Runway Gen-4.5 vs Veo 3.1: Which AI Video Model to Use

Runway Gen-4.5 vs Veo 3.1 comes down to sound and shape: Veo 3.1 generates video with built-in dialogue and sound in 4, 6 or 8 second clips at 16:9 or 9:16, while Runway Gen-4.5 is a picture-first model known for realistic motion, offered in 5 or 10 second clips and more aspect ratios, with sound added separately. Pick Veo for a short shot where someone speaks; pick Runway for silent footage and wider format choice.

Below is a side-by-side based on Google's and Runway's own pages, the cost per second on each platform and in QuickVeed, a table of which to use for common jobs, and a simple test to settle it for your own shots.

The short answer

Use Veo 3.1 when the clip needs synchronized sound or a spoken line, or when you want first-and-last-frame control and up to 2160p through Google. Use Runway Gen-4.5 for silent, realistic B-roll and product shots, longer 10-second clips, or square and ultra-wide shapes. Both are premium models, so draft on a cheaper model first and test the same prompt on each.

Key takeaways

• Runway Gen-4.5 launched in December 2025 and topped the Artificial Analysis text-to-video leaderboard at launch, by Runway's account.
• Veo 3.1 always generates sound; in QuickVeed, Runway Gen-4.5 makes silent clips that you add sound to afterwards.
• Veo 3.1 gives 4, 6 or 8 seconds in 16:9 or 9:16; Runway Gen-4.5 in QuickVeed gives 5 or 10 seconds in more shapes.
• On their own platforms, Veo 3.1 costs $0.40 a second on Google's API; Runway Gen-4.5 is 12 Runway credits a second.
• Runway lists its own model's weak spots: cause and effect, objects that appear or vanish, and actions that succeed too easily.

Disclosure: we make QuickVeed and show how to do this in it, along with other ways. Details about other products come from their public pages, checked in October 2026 and linked at the end.

Runway Gen-4.5 vs Veo 3.1 at a glance

Specs below come from Google's Gemini API documentation for Veo 3.1 and from Runway's Gen-4.5 announcement and pricing page, checked in October 2026. Where a figure is how QuickVeed offers the model, it says so.

The headline difference is sound. If you need a person to say a line in the clip itself, Veo does that in one pass. If you're going to lay your own voiceover and music over the footage anyway, Runway's lack of native sound in this comparison doesn't cost you anything.

Picture quality and motion

Both models are at the top end for realism. Runway's launch post says Gen-4.5 held the top spot on the Artificial Analysis text-to-video benchmark with 1,247 Elo, ahead of Veo 3 at 1,226, in the leaderboard of November 30, 2025. That was Veo 3, not Veo 3.1, and rankings move every few weeks, so treat it as a sign the two are close rather than as a verdict.

In practice the differences show up shot by shot:

• Runway Gen-4.5 is strong on physical motion and texture: fabric, liquid, hair, camera moves through a space. That makes it a good B-roll and product-shot model.
• Veo 3.1 is strong on following long, specific prompts, including camera language, and on people who talk and react, because the sound and picture are made together.

Runway is unusually candid about Gen-4.5's limits. Its announcement lists three: causal reasoning (an effect can appear before its cause), object permanence (things can vanish or appear between frames) and success bias (actions succeed more often than they should, like a badly aimed kick still scoring). Veo has similar failure modes. Check every clip for objects that pop in or out, and for hands and text.

Sound: the deciding factor for many shots

Veo 3.1 generates audio with every clip. You write the dialogue as “the woman says: ...” and describe effects and ambience in their own sentence, and they come back in sync. That saves a whole step for talking shots, ads with a line to camera and scenes where a sound sells the action, such as a sizzling pan.

Runway Gen-4.5 in QuickVeed produces a silent clip. Runway's own paid plans include separate music, voice and sound-effect tools, so inside Runway you can add audio in a second step. Elsewhere, you add sound in your editor: a voiceover from an AI voice tool, licensed music and a few effects.

If sound is the reason you're comparing models, our guide to AI video generators with sound covers every model that makes audio and how to prompt for it.

Cost per second

On their own platforms the two price differently, so here they are per second of finished video, from the public pricing pages in October 2026:

Runway's free plan (125 one-time credits) doesn't list Gen-4.5; it appears on Standard and above. Google's API has no free tier for Veo.

Per-second prices hide the real cost driver, which is how many attempts a shot takes. A model that gets the shot right on the second try is cheaper than a cheaper model that needs six. Track attempts per usable clip for a week and you will know which model is actually cheaper for your kind of work.

