Effort: Low
What to notice
Keep the billing period and actual total visible alongside small equivalent amounts.
Where it fits
- Fits
- People comparing recurring fees
- Use it when
- Period equivalents help comparison.
- Avoid it when
- Usage-based pricing makes simple conversion misleading.
How to build it
- Establish the actual billing period and mandatory-cost inclusive source amount.
- State conversion days and rounding, using one source value.
- Repeat the actual charge and contract term before commitment.
Measure
- Main metric
- Correct recall of the actual charge
- Guardrail
- Misunderstanding or cancellation caused by small-unit display
- How to measure
- Measure charge comprehension alongside completion; more clicks on a small number alone are not success.
When it backfires
Do not imply monthly billing when the monthly value is an annual-contract equivalent.
Alternatives
Theory behind it
Mental accounting
People evaluate money within budgets and transactions as well as in one overall total.
Theoretical model
Framing effect
Equivalent facts or options can produce different judgments when presented in different frames.
Limited evidence
Evidence limits: An editorial application of mental accounting, requiring comprehension tests rather than assuming a conversion gain.