How to Make an AI Avatar Video Without Paying for Minutes You Throw Away

What Do You Need Before You Make an AI Avatar Video?

You need a finished script, an account on an avatar video tool such as Synthesia or HeyGen, and a target length, because length sets the cost. An AI avatar video is a software-made presenter speaking the script you supply, so with a stock avatar and a built-in voice you need no camera and no microphone.

Here is Mimo’s arithmetic for a typical first video, from the vendors’ published rates. A 300-word script at the general speaking rate of about 150 words a minute (a common rule of thumb, not a vendor figure) runs about 2 minutes. On Synthesia that is about 200 credits at about 100 credits a minute, charged only once the 10 minutes every plan includes each month are used up (A-01, A-05). On HeyGen it is about 62 credits on Avatar IV Video Look at 31 a minute, or about 8 on Avatar III Video Look at 4 a minute (A-19). HeyGen’s Free plan uses no credits but caps each video at 1 minute (A-20, A-29).

Still choosing a tool? Synthesia vs HeyGen, priced side by side settles that question; this guide covers the making.

How to Make an AI Avatar Video From a Script, Step by Step

Make an AI avatar video in five steps: write the script, pick an avatar, choose a voice, render, and export. Synthesia and HeyGen follow the same order, and neither vendor documents a charge for any step except rendering, which is also the step a later fix sends you back to.

The same order applies on other avatar tools too: script, avatar, voice, render, export. What differs from tool to tool is how the render is metered, in included minutes, credits per minute or a set number of videos.

1. Script: write it in scenes before you open the editor. Synthesia treats a script as the spoken text of one scene and lets an audio file replace typed text (A-10, page dated 20 July 2026); HeyGen keeps scripts in short sections with an optional Pause button (A-25, A-26). Word count sets the length, and length sets the cost. Every word cut now is a word you never pay to render twice.
2. Avatar: start with a stock presenter. Both vendors include stock avatars with no creation step (A-11, 2 September 2026; A-20). On HeyGen the engine you choose also sets the rate in Table 1, and Synthesia notes some topics may call for a custom avatar under its moderation guidelines (A-13).
3. Voice: preview before you commit. Swap the pre-selected voice and play it back before generating: Synthesia from the script box (A-12), HeyGen at avatar level with a play button that reads the script aloud (A-25, A-24).
4. Render: check the cost, then generate once. In Synthesia select Generate at the top right, add a title, then Generate again (A-07); Synthesia asks users not to generate the same video several times (A-14). HeyGen charges the credit cost it shows before you generate (A-22, A-24).
5. Export: download what your plan allows. Synthesia downloads run through the video’s three-dot menu as .mp4 (A-09, A-06); HeyGen’s sit in the three-dot menu of the Projects tab (A-27, page dated 25 May 2026).

How to Check Credits Before You Render and Avoid a Paid Re-render

Check the per-minute rate for your avatar before you render, and make script fixes in preview. After rendering, Synthesia charges only for words you add or replace, with cuts, reordering and punctuation costing no extra credits, per its July 2026 edit table (A-04, A-02); HeyGen re-renders the whole changed A-Roll scene (A-23).

Table 1. What each step costs on Synthesia and HeyGen, per the vendors’ own help pages (read 28 October 2026)

Credit cost of each avatar video step on Synthesia and HeyGen, as stated on each vendor’s help pages captured 28 October 2026. Scrolls sideways on phones.

HeyGen’s credit page says its rates and limits can vary by account creation date and region, so the figure on your own screen wins (A-22). One Synthesia help page dated 22 July 2026 still shows an older 2 credits a second, 120 a minute; Synthesia’s October credits article says about 100 (A-03, A-01).

Where does a first avatar video waste credits?

Credits leak in three places a first-timer rarely budgets for. The first is the fix after rendering. Synthesia counts words: trimming a sentence or reordering a line adds no credits, but every word you add or swap in is charged for its spoken length (A-04). HeyGen counts scenes: one corrected line inside a rendered A-Roll scene sends that scene back through rendering (A-23). The second is upgrading late: Synthesia removes its Basic watermark only if you upgrade and generate the video again (A-08), so a video polished on the free plan gets rendered twice. The third is timing: Synthesia resets unused credits each billing period with no carry-over (A-01), while HeyGen carries monthly credits forward for one extra cycle only and sells no top-up packs on Creator or Pro (A-21). HeyGen’s own advice is the order this guide uses: preview the speech, fix the script, preview each scene, then render the whole video (A-23).

Of the 40 HeyGen reviews on the first two pages of Trustpilot’s most-recent sort, read on 28 October 2026 (dated 8 to 28 October 2026, plus one from January), 2 describe credits burning fast or a whole video rebuilt per correction, one citing about 150 credits for “one simple Avatar and one simple 30 second video” (A-40, A-35, A-36). Of the 20 Synthesia reviews on page 1 of the same sort (dated 3 July to 22 October 2026), 4 describe a video refused or delayed by moderation and 1 describes unused credits expiring, and neither sample reports credits charged for a failed render (A-41, A-37, A-38, A-39).

Plan by plan cost per finished minute lives in Mimo’s Synthesia review and the HeyGen review with its full credit ladder.

