your stated bandwidth price. This estimates the incremental transfer cost, rather than the total cost of delivering your website.
How to use this calculator
- 1Enter your estimated monthly unique visitor count.
- 2Add the average number of eligible page views per visitor.
- 3Set the percentage of traffic included in the experiment.
- 4Enter the extra payload downloaded for each test page view in KB.
- 5Add your CDN or hosting bandwidth price per GB and review the estimated cost.
Example Calculation
Monthly visitors
100000
Average page views per visitor
4
Test traffic allocation
50%
Additional test payload per page view
150
Bandwidth cost per GB
$0
Estimated monthly A/B test bandwidth cost
$2.40
With 100,000 visitors, four eligible page views each, 50% test allocation, and a 150 KB extra payload, the test creates about 30 GB of extra monthly transfer, estimated at $2.40 per month.
Frequently asked questions
What counts as an A/B test payload?
It is any extra data delivered because of the experiment, such as testing scripts, variant images, feature assets, personalization data, or additional markup.
Does this calculate my website's total bandwidth cost?
No. It estimates only the incremental bandwidth associated with the additional experiment payload. Your normal page delivery costs are not included.
Why can actual A/B testing bandwidth costs be lower than this estimate?
Browser caching, CDN caching, compression, and users not downloading every asset can reduce transferred data. The estimate assumes the stated extra payload is transferred on each test exposure.
Should I use KB or KiB for payload size?
Use the size reported by your performance or network tool. This calculator converts using decimal billing units, where 1 GB is 1,000,000 KB, which is common in provider pricing.
How can I reduce experiment bandwidth costs?
Keep experiment code small, load assets only when needed, compress files, reuse cached assets, and avoid sending large variant media to users who will not see it.
Does traffic allocation affect bandwidth cost?
Yes. Serving a test to 50% of eligible traffic generally creates about half the incremental transfer of serving the same payload to 100%, assuming similar user behavior.
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Assumptions and warnings
Assumptions
- Bandwidth is calculated only for the additional payload caused by the experiment, not the full page weight.
- Each visitor is assumed to generate the stated average number of eligible page views.
- The traffic allocation is assumed to remain consistent throughout the month.
- The calculation uses decimal units: 1 GB equals 1,000,000 KB.
- Your provider's bandwidth price is assumed to be constant and to exclude taxes, minimum charges, and other service fees.
Warnings
- This calculator provides an estimate only; actual CDN or hosting charges can differ because of caching, compression, regional pricing, and provider billing rules.