A three-second clip still buys the first five seconds
Base-plus-marginal models sell an indivisible 5s block then a per-second add-on, so 3s costs the same as 5s and 10s is base plus five extras.
Base-plus-marginal models sell an indivisible 5s block then a per-second add-on, so 3s costs the same as 5s and 10s is base plus five extras.
That is the formula on /cost/video-clip-longer-than-5-seconds: credits = base_first_5s + rate_per_extra_second × (seconds − 5), with (seconds − 5) clamped at zero. Anything at or under five seconds is the full base. There is no prorate. Under linear per-second billing, three seconds costs three-fifths of five. Here it costs the same as five. A short clip on this family is pure waste.
The block is indivisible
Kling O3 Pro Image to Video is the cost page's anchor for this shape. First 5 s: 70 credits. Each extra second: 14. Published range 70–210. Supported durations include 3s through 15s. The picker will let you ask for three seconds. The meter will still charge 70.
Five seconds is 70. Ten seconds is 70 + 14 × (10 − 5) = 140. Fifteen seconds is 70 + 14 × 10 = 210, which is also the published ceiling. Three seconds is 70. Four seconds is 70. The floor of the published range is the base. A clip cannot cost less than one block however short you make it.
The blended cost inside the opening block is 70 / 5 = 14 credits a second — the same number as the marginal rate on this row. That is why a single 15 s clip and three separate 5 s clips both land at 210 here. The trap is not "15 versus 3×5." The trap is 3 s: you paid for five seconds of media and received three.
Twenty-five catalog models bill base_plus_per_second. Bases currently run from 21 credits on Kling 2.5 Turbo to 210 on Kling Video V3 4K text-to-video. The ratio of extra to base is not constant across the family. Read the model page. Do not steal O3 Pro's 14 and apply it to a different row.
The arithmetic on Kling O3 Pro
| Clip length | Charge | Effective per second |
|---|---|---|
| 3 s | 70 (base only) | 23.3 |
| 5 s | 70 (base only) | 14 |
| 6 s | 70 + 14 | 14 |
| 10 s | 70 + 14 × 5 = 140 | 14 |
| 15 s | 70 + 14 × 10 = 210 | 14 |
Three seconds is the worst value on the table: same 70 as five, at nearly double the effective rate. If the beat is a hook, take the full block. If you need eight seconds, check what ten costs before you cut it down — on this row eight is 70 + 14 × 3 = 112, ten is 140.
Splitting one long take into several shorts is expensive when any of those shorts fall under five seconds. Five separate 3 s clips: 5 × 70 = 350. One 15 s clip: 210. Two 3 s takes: 140. One 6 s take: 84. Always take the whole block you already paid for.
A Monthly plan's 580 credits is floor(580 / 70) = 8 five-second clips on O3 Pro, or floor(580 / 140) = 4 ten-second ones. Same plan, half as many files if every clip spends the marginal five.
Three seconds of media is still five seconds of bill
O3 Pro is image-to-video: requires_image is true. You already brought a still. The duration picker is the second decision, and it is the one this formula punishes. Asking for 3 s because "the ad is a glance" does not change the entry price. Use the glance inside a 5 s hold. Trim in the editor after if the platform cap is 3 s. The generate still bought five.
This is the only catalogue formula with an entry price in it, and it inverts the usual advice about keeping clips short. Linear per-second rows (lipsync, some extends) really do get cheaper as you cut. Tiered duration rounds the other way: a seventh second can jump a whole stair. Do not mix the three shapes. The cost hub exists so you can see which meter you are on before you dispatch.
O3 Pro also lists camera control, reasoning-enhanced generation, and native audio. None of those are terms in the duration formula. Audio on this row is not a second rate. Duration is the meter. Extra seconds are the cheap part of the page. The opening block is the floor.
What the base price does not cover
The 70 does not buy an extend of an already-rendered clip. Extends are a different job, billed as a flat per-second rate with no base — that is why a long extend can quietly become the largest line in an account.
The 70 does not buy a tiered model. Rows that sell duration in whole units (6 s / 10 s stairs) have their own page. Rounding there is a staircase, not a clamp-at-zero.
The 70 does not buy captions, a voiceover, or a final editor export. Those are other meters. A finished ad is four of them added together; this page is only the entry block.
/cost is the formula index. This scenario is "why a three-second clip is the worst value on the page." If the job is actually 3 s of picture, generate 5 s and cut. Do not ask the model to prorate a block it does not sell.
FAQ
Does a three-second clip cost less than a five-second one on this family?
No. The first five seconds are a single indivisible block. On Kling O3 Pro both durations are 70 credits. The picker may offer 3 s. The bill does not shrink.
Is the sixth second cheaper than the first five?
On O3 Pro the extra second is 14 credits, which matches the blended 70/5 inside the block. Across the family the ratio is not constant. After five seconds you are on the marginal meter; under five you are not.
Is one long clip cheaper than several shorts?
When any of the shorts fall under five seconds, yes, often by a lot: five 3 s clips are 350 credits on O3 Pro, one 15 s clip is 210. Three full 5 s clips equal one 15 s clip on this particular row because extra happens to be 14.
Why does the catalogue show a range instead of one price?
The total depends on duration. The floor is the base. The ceiling is the base plus extras out to the model's longest clip — 210 at 15 s on O3 Pro.