How to Make an AI Avatar Video for Free and Where the Free Plan Stops

You can make an AI avatar video for free on both Synthesia and HeyGen, and both free results carry a watermark. Synthesia’s Basic plan cannot download videos, and HeyGen’s Free plan caps each video at 1 minute while its Terms rule out commercial use, so a free plan suits a trial run rather than a finished asset.

Table 2. Free-plan limits on Synthesia Basic and HeyGen Free (captured 28 October 2026)

What the free plans of Synthesia and HeyGen allow, from each vendor’s pricing page, help pages and terms, captured 28 October 2026. Scrolls sideways on phones.

The free plan stops the moment the video has to leave the vendor’s site as a clean file. On Synthesia that point is the download itself (A-09); on HeyGen it is length, the watermark and the Terms (A-28, A-30). Both tools are free to start, and full, clean videos come with a paid plan. This section covers these two vendors only; other avatar tools’ free plans were not checked. The cheapest order is to draft and preview on the free plan, then do the final render after you upgrade, because on Synthesia an upgrade alone does not lift the watermark from a video already generated (A-08).

How to Make an AI Avatar of Yourself and What Consent It Needs

To make an AI avatar of yourself, you record a short consent video live, as the same person who appears in the avatar footage, and on Synthesia you need a paid plan. Synthesia refuses an uploaded pre-recorded clip and HeyGen refuses a screen recording of the consent text, and an avatar of another person needs that person’s own consent recording (A-16, A-31).

Both vendors match the person in the consent video to the person in the footage, and HeyGen also lets that person record by phone (A-16, SR-10, A-31, HR-06); how the two vendors’ consent checks compare sets the two flows side by side. On Synthesia an avatar of someone else is an Enterprise-only request (A-16). Table 3 keeps to the plan, time and voice limits you meet when the avatar is you.

Table 3. Custom avatar and voice clone limits on Synthesia and HeyGen (vendor pages, captured 28 October 2026)

The plan caps, waiting time and voice clone limits that apply to a custom avatar of yourself, from Synthesia’s documentation and help pages and HeyGen’s help pages, captured 28 October 2026. Scrolls sideways on phones.

Synthesia’s Customer Terms make the customer responsible for the person’s free and informed consent and legal age (A-18, effective 20 July 2026). HeyGen’s plans and voice limits are covered in Mimo’s review.

How to Make an AI Avatar Video From a Photo or Audio

To make an AI avatar video from a photo, build a photo-based avatar inside the tool and then follow the same five steps; to start from audio, upload the recording in place of a typed script. Synthesia offers photo-based personal avatars on paid plans and recommends them over video-based ones for new content (A-13, A-16).

Synthesia lists four avatar routes: stock, customizable synthetic stock, custom (from an image, a video recording or a studio shoot) and Avatar Builder, and it calls the video-based personal avatar legacy technology (A-13, page dated 9 October 2026). The live consent rule applies to photos too: the person in the consent video must be the person in the photo (A-16). HeyGen prices photo avatars per minute like any other: Avatar III Photo Look 7 credits and Avatar IV Photo Look 16 (A-19). For audio, Synthesia’s script box takes an uploaded audio file instead of text (A-10).

How to Publish an AI Avatar Video on YouTube

To publish an AI avatar video on YouTube, render it on a plan that gives you a clean downloadable file and allows commercial use, then upload the MP4 like any other video. HeyGen’s Terms make Free output non-commercial, and Synthesia’s Basic plan cannot download a file at all (A-30, A-09).

For a 1080p upload, Synthesia’s paid plans list Full HD 1920 x 1080 MP4 downloads (A-06), and HeyGen exports 1080p from Creator and 4K from Pro (A-20, A-27). HeyGen’s download article for paid users says its videos may be used on any platform, commercially included, as long as the inputs follow its guidelines (A-27). Whether a channel can earn from avatar videos, and how YouTube wants synthetic presenters labelled, are YouTube policy questions outside this guide’s sources, so read YouTube’s own help pages before you publish. For videos with no presenter at all, see the clip generators in Mimo’s video rankings.

How Was This AI Avatar Video Guide Built?

Mimo made no avatar videos for this guide. Every step and rate comes from Synthesia’s and HeyGen’s own help pages, pricing pages and terms, read on 28 October 2026 (credit rates and plan prices re-read on 31 October) and labelled as the vendor’s statements, plus two counted Trustpilot samples. Two independent coding passes agreed on 40 of 41 entries; the one split was settled by dropping an inference its source page does not state. The full method is in the evidence protocol behind this guide.

Limitations. Synthesia changed its plans on 1 October 2026 and its help centre is mid-change: pages from July 2026 still speak of minutes and of 2 credits a second (A-05, A-03). HeyGen’s credit page was updated in October 2026 and says rates vary by account date and region (A-19, A-22), so confirm the cost on your own screen before rendering. Every rate here is the vendor’s own statement; no independent measurement of render cost exists in this record. The community layer is Trustpilot only, read through a page summarizer, in samples of 40 and 20 reviews that were each coded once; review platforms skew toward strong complaints, and these samples describe their reviewers, not every user. Reddit, Capterra, Quora and G2 could not be reached this run, so no claim rests on them. Synthesia’s Customer Terms captured here say nothing plain about commercial use on Basic, and neither vendor states a price for previews or downloads.