A/B Testing Token Usage (Per-User) Calculator
Estimate and compare the average token usage per user for two A/B test variants based on prompt, response and usage patterns.
Overview
This A/B testing token usage calculator estimates how many model tokens each user consumes in Variant A and Variant B. Enter average input and output tokens per request, expected requests per user and the test traffic split to see the blended usage per participant.
How it works
For each variant, the calculator adds average input and output tokens per request, then multiplies that total by average requests per user. It applies your traffic split to the two per-user totals to calculate the average usage across all test participants. The percentage comparison shows how Variant A differs from Variant B, using Variant B as the baseline.
How to use this calculator
- 1Enter the percentage of users assigned to Variant A.
- 2Add the average number of requests made by each test user.
- 3Enter average input and output tokens for Variant A.
- 4Enter average input and output tokens for Variant B.
- 5Review the per-user totals and the traffic-weighted average.
Example Calculation
Variant A traffic share
50%
Average requests per user
10
Variant A input tokens per request
800
Variant A output tokens per request
300
Variant B input tokens per request
1000
Variant B output tokens per request
400
Average tokens per test user
12,500 tokens
Variant A uses 11,000 tokens per user and Variant B uses 14,000 tokens per user. With an even split, the test averages 12,500 tokens per participating user.
Frequently asked questions
What counts as input tokens in an A/B test?
Input tokens generally include system instructions, user prompts, conversation history, retrieved context and tool-related content sent to the model.
Why calculate token usage per user instead of per request?
Per-user usage accounts for how often people use each variant, making it easier to compare the expected impact of a test on a participant basis.
Does a 50/50 A/B test always have the same average token usage?
No. The average depends on each variant's tokens per request and how many requests users make. A 50/50 split simply weights both variants equally.
What does a negative A minus B token result mean?
It means Variant A uses fewer tokens per user than Variant B by the displayed amount.
Does this calculator estimate API cost?
No. It estimates token volume. To estimate cost, apply the relevant provider prices separately to input, output, cached or other billed token categories.
Should I use averages or maximum token counts?
Use observed averages for planning typical experiment usage. Review upper-percentile or maximum usage separately when you also need capacity or budget-risk scenarios.
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Assumptions and warnings
Assumptions
- Input and output token values are averages that represent typical requests for each variant.
- Each participating user makes the entered average number of requests during the selected measurement period.
- Traffic allocation is the only weighting factor; user behavior is otherwise assumed to be comparable across variants.
- The estimate includes model input and output tokens but excludes provider-specific billing rules, cached-token pricing and non-token charges.
Warnings
- Token counts and billing categories can differ by model provider, model version and API configuration.
- This calculator estimates usage volume, not monetary cost; check your provider's current pricing and token accounting documentation.