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CDN Traffic Unit Cost Estimator

The CDN Traffic Unit Cost Estimator calculates an effective cost per unit of delivered traffic by dividing a period’s CDN-related spend by outbound traffic volume. The default presentation uses terabytes as the traffic unit and combines delivery, request, and other CDN charges into one all-in cost before normalization.

This metric is useful for tracking delivery economics as traffic changes, comparing contract scenarios on a common basis, or translating a complex invoice into a simpler planning number. Separating request and other charges also reveals how much of the total cost comes from items that do not scale directly with transferred bytes. The estimator does not assume a particular provider, region, cache tier, or request pricing schedule. For meaningful trend comparisons, use costs and traffic from the same period and keep the traffic unit and included cost categories consistent from one calculation to the next.

CDN cost and traffic

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TB
Result
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Effective cost per TB
Total CDN cost—
Delivery cost share—
Non-delivery charges—
Delivered traffic—

1. Choose one billing period
Use traffic and cost figures covering the same month or reporting interval.

2. Enter delivery charges
Add the portion of CDN cost primarily associated with data delivered to users.

3. Add request and other charges
Include HTTP request charges and other CDN-specific fees you want in the blended rate.

4. Enter delivered traffic
Provide the amount delivered to users in TB for the same period.

5. Review the blended unit cost
Use cost per TB for trend or scenario comparisons, keeping the included cost categories consistent.

Formula:
Total CDN Cost = Delivery Cost + Request Cost + Other CDN Charges
Traffic Unit Cost = Total CDN Cost ÷ Delivered Traffic

Delivered Traffic is entered in TB, so the main result is shown as cost per TB. Delivery Cost Share equals Delivery Cost divided by Total CDN Cost. The metric is an effective blended rate; it does not reproduce tiered regional rates, cache-fill traffic, minimum charges, or provider-specific billing conversions.

What the result means

The main result is the all-in CDN spend for the period divided by the amount of traffic delivered in TB.

For comparisons, use the same definition of delivered traffic and the same included cost categories in every period.

Given: $4,200 delivery cost, $450 request charges, $150 other CDN charges, and 240 TB delivered.

Calculation: Total CDN cost = $4,200 + $450 + $150 = $4,800. Unit cost = $4,800 ÷ 240 = $20 per TB. Delivery share = $4,200 ÷ $4,800 × 100 = 87.5%.

Result: The effective all-in CDN cost is $20 per delivered TB for the selected period.

Should cache-fill traffic be included?

Use the traffic figure that matches the cost you are normalizing. If origin-to-CDN transfer is billed separately and included in Other CDN charges, document whether its traffic is also part of your denominator.

Can I use GB instead of TB?

The calculator is labeled in TB. Convert your delivered traffic to TB first so the displayed cost-per-TB result remains correct.

Why include request charges in a traffic unit cost?

Including them produces an all-in blended delivery rate. The separate non-delivery figure helps you see how much cost comes from charges that are not purely byte-based.

Can this rate be compared with a provider’s published per-GB price?

Only after aligning units and included charges. Published rates may exclude requests, regional variations, taxes, commitments, or other invoice components included here.

What if delivered traffic is zero?

The calculator requires a traffic value greater than zero because unit cost cannot be computed with a zero denominator.