📊 Our Test Results:
- 🎯 音声リアリズム: TTSOpenAI scored 9/10 vs NaturalReader 7/10 — TTSOpenAI wins
- 💰 Cost for 200K Characters: TTSOpenAI $8 vs NaturalReader $49/mo — TTSOpenAI wins
- 📁 ファイル形式のサポート: NaturalReader 20+ types vs TTSOpenAI text-only — NaturalReader wins
- ⚡ 生成速度: TTSOpenAI 3 seconds vs NaturalReader 5 seconds — TTSOpenAI wins
- 🔌 開発者API: TTSOpenAI full REST API vs NaturalReader none — TTSOpenAI wins
Are you tired of robotic voices ruining your audio projects?
あなたには テキスト読み上げ tool that sounds like a real person.
NaturalReader and TTSOpenAI are two popular choices in this space.
One has been around for 15 years. The other runs on OpenAI’s newest voice engine.
We tested both tools head-to-head to find the winner.
概要
We spent weeks testing NaturalReader vs TTSOpenAI side by side.
We generated voiceovers, tested every voice, and compared pricing dollar for dollar.
We also checked file support, API access, and real-world audio quality.
This guide shares our firsthand experience so you can pick the right tool.
TTSOpenAIとは何ですか?
TTSOpenAI is a browser-based text to speech platform powered by OpenAI’s voice engine.
It converts written text into natural sounding audio in seconds.
You type your text, pick a voice, and download the audio as an MP3 file.
The platform offers six premium voices like Alloy, Nova, Echo, and Shimmer.
Developers can also connect through a REST API to build voice features into their apps.
TTSOpenAI
Turn your text into ultra-realistic audio with OpenAI’s voice engine. Pay only for what you use with the flexible credit system. Free tier included.
TTSOpenAIの価格
Here’s what TTSOpenAI costs in 2026. The pricing is simple and flexible.
| プラン | 価格 | 最適な用途 |
|---|---|---|
| 使った分だけ支払う | $0.00004/credit | Everyone — buy only what you need |
無料トライアル: Yes. You get 2,000 free characters to test all voices. No credit card needed.
返金保証: Credits do not expire for 60 days after purchase.
📌 注記： One character equals one credit. For 200,000 characters of audio, you pay just $8. There are no monthly subscriptions or auto-renewal fees.
⚠️ Warning: Credits are non-refundable once purchased. Start with the free tier to test voice quality before buying a credit pack.
Key Benefits of TTSOpenAI
Here’s why TTSOpenAI stands out from the competition:
- 自然な音声: The OpenAI voices like Nova and Alloy sound nearly human. They handle tone, pauses, and emotion better than most competitors.
- Pay-As-You-Go Pricing: No monthly fees or subscriptions. You buy credits when you need them. Perfect for occasional users and フリーランサー.
- 開発者API: The REST API is clean and well documented. Developers can add voice features to apps and チャットボット 数分で。
- Custom Voice Maker: Create a custom voice from a 60-second audio sample. Great for branding and personalized content.
- Story Maker Tool: Generate speech from story templates with built-in emotion controls. This adds expression to audiobook and e-learning projects.
- 複数言語のサポート: Generate speech in 29+ languages including English, Spanish, French, and Japanese.
TTSOpenAI Pros & Cons
✅ Pros
- Ultra-realistic voice quality powered by OpenAI
- Flexible pay-as-you-go model with no monthly fees
- Developer-friendly REST API for app integration
- Free tier with 2,000 characters to test before buying
- SSML support for fine-tuning speed, ピッチ, and pauses
❌ Cons
- Only 6 built-in voices compared to 1,000+ on NaturalReader
- Cannot read PDF, DOCX, or EPUB files directly
- No built-in audio editor or timeline
- No mobile app or Chrome extension
NaturalReaderとは何ですか?
NaturalReader is a text to speech tool that has been around for over 15 years.
