How long a credit stays spendable
Credit validity is how long a credit remains spendable after it arrives. Where the window is short the published rate is a floor a buyer reaches only by consuming everything; where it is long, a balance behaves like a prepayment. As of 2026-09-12.
| Channel | What is published | Read from |
|---|---|---|
| HeyGen | Monthly subscribers keep credits one further month; annual credits pool to renewal | The pricing page |
| invideo AI | Unused credits do not roll over to the next month | The pricing page |
| Kling AI | Developer packages valid 180 days, with no rollover and no extension | The developer price page |
| Magnific | Rollover with no monthly reset, and credits valid one year | The pricing page |
| Runway | Two plans reset within 24 hours of the billing date; one carries a month; purchases never expire | The plans page |
Inclusion rule. Channels stating how long credits last on a page a buyer can open. A channel raising the question without answering it is recorded as unanswered rather than given a row here. Order. Alphabetical by channel name.
1A window turns a discount into a bet
Buying a larger package lowers the unit price and puts a deadline on realising the saving. Dividing a package by its validity gives the daily output the discount assumes, and a schedule that cannot sustain it makes the smaller package the cheaper purchase.
2Purchased and granted credits usually behave differently
Where both exist, one often persists and the other lapses, and the order they are spent in decides how much is wasted. Where a page does not state the order, assume the perishable pot goes first and plan the month around it.
3A long window removes the utilisation problem entirely
Credits valid a year with no monthly reset mean the published figure is the figure. That is the opposite of the common shape here, where an advertised rate is a floor a buyer reaches only by consuming the whole quota.
4Answering by billing cycle is rarer than answering by tier
One channel above varies the answer by how often the card is charged rather than by which plan was bought, which turns an annual discount into two discounts: the lower monthly figure, and a year of allowances pooling instead of expiring twelve times.
5Validity is a discount or a penalty depending on the calendar
Long-lived credits reward buying in bulk; monthly expiry punishes an uneven schedule. A season shot in bursts and one generated steadily pay different effective rates on identical published figures, and the difference is knowable before anything is bought.
Working it out needs a production calendar rather than a price list, which is why it is almost never done. An hour with the calendar is worth more than a day spent comparing headline rates.
6Pages these figures were read from
A definition entry: what the term means, and the figures vendors put in public about it, each figure read on 2026-09-12. Related: Output unit, Clip ceiling.
7The production behind the price
Price aside, what goes into the seconds behind “Credit validity” is described in SceneMixer's guides:
They are declared once in the segment header — who they are, where, what they are doing — and stay consistent across that scene.
SceneMixer, AI Multi-Character Scene Generator — “How do background extras work?” (read 2026-10-13)
The second trim replaces the first trimmed version; the generated clip stays in Version History.
SceneMixer, Trim a Clip: Cut the Start or the End Without Regenerating — “Can I trim the same clip twice?” (read 2026-10-13)