A/B Testing Bandwidth Cost (Annual) Calculator
Estimate the annual data-transfer cost of an A/B test from traffic volume, page weight, test allocation, variant split and CDN pricing.
Overview
Use this A/B testing bandwidth cost calculator to estimate the yearly data-transfer cost of an experiment. Enter your monthly visitor volume, typical pages per visitor, test traffic allocation, control and variant page weights, traffic split, and effective CDN price per GB.
How it works
The calculator estimates monthly page views by multiplying visitors by pages per visitor, then applies the percentage of traffic included in the test. It divides those test page views between control and variant according to the selected traffic split. Each group is multiplied by its page weight, converted from KB to decimal GB, and annualized over 12 months. The annual bandwidth amount is then multiplied by your CDN cost per GB. The incremental result compares this mixed control-and-variant cost with a control-only baseline for the same experiment traffic.
How to use this calculator
- 1Enter your average monthly visitor count.
- 2Add the average number of pages viewed per visitor.
- 3Set the percentage of traffic participating in the experiment.
- 4Enter the transferred page weight for the control and variant.
- 5Choose the share of test traffic sent to the variant.
- 6Add your effective CDN or data-transfer price per GB and review the annual estimate.
Example Calculation
Monthly visitors
100000
Pages per visitor
3
Traffic included in test
50%
Control page weight
1500
Variant page weight
1700
Variant traffic split
50%
CDN cost per GB
$0
Annual A/B test bandwidth cost
$230.40
With 100,000 monthly visitors viewing 3 pages each, a 50% test allocation, and a 50/50 split, the experiment transfers about 288 GB per year. At $0.08 per GB, the estimated annual A/B test bandwidth cost is $23.04, which is about $1.44 more than a control-only baseline.
Frequently asked questions
What is included in A/B testing bandwidth cost?
This estimate includes data transferred when test visitors receive control or variant pages. It uses the page weights and CDN price you enter.
Does an A/B test always increase bandwidth costs?
Not necessarily. If the variant has the same page weight as the control, its page-delivery bandwidth cost is the same for the tested traffic. A heavier or lighter variant changes the cost.
Why does the calculator use pages per visitor?
Visitors may load more than one page during a visit. Pages per visitor converts visitor traffic into an estimated number of page views that can generate data transfer.
What CDN rate should I enter?
Use your effective marginal cost per GB where possible. If your provider has tiered or regional prices, a blended average rate is a practical estimate.
Does this calculator include A/B testing platform fees?
No. It estimates page-delivery bandwidth charges only. Subscription fees, event tracking, API requests, and other platform charges should be assessed separately.
How can I reduce A/B test bandwidth use?
Keep variants close to the control's page weight, optimize images and scripts, use caching where appropriate, and avoid loading assets that are not needed for the experiment.
Explore Related Calculators
Assumptions and warnings
Assumptions
- Monthly visitors, pages per visitor, and experiment allocation remain consistent throughout the year.
- One GB is treated as 1,000,000 KB, which is commonly used for decimal data-transfer billing.
- Page weights represent the average data transferred on each relevant page view.
- The CDN cost per GB is applied as a single effective rate and does not model tiered pricing, included allowances, or regional rates.
- The incremental cost compares the experiment mix with serving the control page to all traffic included in the test.
Warnings
- This calculator provides a planning estimate only; actual CDN and bandwidth charges can vary by provider, region, cache performance, and pricing tier.
- A/B testing tools may add script, analytics, API, image, or cache-related traffic that is not included unless it is reflected in your page-weight inputs.