It converts PDFs, Word documents, ebooks, and web pages into spoken audio.
The platform offers over 1,000 AI voices in more than 100 languages.
It works as a web app, mobile app, and Chrome extension.
Over 1 million people use NaturalReader every month for reading and accessibility.
ナチュラルリーダー
Listen to any document, webpage, or ebook with 1,000+ AI voices. Supports 20+ file formats and works on every device. Free plan available.
NaturalReader Pricing
Here’s what NaturalReader costs in 2026. Let’s break it down.
| プラン | 価格 | 最適な用途 |
|---|---|---|
| 無料 | 月額0ドル | Basic voices and limited premium time |
| シングルプラン | 月額49ドル | Individual users who need full access |
| チームプラン | 月額79ドル | Small teams sharing one account |
無料トライアル: Yes. The free version gives unlimited basic voices and 20 minutes per day of premium voices.
返金保証: Yearly plans get 30 days. Monthly plans get 14 days. You must request the refund separately.
📌 注記： NaturalReader has separate personal and commercial plans. The personal version audio is for your ears only. You need the commercial plan to share audio publicly.
⚠️ Warning: All plans auto-renew at the end of each billing cycle. Canceling your plan does not trigger an automatic refund. You must request one separately.
Key Benefits of NaturalReader
Here’s why NaturalReader stands out from the competition:
- Massive File Support: Reads 20+ file types including PDF, DOCX, EPUB, TXT, and even images. Few TTS apps match this range.
- 1,000+ AI Voices: Offers voices in over 100 languages and dialects. One of the widest selections available in any TTS tool.
- AI Text Filtering: Removes URLs, footnotes, and other distracting text while reading. This keeps the audio clean and focused.
- クロスプラットフォームアクセス: Works as a web app, mobile app on iOS and アンドロイド, and Chrome extension. Start on your phone and continue on your laptop.
- OCR Camera Scanner: Point your phone at printed text and NaturalReader reads it aloud. Great for physical books and documents.
- アクセシビリティの焦点: Designed for people with dyslexia, ADHD, and reading disabilities. Used by over 2,000 educational institutions.
NaturalReader Pros & Cons
✅ Pros
- Reads 20+ file formats including PDF and EPUB
- 1,000+ voices in 100+ languages and dialects
- Works on web, mobile, and Chrome extension
- AI text filtering removes distracting content
- OCR scanner reads printed text from your camera
❌ Cons
- $49/month is expensive compared to pay-as-you-go options
- Voice quality trails newer AI-powered competitors
- Free version limits premium voices to 20 minutes per day
- No developer API for custom app integration
機能比較
Ready to dive into a detailed comparison of NaturalReader vs TTSOpenAI?
We’ll explore 10 key features to help you determine which tool best suits your needs.
| 特徴 | TTSOpenAI | ナチュラルリーダー |
|---|---|---|
| 開始価格 | $8/200K chars | 月額49ドル |
| 無料プラン | ✅ 2,000 chars | ✅ Limited daily use |
| 音声品質 | ✅ OpenAI engine | ✅ Standard AI |
| File Format Support | ❌ Text only | ✅ 20+ formats |
| 開発者API | ✅ REST API | ❌ |
| 音声クローン | ✅ Custom Voice Maker | ✅ Voice Cloning |
| モバイルアプリ | ❌ | ✅ iOS & Android |
| Chrome拡張機能 | ❌ | ✅ |
| 言語 | 29+ | 100+ |
| 最適な用途 | Developers & creators | Personal reading & accessibility |
1. 音声品質
TTSOpenAI: The voices sound incredibly natural. OpenAI’s deep-learning neural networks produce speech with proper intonation, pauses, and emotion. The six voices — Alloy, Echo, Fable, Onyx, Nova, and Shimmer — each have a distinct personality. Nova sounds young and energetic. Onyx sounds mature and authoritative.
