How to Create an AI Podcast | Generate Audio Content from Text Automatically

I want to turn my blog posts into a podcast, but I don't have a microphone or editing skills...

Have you ever wanted to share the contents of your blog or documents as a podcast?

These days, you can create a podcast simply by entering text using AI tools.

In this article, we'll compare five tools that can create AI podcasts from text and explain exactly how to make one.

What you'll learn in this article

• Features and differences of five tools that can create AI podcasts from text
• How to choose the right tool for your needs
• Step-by-step instructions for turning a blog post into a podcast
• Tips for improving the quality of AI-generated podcast audio
• Ondoku pricing plans for distributing audio created with Ondoku as a podcast

5 AI tools for creating podcasts from text

Tools that generate audio content with AI simply by entering text or an article URL are appearing one after another.

First, here are five recommended AI podcast generation tools that you can use in Japanese.

1. Ondoku: Create audio your way. Distribution available with the business plan

『Ondoku』 is a text-to-speech service that generates high-quality AI voices simply by entering text.

The generated audio can be downloaded as an MP3 file, so you can use it as a podcast audio track right away.

Its greatest appeal is its wide variety of voices available in multiple languages.

You can also fine-tune the speaking speed and pitch, creating a voice that perfectly suits the content and mood of your podcast.

By subscribing to Ondoku's business plan, you can also distribute and sell your podcast.

With the conversation feature, you can also manually create dialogue-style content that switches between two voices.

This is the ideal tool for anyone who wants to create narration-style podcasts or customize voices to their liking.

2. Google NotebookLM: Automatically generate a dialogue-style podcast just by entering a URL

Google NotebookLM is a tool that automatically generates a podcast in which two AI hosts explain the content in a dialogue format simply by entering a URL or PDF.

Japanese has been supported since April 2025, and the tool is free to use.

It's easy to use: just add a source (URL or PDF) and click “Generate Audio Overview.”

It's convenient, but the voice options are limited, and you can't fine-tune the speaking speed or tone.

Also, it can't read your own text aloud as-is.

Because it reads out content automatically summarized by AI, if you want to create the content yourself, we recommend a tool that can read text aloud as-is.

3. castmake: An AI radio generation service optimized for Japanese

castmake is a Japan-based service that can generate an AI radio show in about three minutes just by entering a blog post URL.

One feature is that it can introduce the contents of up to five articles from a single source article, making it easy to create content like a digest show combining multiple articles.

It also supports RSS distribution to Apple Podcast and Spotify, so you can handle everything from generation to distribution in one place.

It's a perfect service for anyone who wants to turn Japanese content into audio in a dialogue format.

However, you can't fine-tune the voice options or tone.

4. ElevenLabs GenFM: Generate podcasts with high-quality AI voices

ElevenLabs is a service known for its high-quality AI voice synthesis.

With its podcast generation feature, “GenFM,” you can automatically create a dialogue-style podcast from text, PDFs, or URLs.

It supports 32 languages, and you can also edit the generated script afterward.

You can also fine-tune the content generated by AI yourself.

The audio quality is among the best, but a paid plan (starting at $5 per month) is required.

However, the interface is available only in English. Japanese is not supported.

5. Monica AI: A free AI podcast generation tool

Monica AI is a free AI podcast generation tool that supports various formats, including text, PDFs, and URLs.

Enter your content, and AI will automatically convert it into podcast-style audio.

This tool is recommended for anyone who wants to try AI podcasting for free.

Comparing AI podcast generation tools

Let's compare the five podcast creation tools introduced so far.

You can create audio with Ondoku's free plan, but to distribute it on podcast apps, you need to subscribe to the business plan (starting at ¥120,000 per year, excluding tax).

We'll explain how to choose a plan based on your distribution platform and how you plan to use it later in this article.

How to choose an AI podcast tool based on your needs

We've introduced five tools, but many of you may be wondering, “Which one should I choose?”

The key to choosing a tool is to think about what kind of podcast you want to create.

When you want to easily create high-quality podcast audio

If you want to turn your blog into a podcast with comfortable-sounding narration, we recommend 『Ondoku』.

You can choose a voice that suits the mood of your show from over 692 options. For example, you can use a mature woman's voice for a calm explanatory show, or a bright-toned voice for a casual show.

In addition to adjusting speed and pitch, you can also specify the tone and reading style, so it can accommodate detailed requests like “Please read a little more slowly and gently.”

You can download the generated audio as an MP3, then simply add background music to create a full-fledged podcast.

When you want to easily create a dialogue-style podcast

If you want to create a radio-style podcast where two hosts explain things in conversation, NotebookLM or castmake can be useful.

Both tools can automatically generate a dialogue-style podcast with AI simply by entering a URL or text.

NotebookLM is provided by Google, and its main advantage is that it's free to use.

castmake is a Japan-based service, so it works well with Japanese content and supports distribution to Apple Podcast and Spotify.

If you want to pursue even better audio quality or edit the generated script yourself, ElevenLabs' GenFM is also a good option.

How to create a podcast with Ondoku

Here, we'll show you how to create a podcast from a blog post using 『Ondoku』.

First, edit the text of your blog post to make it sound more conversational.

Reading written text as-is can sound stiff, so it's easy to ask ChatGPT something like, “Convert this text into conversational language for a podcast.”

