Runway AI Models Compared: Gen-4.5, Aleph 2.0 and Act-Two

For a new clip from a text prompt or a still image, Runway's default model in November 2026 is Gen-4.5: clips of 2 to 10 seconds at 720p, 12 credits a second, on the Standard plan and higher, outside the mobile apps. It has no sound of its own. When the job changes, so does the model. Aleph 2.0 edits footage you already have, Act-Two turns a recorded performance into a character's, and the same plan opens other labs' models, such as Kling 4.0, Veo 3.1 and Seedance 2.5, that add audio in the same pass or run past 10 seconds. Gen-3 and Gen-2 are retired. If an old tutorial sends you there, Gen-4.5 handles generation and Aleph 2.0 handles edits.

Gen-4.5 is the starting point, with three hard edges

Runway released Gen-4.5 in December 2025 and added image to video with a first frame in January 2026. It takes a text prompt or an image and returns a clip of 2 to 10 seconds at 720p, at 24 or 25 frames a second, in six aspect ratios: 16:9, 9:16, 1:1, 4:3, 3:4 and 21:9. You reach it in the desktop web app, the Premiere Pro, After Effects and DaVinci Resolve plugins, Runway MCP and the API, but not in the iPhone or Android apps. The rate is 12 credits a second, so a 5-second clip costs 60 credits and a 10-second clip 120 ^[1].

The three edges are length, resolution and sound. Ten seconds is the ceiling. Anything longer gets assembled from several clips in an editor. Output stops at 720p. Runway's own guide also says Gen-4.5 does not generate embedded audio, so voice, effects and music come from Runway's audio tools or from a model with native sound. Runway is candid about two more weak spots. Its limitations list names mistakes in cause and effect, objects that fail to stay consistent, and a bias toward actions that succeed. Its resource page also concedes that newer models now exceed Gen-4.5 on shot length. On Max, Gen-4.5 can output HDR directly.

Gen-4 and Gen-4 Turbo keep a narrow job

The older pair need an input image as the first frame and return 5 or 10 seconds at 24 frames a second. Gen-4 Video charges the same 12 credits a second as Gen-4.5, which leaves it little reason to exist for new work. Gen-4 Turbo is the exception. At 5 credits a second, or 25 for a 5-second clip, it is the cheap way to check whether a still image animates well before you pay the Gen-4.5 rate for the version you keep. Runway's developer docs name Gen-4 Turbo and Gen-4.5 as the way forward for anyone who relied on the retired Gen-3 Alpha Turbo.

Aleph 2.0 and Act-Two start from footage, not a prompt

Aleph 2.0 arrived in May 2026 together with Edit Studio, and it edits video rather than inventing it. You give it 2 to 30 seconds of footage, real or generated, at 480p to 1080p and 24 to 30 frames a second, with up to 10 cuts; longer input is trimmed and faster input is down-sampled. A text instruction plus an edited keyframe tells it to add, remove, replace, re-light or re-style objects and whole scenes, and it can carry one edit across several shots. Expand Ratio changes the aspect ratio by generating new picture at the edges. It runs on desktop web for paid plans at 28 credits a second with a 56-credit minimum, and in Edit Studio only the edited range is charged ^[2].

Runway is explicit that Aleph is not a lip-sync model. The first Aleph shipped in July 2025, and the older Gen-4 Aleph still costs 75 credits per 5 seconds. Keyframe previews carry their own price per image: 20 credits with Nano Banana Pro, 8 with Gen-4 Image and 5 with GPT Image 2. That ladder matters, because you may try several keyframes before a single full render. Our Aleph editing guide walks through the keyframe workflow step by step.

Act-Two, from July 2025, is performance capture. A driving video of one person, face visible, framed waist-up at most and with no cuts, drives a character image or video for up to 30 seconds at 24 frames a second. It handles one character per generation. Dialogues take extra work. Each character is generated separately and the takes are composited in an editor. Facial expressiveness runs on a scale of 1 to 5, gesture control works only with a character image, and the voice can be swapped afterwards. It costs 5 credits a second with a 3-second minimum, and it replaced the Lip Sync tool, which Runway retired in May 2026. The Act-Two guide covers the driving-video rules.

