Quick Verdict
- Cheapest per second
- Veo 3.1 Lite API at $0.05/s (720p)
- Best subscription value
- Depends on volume — see the table
- Biggest hidden cost
- Retries: 3 takes per clip triples the bill
- Prices verified
- Oct 2026, official sources
There is no free lunch in AI video generation — but the price tags are deliberately hard to compare. One tool bills per second, another sells you a private currency called "credits," a third bundles everything into a seat license. A $50 monthly budget means something completely different under each model.
This guide puts six mainstream tools side by side with real numbers, shows the math for two realistic jobs, and names the traps — including the "free" offers that aren't.
The price table: six tools, one view
All figures below were read directly from official pricing pages. Dates matter: prices move, so each row carries its verification date.
| Tool | Entry plan | Monthly allowance | Per-generation cost | Verified |
|---|---|---|---|---|
| Veo 3.1 (API) | No subscription — pay per second | None | Fast: $0.10/s (720p), $0.12/s (1080p), $0.30/s (4K); Standard: $0.40/s (720/1080p), $0.60/s (4K); Lite: $0.05/s (720p), $0.08/s (1080p) | 2026-10-05, ai.google.dev/gemini-api/docs/pricing |
| Runway | Standard $15/mo ($12/mo annual) | 625 credits/mo | Gen-4.5: 12 credits/sec → ~52 sec of Gen-4.5 per month | 2026-10-05, runway.com/pricing |
| Pika | Starter $10/mo ($8/mo annual) | 900 credits/mo | Seedance 2.5: 122 credits per 5s clip (720p); Wan 3.0: 33 credits per 5s clip | 2026-10-05, pika.art |
| Kling | Standard $6.99 first month, then $8.80/mo | 660 credits/mo | 4.0 per-second rates: not published (see note) | 2026-10-04, kling.ai |
| HeyGen | Creator $29/mo ($24/mo annual) | ~600 credits/mo (third-party verified) | Avatar IV/V ≈ 20 credits per finished minute | 2026-10-04, heygen.com/pricing |
| Synthesia | Starter $29/mo | 1,250 credits/mo | ≈ 100 credits per finished minute ("Estimates only") | 2026-10-04, synthesia.io/pricing |
Kling 4.0 rate gap (checked 2026-10-04): Kling publishes subscription prices and monthly credit allowances, but no per-second rate card for 4.0 generations exists on its official pages, and third-party reports confirm none has been published. Any "cost per Kling video" figure you see elsewhere is someone's estimate, not Kling's number. We exclude Kling from per-second calculations rather than invent one.
Two things jump out immediately. First, "credits" are not comparable across tools: a Runway credit buys 1/12 of a generated second; a Synthesia credit buys roughly 1/100 of a finished minute. Always convert to seconds or minutes before comparing. Second, Veo is the only tool here with honest linear pricing — no subscription, no quota, no rollover. That honesty cuts both ways, as the scenarios below show.
The "free" trap, documented
In August 2026, a Higgsfield ad for Seedance 2.0 circulated on Instagram promising "FREE" and "UNLIMITED" generation. The reel drew 3.8K likes and 210 comments — with commenters questioning the claims, calling it a scam and noting a $750 subscription behind the promise. New "unlimited free" claim posts were still appearing in early October 2026. The pattern is durable: "free" in AI video marketing usually means a free tier, not free usage.
What free tiers actually give you, per the official pages:
- Pika Free: $0/month, no monthly credits at all — you buy credit packs. No watermark, but no commercial license either.
- HeyGen Free: $0, 3 videos per month with trial access to premium features. Third parties report 720p exports with watermark; HeyGen doesn't publish the free export specs.
- Kling Free: limited daily credits (see our Kling review for the current structure).
Free tiers are fine for testing whether you like a tool. They are not a production plan, and any ad suggesting otherwise deserves the skepticism those comment sections show.
Scenario 1: a 15-second clip, 3 tries each
Nobody keeps their first generation. Two to three takes per clip is normal — and retries are where video budgets actually go. Here's the math for 15 finished seconds at 3 generations per clip, on Veo 3.1 Fast at 1080p ($0.12/s, verified 2026-10-05):
- Count the clips. Veo generates in fixed 8-second clips: ceil(15 ÷ 8) = 2 clips.
