1. Generation credit usage
For a per-second model: credits per output = selected duration in seconds × official credits per second. For a per-generation model: use the official model price for the chosen duration and eligible account tier. A request may return multiple chargeable outputs.
2. Retries, expected value and whole-generation budgets
Expected attempts = finished outputs × (1 + extra attempts per finished output). Expected credits = expected attempts × credits per output. Since you cannot purchase a fractional generation, budget credits = ceiling(expected attempts) × credits per output. This is a planning heuristic, not a probability distribution or a billing guarantee.
3. Monthly plans and minimum refills
Shortfall credits = max(0, estimated credit demand − credits in plan). For Runway web plans, purchased credits are sold starting at 1,000 credits (US$10); total top-up spending is rounded up to whole 1,000-credit purchases at the listed reference rate. The tool does not assume you can buy exactly 75 credits for US$0.75.
4. Account ecosystems remain separate
Google Flow credits are not Runway credits. Runway Dev API credits are separate from Runway web subscription credits. Google Flow's free daily allotment is excluded from monthly pool comparisons because daily limits are not interchangeable with a monthly balance.
5. Dollar cost is not universally tied to credits
Runway API documentation states a developer credit purchase price of US$0.01 per credit. That does not mean a Runway web subscriber's effective cost is always US$0.01 for every included credit. On some tools we allow you to enter your own effective credit cost for internal planning.
6. Production profitability
ROI = ((revenue − expenses) ÷ expenses) × 100. Revenue estimates are provided by the user. All cash costs should be included once, including subscriptions, top-ups, editing and distribution.
7. Quality and update policy
Pricing references are checked at publication and should be refreshed regularly. We link to first-party documentation and note missing data rather than silently filling unknown values. The site is informational, independently operated and does not claim affiliation with the named providers.