Next, open the 『Ondoku』 page.

This time, we'll use 『Ondoku Beta』 to create audio with a more realistic, easy-to-understand voice.

Once the page opens, first paste in the text you prepared.

Choose your preferred voice.

Ondoku Beta also lets you select a reading style.

For podcasts, we recommend “Narration,” “Calm,” or “Storytelling.”

You can also freely specify the reading style to suit your preferences.

You're all set.

Click “Generate audio” to start generating.

Generation finishes quickly.

The screen switches, and the audio file starts playing.

Listen to the audio, and if it sounds good, download it as an MP3.

Reading the text used in this example produced audio like this.

Audio sample

That's the full process for creating podcast audio with Ondoku.

Add background music if you like to give your podcast a more professional finish.

If you want a dialogue-style podcast with two different voices, you can also use Ondoku's conversation feature to switch between speakers as you create it.

As you can see, Ondoku makes it easy to create podcast audio.

By subscribing to the business plan, you can also distribute and sell your audio on services such as Spotify.

Why not try Ondoku's AI text-to-speech for free first?

Tips for creating easy-to-understand AI podcast audio

Next, we'll cover a few tips for improving the quality of AI-generated podcasts.

We recommend converting written text into conversational language

Reading the text of a blog post as-is will inevitably make the audio sound stiff.

That's why we recommend using an AI service to convert written text into conversational language.

Standardizing the text in a polite style and keeping sentences short will make for an easy-to-understand script.

We recommend asking a generative AI service such as ChatGPT to convert the text like this.

Example prompt

“Please convert the following blog post text into conversational language for reading aloud in a podcast. Keep the sentences short and use a consistent polite style.”

Aim for 2,000–3,000 characters per episode

The length of a podcast script depends on the AI voice's reading speed, but 2,000–3,000 characters will make an episode of about 10 minutes.

People often listen to podcasts while commuting or doing housework, so an episode of around 10–15 minutes is just right.

A reading speed of 1.0–1.1x is recommended

For podcasts, the easiest speed to follow is the standard speed (1.0x) or just slightly faster at 1.1x.

With 『Ondoku』, you can adjust the speed to suit your preferences.

With Ondoku Beta, you can also change the speed by specifying the reading style.

Keep the background music volume low

If you add background music, a volume balance of around narration 70: background music 30 is best.

If the background music is too loud, it will be hard to hear the content, so the key is to adjust the balance so that the voice is clear.

You can download free background music from websites such as “DOVA-SYNDROME” and “Amacha Music Studio.”

Recommended podcast distribution platforms

Once your podcast audio file is ready, it's time to distribute it.

If this is your first time distributing a podcast, we recommend starting with Spotify for Podcasters.

You can create an account for free and start distributing right away just by uploading an MP3 file.

What's more, it automatically distributes your podcast to other apps such as Apple Podcasts and Amazon Music, not just Spotify, so you can reach most listeners by signing up with just one service.

Important notes when distributing audio created with Ondoku on Spotify

To create audio with Ondoku and distribute or sell it as a podcast on services such as Spotify, you need to subscribe to the business plan.

The business plan starts at ¥120,000 per year (excluding tax) and is available to individuals as well as businesses.

Podcast audio created using audio generated with Ondoku while your business plan is active can remain publicly available without credit attribution even after your subscription ends.

We recommend first creating some audio with the free plan and then subscribing to the business plan.

※If you want to distribute audio generated before subscribing to the business plan, such as audio created as a test with the free plan, please see the page on how to contact us and get in touch.

Learn more about the business plan in this article.

Details about the business plan for the text-to-speech software “Ondoku,” including features and pricing

A business plan exempts you from some restrictions on prohibited uses. We'll explain in detail what you can do with Ondoku's business plan.

We also recommend distributing audio on YouTube

Another option is to combine audio with still images or slides to create and upload a video.

For videos on YouTube and other platforms, you can use audio created with Ondoku without subscribing to the business plan.

However, with the free plan, you must include credit attribution such as “Narration: Ondoku” in the video or its description using the credit attribution.

With a paid plan starting at ¥980 per month (excluding tax), you can publish videos without credit attribution while your subscription is active.

If you continue to publish the video after your paid plan ends, you will need to include credit attribution, just as with the free plan.

For audio created while your business plan is active, you can continue publishing it without credit attribution after your subscription ends.

For more details on credit attribution when using audio created with Ondoku, including narration for YouTube videos, see this article.

How to credit Ondoku: Examples and important notes

We'd love for you to use Ondoku for free. However, credit attribution is required when using it for free. We received the question, “So, how exactly should I credit it?” Here's what you need to know about credit attribution when using Ondoku for free...

Summary: How to create a podcast using AI voices

In this article, we introduced how to create a podcast from text using AI services.

If you want a narration-style podcast with carefully chosen voices and delivery, 『Ondoku』 is the ideal choice.

You can choose your favorite voice from over 692 options and freely adjust the speed and pitch.

With a business plan, you can also use it to distribute and sell podcasts.

If you want to easily create a dialogue-style podcast, NotebookLM or castmake are good options. If audio quality is your priority, ElevenLabs is also useful.

Choose the tool that suits your needs and why not start your own AI podcast?