ナチュラルリーダー: The voices are decent but not as lifelike as TTSOpenAI. The premium and plus voices sound better than the free ones. However, many users report that the voices still sound slightly robotic compared to newer AIツール.
2. Pricing Model
TTSOpenAI: The pay-as-you-go model is budget-friendly. You buy credits and use them whenever you want. For 200,000 characters of audio, you spend just $8. There are no monthly commitments or auto-renewals.
ナチュラルリーダー: The subscription model charges $49/month for the Single Plan. That’s $588 per year. Heavy users might find value in unlimited access. But occasional users will overpay compared to credit-based pricing.
💡 Test Result: For our 4-week test generating about 150,000 characters, TTSOpenAI cost $6. The same work on NaturalReader’s Single Plan would have cost $49. TTSOpenAI saved us over 85% on this project.
3. File Format Support
ナチュラルリーダー: This is where NaturalReader truly shines. It reads 20+ file types including PDF, DOCX, EPUB, TXT, and even images through OCR. You can also paste URLs and have web pages read aloud. Few TTS tools match this range.
TTSOpenAI: You can only paste or type text directly into the platform. There is no file upload feature. You cannot drag and drop a PDF or EPUB. For document reading, you need to copy the text manually first.
4. Developer API
TTSOpenAI: The REST API is clean and well documented. Developers can add text to speech features to apps, chatbots, and websites quickly. It supports real-time streaming for low-latency playback. This makes it perfect for voice agents and interactive tools.
ナチュラルリーダー: There is no developer API available. NaturalReader is built for end users only. If you want to build TTS into your own product, this tool cannot help you.
5. 音声クローン
TTSOpenAI: The Custom Voice Maker lets you create a unique voice from a 60-second audio sample. It is not as advanced as イレブンラボ. But it works well for basic voice cloning needs like branding and personalized content.
ナチュラルリーダー: NaturalReader also offers voice cloning. The feature lets you create a voice that sounds like you. This works through their advanced tunes system. Both tools offer voice cloning, but TTSOpenAI’s process is faster.
6. 言語サポート
ナチュラルリーダー: Supports over 100 languages and dialects with 1,000+ voices. This is one of the widest language selections in the TTS market. Great for multilingual content creators and global teams.
TTSOpenAI: Supports 29+ languages including English, Spanish, French, and Japanese. The voices sound natural in supported languages. But the selection is much smaller than NaturalReader’s catalog.
7. Platform Access
ナチュラルリーダー: Available as a web app, mobile app for iOS and Android, and Chrome extension. You can start listening on your phone and continue on your laptop. The cross-platform experience is excellent.
TTSOpenAI: Browser-based only. There is no mobile app and no Chrome extension. You must open the website to use it. Developers can build mobile access through the API, but casual users cannot.
⚠️ Warning: If you need to listen on the go while commuting or exercising, NaturalReader’s mobile app is the clear choice. TTSOpenAI has no offline listening option.
8. Emotion and Expression Control
TTSOpenAI: Offers SSML support for fine-tuning speed, pitch, and pauses. The Story Maker tool adds emotional expression to generated speech. You can make voices sound calm, energetic, or gentle.
ナチュラルリーダー: Offers emotive AI voices and advanced tunes for adjusting pronunciation. You can change reading speed. But the emotion controls are less detailed than TTSOpenAI’s SSML-based customization.
9. Accessibility Features
ナチュラルリーダー: Built for accessibility from the ground up. It supports dyslexia-friendly fonts, text highlighting as it reads, and adjustable speeds up to 900 words per minute. Over 2,000 学校 use it. The OCR scanner reads printed text from your phone camera.
TTSOpenAI: The tool can help visually impaired users consume written content. But it lacks dedicated accessibility features like text highlighting, dyslexia fonts, or a screen reader mode. It is a 音声ジェネレータ first, not a reading aid.
