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Find the real field size behind your test.
Map assigned variants, markets, and mutually exclusive cells before estimating invitations or cost.
Calculation: variants × markets × mutually exclusive segment cells × usable completes per cell. The field target divides usable completes by 1 minus the expected exclusion rate. Invitations divide that target by screener-start rate × incidence × eligible completion rate. Cost multiplies the field target by your entered cost per complete.
Overlapping reporting cuts do not automatically multiply the design. This is a field-size and cost planner—not a statistical power or minimum-detectable-effect calculator. Calculator inputs remain in page memory and are not sent or written to site storage by this application.
Use cells deliberately
If the U.S. and Canada require separate conclusions, those are separate market cells. Mutually exclusive groups also multiply the design when each requires its own usable base. Overlapping cuts—such as age and device within the same respondents—should not both be entered as separate cell multipliers.
Read the field target and cost together
The field target divides usable completions by the expected share remaining after quality exclusions and rounds up. Invitation counts then divide that target by the screener-start, incidence, and completion rates. These are planning assumptions, not observed response rates or guaranteed delivery.
Indicative cost multiplies all field completions by the entered price, including completions later excluded for quality. It omits recruitment, screening, translations, coding, taxes, and platform fees. Confirm what your provider actually bills before budgeting.
Reproduce the fictional 800-completion decision-brief example: its stated assumptions produce 910 field completions, 4,375 invitations, and US$2,275 indicative cost. The walkthrough specifies every input and explains why that operational base is not a power recommendation.
Pre-specify before fielding
Write the primary comparison, exclusion rules, minimum cell sizes, weighting approach, and stopping rule before results are visible. Confirm statistical power separately using the intended outcome, expected variance, test, allocation, and minimum effect worth detecting.