Grok Imagine Video 1.5: xAI direct vs Runway credits for 30 clips

Thirty six-second clips is 180 seconds of video. On xAI's own API, Grok Imagine Video 1.5 at $0.080 per second is $14.40; the same model through Runway at 720p is 16 credits per second, $0.16 at one cent per credit, so $28.80. Runway charges twice the xAI per-second price at 720p.

The xAI models page (read 2026-10-04) lists video 1.5 at $0.080 per second, base at $0.050 and 1.5-lite at $0.020. The Runway pricing guide (read 2026-10-04) lists grok_imagine_1_5 at 10, 16 and 29 credits per second for 480p, 720p and 1080p.

What the credit math says

Runway credits are $0.01 each, so 16 credits is $0.16. Against xAI's $0.080 that is 2.0x at 720p. The xAI page lists one per-second price for video 1.5 and does not split it by resolution in the table I read, so the 1080p gap is not a clean comparison; treat the 480p and 720p rows as the like-for-like ones.

The other side of the trade is what you get with the price. Runway bundles its own workspace, credits and the other models in its catalog; xAI's API is the model vendor directly.

Where Sume sits

Sume does not list a Grok video price in its catalog, so there is no Sume row for this model. For scale only, Sume's Gemini Omni Flash 1.1 is billed at provider list x 1.25 per output second: $0.10 list becomes $0.125 per second at 720p, so 180 seconds is 180 x $0.125 = $22.50. That is a different model with its own look, not a substitute you can swap in blind.

• Sume reserves the amount at submit and captures actual usage; a failed or cancelled generation is not billed.
• Grok Imagine Video 1.5 on xAI direct is the cheapest 1.5 route in the table, at $14.40.

Steps to choose

• Decide the resolution first; Runway's price roughly triples from 480p to 1080p (10 to 29 credits).
• Multiply total seconds by the per-second price, not clip count by a guessed price.
• Run three test clips on the cheapest route before committing 30; if you need the lite tier, 180 seconds is $3.60 and may be enough for drafts.
• Keep retries in the budget. Re-rolling one clip in five adds 6 x $0.080 = $0.48 per retry on xAI.

Scaling the batch

A campaign of 300 six-second clips is 1,800 seconds. On xAI at $0.080 that is $144; on Runway at 720p it is 1,800 x $0.16 = $288; on the xAI lite tier it is 1,800 x $0.020 = $36. The Runway premium at that size is $144, as much as the whole xAI bill.

Caveats

Prices come from the vendors' pages on 2026-10-04 and promotions change quickly. Check that the xAI resolution you will request matches the listed price before you scale. This page is about cost per second, not quality; a cheaper tier that needs more retries can cost more per usable clip.