Seedance 2.5 Extend is billed per second of video at the video-input rate for the resolution you choose. An extension reads your source clip and writes only the new footage (the output does not contain the original clip), and both are billed: the seconds of new footage plus the seconds of source the model reads. The source portion is never billed at less than two-thirds of the new footage, rounded up to the next whole second.
billed seconds = new footage + max(source clip length, ⅔ x new footage, rounded up)
cost ≈ rate x billed seconds
Extra reference_videos add their full length to the source portion.
Per-Second Rates (16:9)
| Resolution | Rate |
|---|---|
| 480p | $0.0637/s |
| 720p | $0.1429/s |
| 1080p | $0.3519/s |
The output takes the source's aspect ratio automatically. Other ratios price within about 1% of 16:9 at the same resolution, so the clip's shape is not a cost lever; resolution and the length of the new footage are.
Quick Cost Examples
| Resolution | Source clip | New footage (duration) | Billed seconds | Cost |
|---|---|---|---|---|
| 480p | 5 s | 4 s | 9 | $0.57 |
| 480p | 5 s | 6 s (-1, model's choice) | 11 | $0.70 |
| 720p | 5 s | 5 s | 10 | $1.43 |
| 720p | 5 s | 6 s (-1, model's choice) | 11 | $1.57 |
| 720p | 5 s | 10 s | 15 | $2.14 |
| 720p | 30 s | 5 s | 35 | $5.00 |
| 720p | 2 s | 30 s | 50 (minimum applies) | $7.15 |
| 1080p | 5 s | 5 s | 10 | $3.52 |
Credit Holds vs. Your Final Charge
On request, Segmind holds credits sized for a long source plus the footage you asked for at your resolution, which can be well above the final price. On completion the hold settles at the actual cost and the difference returns to your balance right away. Reconcile against your balance after the request settles. Failed generations are not billed.
Important Notes
- The source clip is billed on top of the new footage: extending a 5 s clip by 4 s at 480p is 9 billed seconds, not 4.
durationis the new footage only: the output starts on the source's last frame (or ends on its first frame for a backward extension) and does not include the original clip. Leave it at-1and the model picks about 6 s for a 5 s clip.- Reference images and audio are free: they do not add billable seconds. Extra reference videos do, at their full length.
- Audio is free: generating a soundtrack does not change the price.
- Resolution is the main lever: 480p → 720p is about 2.2x per second, 720p → 1080p about 2.5x.
- Rates are close estimates: the final charge is computed from the exact amount of video processed and can differ from these figures by 1–2%.
Cost Optimization Tips
- Send the shortest source that carries the scene: the model only needs the end (or start) of the clip to continue it, and every source second is billed.
- Set
durationto what the shot needs: the new footage is the part you control, and the source minimum rises with it. - Iterate at 480p, deliver at 720p or 1080p: the same 5 s + 4 s extension costs $0.57 at 480p and $3.17 at 1080p.
- Fix the seed: lock a seed and refine the prompt rather than re-rolling.