TL;DR
- Pick Kling 4.0 for single shots longer than 15 seconds. It runs up to 30 seconds per clip, with audio in every clip. Pick Kling 3.0 for 4K, first-and-last-frame control, or cheaper short clips. A 5-second 720p clip with sound is $0.715 on Kling 3.0 and $1.10 on Kling 4.0.
- Both run on HiAPI through the same
/v1/tasksendpoint. Open the Kling 4.0 model page and run the prompts below on each model to compare.
Kling 4.0 vs Kling 3.0 at a glance
| Kling 4.0 | Kling 3.0 | |
|---|---|---|
| Clip length | 3–30 s | 3–15 s |
| Resolution | 720p, 1080p | 720p, 1080p, 4K |
| Audio | Always on | sound toggle |
| 720p per second | $0.22 | $0.10, $0.143 with sound |
| 1080p per second | $0.33 | $0.129, $0.193 with sound |
| 5 s at 720p with audio | $1.10 | $0.715 |
| Image-to-video | One first frame | First frame, or first + last frame |
| Wait for a 5 s 720p clip in this test | About 3–4 min | About 1.5 min |
HiAPI list prices, checked October 26, 2026. Wait time is submit-to-done for the clips in this article, including queueing.
Same prompt: a steam train in the pines
An old steam train pulls slowly out of a mountain station at dawn, thick white steam billowing into low golden sunlight, pine forest on both sides, slow lateral tracking shot, cinematic depth of field, natural engine rumble and distant birdsong
| Kling 4.0 | Kling 3.0 |
|---|---|
Generate with this prompt → (Kling 4.0, 720p, 5 seconds)
Same prompt, 16:9, 720p, 5 seconds, one run each, both with audio. Kling 4.0 $1.10 (model page example); Kling 3.0 with sound $0.715.
What you can see:
- Light: Kling 4.0 puts a low, golden backlight behind the treetops. Kling 3.0 renders a pale morning mist, and the "low golden sunlight" is hard to spot.
- Camera: both track sideways. Kling 3.0 adds tree trunks sliding past in the foreground, which gives more depth layers.
- Locomotive: Kling 4.0 draws a heavy black engine; Kling 3.0 a smaller train with red wheels and brown coaches.
Same prompt: handing over a skewer at a night market
Two friends laugh at a night market food stall, one hands the other a grilled skewer, smoke and steam rising from the grill under warm string lights, handheld medium shot, sizzling grill and lively crowd chatter
| Kling 4.0 | Kling 3.0 |
|---|---|
Generate with this prompt → (Kling 4.0, 720p, 5 seconds)
Same prompt, 16:9, 720p, 5 seconds, one run each. Kling 4.0 $1.10, about 3.5 minutes; Kling 3.0 with sound $0.715, about 1.5 minutes.
What you can see:
- Action: in the Kling 4.0 clip the two face each other; she holds out the skewer and he takes it, so the hand-off plays out in full. In the Kling 3.0 clip they stand side by side, he picks skewers off the grill, and they are still in his hand at the end.
- Background: Kling 4.0 places the vendor between them with smoke rising straight up from the grill. Kling 3.0's smoke is thicker and fills the right half of the frame.
- Audio: both have an audio track. The Kling 4.0 track is louder (peak about -0.5 dB versus -4.4 dB).
Which one for which job
- 30-second product demos or long establishing shots: Kling 4.0, one clip, no stitching.
- 4K delivery: Kling 3.0 at $0.479/s.
- Transitions controlled by first and last frames: Kling 3.0 image-to-video.
- High-volume 5–10 second clips on a budget: Kling 3.0 with sound, $0.715 per 5 seconds.
- Prompts with a specific character action: run one clip on each and compare before committing.
- Silent footage for your own score: Kling 3.0 with sound off, $0.10/s at 720p.
Switching from Kling 3.0
Same POST /v1/tasks, same submit, poll and download flow. To move to 4.0:
- Set
modeltokling-4.0/text-to-videoorkling-4.0/image-to-video. - Remove
sound. Every 4.0 clip has audio, and sending the field returns a 400. - Use
720por1080pforresolution.
Full code is in the Kling 4.0 API guide; the Kling 3.0 request reference is in the Kling 3.0 API guide.
FAQ
How much more does Kling 4.0 cost than Kling 3.0?
For 5 seconds at 720p with audio, $1.10 versus $0.715, about 54% more. At 1080p, $1.65 versus $0.965, about 71% more.
Which is cheaper for a 30-second video?
Kling 3.0 caps a clip at 15 seconds, so two 720p clips with sound cost $4.29. One 30-second 720p clip on Kling 4.0 is $6.60, and you get a single continuous shot with no cut.
Will my Kling 3.0 code run on 4.0?
Yes, after three changes: the model, removing sound, and keeping resolution at 720p or 1080p.
Can I turn off audio on 4.0?
No. Every clip includes synchronized sound. For silent footage, use Kling 3.0 with sound off.
Rates and budgets are in Kling 4.0 API pricing, and more scenes are in Kling 4.0 prompts. Copy the night market prompt above and generate the Kling 4.0 version.