- Multiply per clip. 2 clips × 3 generations = 6 generations. The ×3 applies to each clip independently — each retry regenerates a whole clip.
- Billable seconds. 6 × 8 = 48 seconds.
- Cash. 48 × $0.12 = $5.76.
The naive estimate — 15 × $0.12 = $1.80 — underbills by more than 3×. It ignores both clip rounding and retries.
On Runway Standard, the same job burns 48 generated seconds × 12 credits = 576 credits — 92% of the 625-credit monthly allowance, for 15 seconds of finished video. You don't see a bigger bill; you see your quota evaporate. Track your kept-vs-generated ratio: below 1:2, your effective cost per finished second is double the sticker rate on any billing model.
Scenario 2: one finished minute, delivered
A client asks for one finished minute of 1080p AI video, and you generate each clip twice, keeping the better take. Veo 3.1 Fast:
- Clips: ceil(60 ÷ 8) = 8 clips; 8 × 2 generations = 16 generations; 128 billable seconds.
- Cost: 128 × $0.12 = $15.36.
- At 3 takes per clip: 192 billable seconds = $23.04.
Drop to 720p ($0.10/s) and the 3-takes minute costs $19.20 — a 17% saving for a resolution difference most viewers won't notice on a phone. Push to 4K ($0.30/s) and it's $57.60. Retries multiply whatever rate you pick, so choosing resolution before you start retrying is one of the cheapest decisions in the whole workflow.
Freelancer quoting rule derived from the above: quote = ceil(finished ÷ clip_length) × takes_per_clip × clip_length × rate, then add your margin. If any input is a guess, mark the quote as an estimate.
Which billing model fits which volume
- Steady, predictable, under-quota usage → subscription. The flat fee wins when your per-second alternative would cost more. Example: if you need 200 generated seconds of Gen-4.5 a month, Veo Fast 1080p would charge 200 × $0.12 = $24 — but 200 seconds needs 2,400 Runway credits, far beyond Standard's 625, so neither plan fits cleanly; that's exactly why you must run your own volume through both models instead of trusting the sticker price.
- Spiky or experimental usage → pay-per-second. Veo's API costs $0 in quiet months. Subscriptions charge the full fee whether you generate 10 seconds or 600.
- Talking-head / training video at volume → avatar subscriptions. Synthesia Starter's $29 covers roughly 12 finished minutes a month at its estimated rate — but it makes AI presenters, not cinematic clips. Compare within the job type, not across them.
What we couldn't verify
- Kling 4.0 per-second/credit rates: not published as of 2026-10-04. Excluded from all calculations.
- Runway top-up unit price: 1,000-credit minimum confirmed; per-credit price not on the pricing page.
- HeyGen's ~600 Creator credits: third-party verified; HeyGen doesn't publish the figure directly. Avatar IV/V ≈ 20 credits/min likewise third-party.
- Synthesia actual consumption: officially "Estimates only."
- InVideo's credit-to-second conversion for Seedance models varies by model and tier; check the current InVideo review before budgeting.
Prices change. Every figure above carries its verification date — re-check the official pages before spending.
Frequently asked questions
Which AI video tool is cheapest per second of video?
By published rates, Veo 3.1 Lite API at $0.05/s (720p), verified 2026-10-05. But per-second price alone doesn't determine your bill — clip rounding and retries multiply it, as the scenarios above show.
Are Kling 4.0 per-video costs published?
No. As of 2026-10-04, Kling publishes subscription prices and monthly credit allowances but no per-second rate card for 4.0 generations. Any per-video Kling figure you see elsewhere is an estimate, not an official number.
How many retries should I budget for?
Two to three generations per clip is normal. Budget 3 takes per clip and you'll rarely be surprised; budget 1 and you almost certainly will be.
Do unused subscription credits roll over?
On the tools covered here, no — monthly credits expire at reset (Kling, Runway, Pika). That's the core subscription trap: you pay the full fee in months you barely generate.