How AI video generator credits work, and what a usable 30-second film really costs

AI video tools rarely tell you what a video costs. They sell credits, list how many credits each model burns per few seconds, and leave the arithmetic to you, along with the small print about which credits expire and which don't. For an architecture studio that wants one 30-second film per project, that makes comparing tools harder than it should be. This guide explains how AI video generator credits work, using the current pricing pages of Runway and Luma as examples, then works out what a usable 30-second film costs in credits, with retakes, and compares that with a flat price per video.

Key takeaways

• A credit is a vendor's own unit; each generation costs a set number of credits that depends on the model, the clip length and the resolution.
• Resolution can multiply the cost: on Luma's Ray3.2, a 5-second 1080p clip costs four times the 720p one, as of October 2026.
• Monthly plan credits usually expire at renewal, while purchased top-ups last longer, so your real price per credit depends on how much of the plan you use.
• A clip that renders but warps the building is still a spent generation, so budget credits for retakes, not just for 30 seconds of output.
• A flat per-video price swaps that arithmetic for a fixed number, at the cost of the per-shot control a credit tool gives you.

How AI video generator credits work

An AI video generator credit is an internal unit you spend on each generation, and the number a clip costs depends on the model, its duration and its resolution. You get credits from a monthly plan, which usually resets at renewal, or from top-up packs that last longer. What a video really costs is the credits for every usable second, plus every retake, multiplied by what you paid per credit, including the credits that expired unused.

Runway's pricing page puts it plainly: "Credits are the unit you spend to generate images, video, and audio on Runway. Each model uses a set number of credits per generation depending on the model, duration, and resolution" (Runway pricing, as of October 2026). Luma's pricing works the same way. The credit itself has no fixed dollar value; its price depends on which plan you bought and how much of it you use.

The four things that set a clip's credit cost

The model

Newer and larger models cost more per second, and many platforms now host other companies' models alongside their own at different rates. As of October 2026, Runway lists its own Gen-4.5 at 60 credits per 5 seconds, Kling 4.0 at 1080p at 118 credits per 5 seconds (89 with a discount listed until November 30), Aleph 2.0 at 140 credits per 5 seconds and Seedance 2.0 Pro at 1080p at 160 credits per 4 seconds (Runway pricing).

Duration

Credits are quoted per clip length, and the rate isn't always linear. On Luma's pricing page, a Ray3.2 image-to-video clip at 720p costs 100 credits for 5 seconds and 300 for 10 seconds; at 1080p, 400 and 1,200 (Luma pricing, as of October 2026). Two 5-second clips cost less than one 10-second clip there, which matters if you're cutting short scenes anyway. Single 30-second generations are a different trade-off again (what 30-second AI clips change).

Resolution

Resolution is often the biggest multiplier. The same Ray3.2 5-second clip costs 100 credits at 720p and 400 at 1080p. Luma lists Seedance 2.5 at 78 credits per second at 720p and 191 at 1080p.

Extras

HDR, longer outputs, audio and upscaling are often priced separately; Luma's credit guide, published December 2025, lists separate rates for HDR output (Luma credit system). Check whether the output you need, such as a 1080 × 1920 vertical file, is included at the rate you're looking at.

Monthly credits, top-ups and expiry

How credits expire changes what they really cost.

Runway. As of October 2026, Standard costs USD 15 a month (USD 12 a month billed annually) for 625 credits, Pro USD 35 (USD 28 annually) for 2,250, and Max USD 95 (USD 76 annually) for 9,500. Monthly credits don't roll over on Standard and Pro; on Max, "up to one month of unused credits rolls over." Purchased credits never expire, with a minimum purchase of 1,000 credits. The free plan gives 125 credits once (Runway pricing).

Luma. As of October 2026, Plus costs USD 30 a month (USD 25 billed yearly) for 10,000 credits, Pro USD 90 (USD 75) for 40,000, and Ultra USD 300 (USD 250) for 150,000, all with commercial use (Luma pricing). Luma's credit guide says monthly credits "do not roll over," while top-up credits are "valid for 12 months" and are "automatically used after monthly credits" (Luma credit system).