Other labs' models share the same credit balance

This is where Runway parts ways with single-model tools: Standard and higher plans open third-party video models in the same workspace, billed from the same credits. Kling 4.0 runs 3 to 30 seconds at 720p or 1080p with sound generated in the same pass. It accepts up to 10 images and 5 clips as input, takes up to 8 middle keyframes, and can edit one clip of up to 30 seconds. On Runway it costs 118 credits per 5 seconds at 1080p, or 89 under a 25% promotion that ends November 30, 2026 ^[3]. Runway's hosting has no 4K yet, although Kling's own site outputs it. Kling 3.0 covers 3 to 15 seconds with audio on or off.

Seedance 2.5 also reaches 30 seconds, at 480p, 720p or 1080p, with up to 50 references and Reference, Keyframe, Edit and Extend modes. It charges 68 credits a second at 1080p, 30 at 720p and 20 at 480p, plus half that rate per second of input video. Seedance 2.0 runs 5 to 15 seconds at up to 1080p. Veo 3.1 returns 4, 6 or 8 seconds with audio on or off, at 320 credits per 8 seconds with audio, and needs no Google account inside Runway.

The rest of the menu is thinner on published detail. Gemini Omni Flash gives 3 to 10 seconds at 720p, and MiniMax H3, Wan 3.0 and Grok Imagine 1.5 sit alongside it. For any model without a listed rate, the cost shows before you generate. Error messages from third-party models can be vaguer than Runway's own. Sora 2 left Runway on April 3, 2026.

What one month of credits covers on each model

Runway shows the total cost of a generation before you start it, and the per-model rates above are not always the whole bill. ProRes or PNG-sequence output adds 5 credits a second, which takes Gen-4.5 to 17 a second. The plan sets the budget: Standard is $15 a month with 625 credits, Pro is $35 a month with 2,250 credits and Max is $95 a month with 9,500 credits.

By our arithmetic, Standard's credits cover about 52 seconds of Gen-4.5 a month, roughly ten 5-second clips; Pro covers about 187 seconds and Max about 791. Editing and audio models drain faster. Standard pays for 4 five-second Aleph 2.0 edits, Pro 16 and Max 67. Eight-second Veo 3.1 clips with audio come to 1, 7 and 29. At 1080p, Seedance 2.5 gives about 9, 33 and 139 seconds, and Kling 4.0 gives 5, 19 and 80 five-second clips, or 7, 25 and 106 while the promotion lasts. Act-Two and Gen-4 Turbo stretch furthest: 125, 450 and 1,900 seconds.

Top-ups on paid plans cost $10 for 1,000 credits and never expire. At that rate a 5-second Gen-4.5 clip costs $0.60, a 5-second Aleph 2.0 edit $1.40 and an 8-second Veo 3.1 clip with audio $3.20. Those are per attempt. Credits come back only for generation errors, so a clip that fails your eye still costs its credits, and Runway's own guide says to judge cost per usable output. Plan credits on Standard and Pro reset at each billing date, while Max and Team carry one month over; the pricing breakdown covers rollover and top-ups.

Gen-3, Gen-2 and the retired names you can no longer pick

Retired models still surface in search results and tutorials, but none of them can be selected in Runway any more. Gen-1 was retired in April 2025, and Gen-2 was retired in May 2025 along with Motion Brush. Gen-3 Alpha and Gen-3 Alpha Turbo were retired in mid-2026, and Gen-3 Alpha Turbo left the API as well ^[4]. The old video editor and the inpainting and mask tools gave way to Edit Studio and the Remove from Video app.

Old tutorials still help with prompt ideas. Their settings do not carry over. Prompts written for the retired Gen-3 Alpha now go to Gen-4.5. Image-to-video jobs from the retired Gen-3 Alpha Turbo move to Gen-4.5 or Gen-4 Turbo, as Runway's developer docs recommend, and a Gen-4 Aleph edit moves to Aleph 2.0. A lip-sync job becomes an Act-Two performance. Expect the menu to keep shifting: in 2026 Runway added Kling 4.0, Seedance 2.5 and Aleph 2.0, and removed Sora 2.

The bottom line

Pick the model by the job, not by the newest name. Gen-4.5 fits short, silent 720p shots from a prompt or an image; Gen-4 Turbo is the low-cost draft pass. Aleph 2.0 changes footage you already own, and Act-Two puts a real performance on a character. When a shot needs sound, more than 10 seconds or 1080p, the hosted Kling 4.0, Seedance 2.5 or Veo 3.1 cover it on the same plan at higher credit rates. Check the estimate before every render.