In QuickVeed you pay in QuickVeed credits and see the price before generating. An 8-second Veo 3.1 clip with audio is 800 credits and Veo 3.1 Fast is 300; Runway Gen-4.5 is priced per clip on screen when you choose 5 or 10 seconds. Failed generations are refunded either way.

Prompting tips for each model

The same core prompt works on both, but each responds to slightly different emphasis.

Runway Gen-4.5

• Lead with the motion and the physical detail: “steam curls up slowly”, “silk ripples in a light breeze”.
• Use one camera move per clip and say how fast: “slow dolly forward”, “gentle handheld drift”.
• Leave sound out of the prompt; it won't be generated, and the words can distract the model.
• Watch for objects appearing or disappearing, which Runway itself names as a known weakness.

Veo 3.1

• Write it like a director's note: framing, subject, action, setting, light, then sound in its own sentence.
• Put dialogue in quotes after the speaker's name, one sentence per 8-second clip.
• Use the first and last frame option for reveals, and up to three reference images for a consistent person or product.
• Describe what you want rather than writing “no ...”; Google's prompt guide recommends this.

If one prompt gives very different results on the two models, that's useful information: it usually means the prompt is vague. Tighten the subject and action until both models produce something similar, then judge on quality.

Which to use for common jobs

For Google's model in more depth, read what Google Veo 3 is. If Kling is also on your list, see Veo 3.1 vs Kling v3.

Test both on your own shot in QuickVeed

A spec sheet won't tell you which model handles your product, your style or your kind of scene. A ten-minute test will. QuickVeed runs both models, so you can do it from one account.

1. Open the AI video generator and write one prompt for a shot you actually need: subject, action, setting, camera, light, and a sound sentence for Veo.
2. Generate it on Veo 3.1 Fast at 8 seconds and on Runway Gen-4.5 at 5 seconds, both in 16:9 or both in 9:16.
3. Watch each clip three times: for motion, for faces, hands and text, and (for Veo) with your eyes closed for sound.
4. Score each out of 5 on prompt accuracy, motion, artefacts and usefulness, and note the credits each cost.
5. Render the winner at final settings. Use full Veo 3.1 only if the shot is the one the whole video depends on.

Keep a note of which model won for which kind of shot. After a handful of tests you'll have your own rules, which beat any general ranking. Prompt tips that work on both models are in how to write prompts for AI video generators.

Frequently asked questions

Is Runway Gen-4.5 better than Veo 3.1?

Neither wins everywhere. Runway Gen-4.5 is strong for silent, realistic motion and offers more shapes and 10-second clips. Veo 3.1 is better when the clip needs sound or a spoken line, or first-and-last-frame control.

Does Runway Gen-4.5 generate audio?

In QuickVeed, Runway Gen-4.5 clips are silent. Runway's own paid plans include separate music, voice and sound-effect tools, so check Runway's app for its current audio options.

How long are Runway Gen-4.5 videos?

In QuickVeed you choose 5 or 10 seconds. Longer videos are built by joining clips.

Which is cheaper, Runway or Veo?

On Google's API, Veo 3.1 Fast ($0.10-$0.12 a second) is cheaper than Runway Gen-4.5 on a Standard plan (about $0.29 a second of included credits); full Veo 3.1 at $0.40 a second is dearer.

Can I use Runway Gen-4.5 for free?

Runway's free plan gives 125 one-time credits but lists Gen-4.5 only on paid plans. QuickVeed's 14-day trial includes 75 credits, which suits a cheaper model test.

Try it with your own video

Run the same prompt on Veo 3.1 Fast and Runway Gen-4.5 and compare. Write one prompt, generate it on both models, and judge the motion and the sound for yourself. QuickVeed plans start at $18/month, and new accounts get a 14-day trial with 75 credits, no card needed. Sign up or see pricing.

Sources

Competitor details in this post were checked against these public pages in October 2026. Products and prices change, so confirm with each vendor before you decide.

• Runway Research: Introducing Gen-4.5 (Dec 2025)
• Runway pricing (plans, credits, Gen-4.5 per plan)
• Runway Help: Creating with Gen-4.5 (durations, 720p, aspect ratios)
• Google Gemini API: Veo 3.1 documentation (lengths, resolutions, extension, SynthID)
• Google Gemini API pricing (Veo 3.1 per-second prices, no free tier)
• Google blog: Introducing Veo 3.1 and advanced capabilities in Flow (Oct 15, 2025)