The practical effect: a plan's price per credit is only true if you use every credit. If you make one film a month on Runway Standard and it takes 360 credits, you've paid USD 15 for that film, not the USD 8.64 the credits are nominally worth; the rest expired. Top-ups that don't expire, or that last a year, suit occasional use better than a plan you barely touch.

Failed generations and retakes

Neither pricing page I read states whether a generation that errors out is refunded, as of October 2026; look for that in the vendor's help center before you rely on it. What is clear from how credits are defined is that a generation that completes is charged, whether or not you like the result. A clip where the facade bends, a sofa melts or the camera wanders into an invented room is a finished, paid generation.

That makes retakes the hidden line in any credit budget. Architecture is a hard subject for these models: straight lines, repeated windows and fine patterns show every error, and some shots need several attempts (why AI video warps buildings). How many takes a shot needs depends on the image, the move and the model, so there's no honest average; test one representative scene on the tool you're considering and count.

What a usable 30-second film costs in credits

Here is the arithmetic for six 5-second scenes, a common structure for a 30-second vertical film. Two scenarios: one take per scene, and two takes per scene. The second is an assumption for illustration, not a measured rate. Plan value is the plan price divided by its monthly credits, on monthly billing.

Three caveats keep this honest. The credit values assume you use the whole plan; if you don't, the real cost per film is closer to the full monthly price. The clip tools deliver six separate clips, so editing, music, captions and a 9:16 export are still your job, and that time isn't in the table. And the tools aren't equivalent: they differ in resolution, motion quality and how well they hold geometry. The tool-by-tool comparison for architects covers those differences.

Flat per-video pricing: what changes

A flat price per video replaces the credit arithmetic with one number. Arch2Video charges USD 15 per video as a one-time card payment on Stripe, with no subscription and nothing to cancel (plans). Uploading the six images costs nothing; the price is shown after the upload, and the video is made once paid. You can buy one or several videos at once, and unused videos stay on the account and don't expire. Each one is a finished 30-second, 1080 × 1920 film with six connected scenes and an original soundtrack, and after it's ready you can switch the soundtrack or logo and re-export without paying again. There is no free video.

What you give up is control. There are no prompts, no per-scene retakes and no editing timeline; the AI director plans the scene order, every film includes a small fictional cast, and generation usually takes an hour or more. If a scene doesn't work, the fix is a replacement image and a new film.

Which model suits you depends on how you work:

• Credits suit studios that want many clips, horizontal formats, longer shots or precise control of each camera move, and that will use most of a monthly plan.
• A flat price suits studios that want one finished film per project, a few times a year, with a known cost and no subscription to manage.

How to compare any two pricing pages

Prices and rates change often, so run this check on the day you buy:

1. Find the credits per second for the model you'll use, at the resolution you'll publish.
2. Work out the price per credit on the plan you'll actually buy, monthly or annual.
3. Read the rollover rule for monthly credits and the expiry of top-ups.
4. Check commercial use and watermarks on that plan (what free plans actually allow).
5. Look up the policy on failed generations in the help center.
6. Multiply by a realistic number of takes from your own test, then add the editing time.

Frequently asked questions

Do unused AI video credits roll over to the next month?

Usually not, for plan credits. As of October 2026, Runway's Standard and Pro monthly credits don't roll over, while Max rolls over up to one month; Luma's monthly credits don't roll over. Purchased top-ups are treated differently: Runway's never expire, and Luma's are valid for 12 months.

Do I lose credits when a generation fails or comes out wrong?

A generation that completes is charged whether or not the result is usable, so a warped clip costs the same as a good one. Whether a generation that errors out is refunded isn't stated on Runway's or Luma's pricing pages as of October 2026; check each vendor's help center.

Why does 1080p cost so much more than 720p?

Generating more pixels takes more compute, and vendors price that in. On Luma's Ray3.2, a 5-second clip costs 100 credits at 720p and 400 at 1080p as of October 2026. If the film will mostly be watched on phones, test whether 720p is good enough before paying the 1080p rate.

Is a per-video price cheaper than a credit plan?

It depends on volume and retakes. If you make many clips a month and use most of your credits, a credit plan can cost less per second. If you make one finished film per project, a flat price such as Arch2Video's USD 15 can cost less once retakes, expired credits and editing time are counted, but you trade away per-shot control.