Kling 4.0 vs Veo 3.1: what each costs per second and per usable clip

Price per second and per usable clip, 720p with audio

All rows are first-party list prices. The "attempt" column is the price of one 8 s generation. The usable-clip column divides it by a 50% keeper rate, which is an assumption (you keep one clip in two), not a measured figure for any model. Change it in the calculator.

Kling 4.0 audio is native with no toggle, per the Runway API docs. Kling 4.0 Flash, the cheaper 4.0 tier, is $0.0923/s at 720p; Kling does not state its audio behaviour on the pricing page. The full per-row detail, with sources, is in the price table.

Resolution and audio change the gap

• Veo 3.1 Standard costs the same at 720p and 1080p ($0.40/s with audio, $0.20/s without). 4K with audio is $0.60/s.
• Veo 3.1 Fast rises from $0.10/s at 720p to $0.12/s at 1080p and $0.30/s at 4K. Silent output is cheaper: $0.08/s at 720p.
• Kling 4.0 goes from $0.154/s at 720p to $0.231/s at 1080p. A 4.0 request that includes an input video is billed on input plus output seconds, so it is not a flat per-second price.
• Kling 3.0 audio adds 50% (720p $0.084/s silent, $0.126/s with audio). It lists a 4K rate of $0.42/s; no 4K rate is listed for 4.0.

For the rest of the resolution and audio ladder, see resolution and audio pricing.

The same model costs different amounts on resellers

Veo 3.1 Fast is $0.15/s on fal.ai and Replicate, against $0.10/s on Vertex at 720p. Veo 3.1 Standard is the same price on fal.ai as on Vertex ($0.40/s). Kling 3.0 on fal.ai matches Kling's own rate. Kling 4.0 has no printed fal.ai price on the page that was read.

Other resellers add Kling 4.0 and Veo 3.1 at their own rates:

• Runway API lists Kling 4.0 at 15.7 credits per second ($0.01 per credit) and has it at 20% off through 2026-11-30, and lists Veo 3.1 at 40 credits per second with audio.
• Luma Dream Machine Plus lists Kling 4.0 at 53 credits per second at 720p and Veo 3.1 at 140 credits per second. At the Plus credit value that is about $0.159 and $0.42 per second (derived).

The reseller comparison, including when a premium is worth paying, is in fal.ai vs Replicate vs direct API, and the Runway side in Kling vs Runway price.

How the keeper rate changes the ranking

A model that costs more per second only wins if you keep more of what it makes. Published keeper rates do not exist for these models, so the useful question is how much better one model would need to be. Ratios of list price at 720p with audio:

• Kling 4.0 costs about 1.5 times Veo 3.1 Fast per second. Kling 4.0 only comes out cheaper per usable clip if you keep roughly 1.5 times as many of its generations.
• Veo 3.1 Standard costs about 2.6 times Kling 4.0. At the same keeper rate Kling 4.0 is cheaper. Standard only catches up if you keep about 2.6 times as many of its clips.
• Veo 3.1 Lite is half of Fast. Fast needs double the keeper rate of Lite to break even.

If you have used both models on your own prompts, plug your own rates into the calculator.

Limits and buying terms

• Clip length: Veo 3.1 on Vertex generates 4, 6 or 8 s clips, and reference-image mode is 8 s only. Kling 3.0 is listed at up to 15 s on a Replicate page; no maximum for 4.0 was found on Kling's pricing page. See length limits.
• How you pay: Vertex bills per generated second as used. Kling's API is sold as prepaid packages: the flagship (4.0 and 4.0 Flash) packs start at $500, general packs at $700, both valid for 180 days with no rollover. A $9 trial pack exists on first purchase.
• Region and concurrency: the Veo 3.1 model reference lists us-central1 only. Kling's flagship packs list 20 concurrent tasks.
• Watermarks and terms: Veo outputs carry SynthID, and fal.ai states it cannot be disabled. Commercial-use wording for Kling and Vertex was not stated on the pricing pages read, so check each provider's terms before client work. See commercial use rules.
• Sora: queries comparing Sora 2 with Veo 3.1 are out of date. OpenAI shut the Sora 2 API on 2026-09-24. See Sora API alternatives.