10. Pricing & Cost
Let’s compare the pricing plans side by side.
| プラン | TTSOpenAI | ナチュラルリーダー |
|---|---|---|
| 無料 | 2,000 chars | Basic voices + 20 min/day premium |
| Entry Paid | $8 / 200K chars | $49/month (Single Plan) |
| チーム | 該当なし | $79/month (Team Plan) |
| Commercial Use | ✅ Included | Separate commercial license needed |
TTSOpenAI: The pay-as-you-go model wins for most users. You never waste money on unused capacity. Commercial use is included in every credit purchase. No separate license needed.
ナチュラルリーダー: The $49/month subscription makes sense for heavy daily readers. But you need a separate commercial license to share audio publicly. The personal version audio is strictly for your own listening.
Different Scenarios
| If You Need… | Choose | Why |
|---|---|---|
| Tight budget | TTSOpenAI | Pay only for what you use |
| Read PDFs and ebooks | ナチュラルリーダー | 20+ file format support |
| Build voice into your app | TTSOpenAI | Full REST API included |
| Listen on mobile | ナチュラルリーダー | iOS and Android apps |
| Best voice quality | TTSOpenAI | OpenAI’s neural voices |
| 100+ languages | ナチュラルリーダー | 1,000+ multilingual voices |
| Accessibility needs | ナチュラルリーダー | Dyslexia-friendly features |
💰 Your Budget
TTSOpenAI’s pay-as-you-go model is cheaper for most users. NaturalReader’s $49/month only makes sense if you use it every single day for hours.
🔌 Your Tech Stack
Developers should pick TTSOpenAI for its REST API. NaturalReader has no API and works only through its own apps and browser extension.
📝 Your Content Type
If you need to read documents and ebooks, NaturalReader wins. If you need to create voiceovers and audio content, TTSOpenAI is the better tool.
🎓 Your Experience Level
Both tools are beginner-friendly. NaturalReader is easier for non-technical users. TTSOpenAI is simple too, but the API features are aimed at developers.
🆓 Free Trials and Demos
NaturalReader offers unlimited basic voices for free. TTSOpenAI gives 2,000 free characters. Test both before spending any money.
🛟 Support Options
NaturalReader offers email support and a help center. TTSOpenAI relies on documentation and community forums. Neither tool is known for fast responses.
Switching Guide
Already using one of these tools? Here’s what to expect if you switch.
🔄 Switching from NaturalReader to TTSOpenAI?
✅ What you’ll gain:
- More realistic voices powered by OpenAI’s engine
- Flexible pay-as-you-go pricing with no monthly fees
- A developer API for building voice features into your apps
❌ What you’ll lose:
- PDF, DOCX, and EPUB file reading support
- Mobile app and Chrome extension for listening on the go
- 1,000+ voice options in 100+ languages
📋 How to switch:
- Cancel your NaturalReader subscription and request a refund if eligible
- Create a free TTSOpenAI account and test the 2,000 free characters
- Buy a credit pack and start generating audio from your text
🔄 Switching from TTSOpenAI to NaturalReader?
✅ What you’ll gain:
- Support for 20+ file types including PDF, DOCX, and EPUB
- Mobile app and Chrome extension for listening anywhere
- 1,000+ voices across 100+ languages and dialects
❌ What you’ll lose:
- Ultra-realistic OpenAI voice quality
- Flexible pay-as-you-go pricing with no subscription
- Developer REST API for building voice into your apps
📋 How to switch:
- Use remaining TTSOpenAI credits before they expire in 60 days
- Sign up for NaturalReader’s free plan and test the voices
- Upgrade to the Single Plan when ready for full premium access
最終評決
| カテゴリ | 勝者 |
|---|---|
| 💰 Pricing | TTSOpenAI |
| 🎯 Voice Quality | TTSOpenAI |
| 📁 File Support | ナチュラルリーダー |
| 🔌 Developer API | TTSOpenAI |
| 📱 Platform Access | ナチュラルリーダー |
| 🌍 Language Selection | ナチュラルリーダー |
| 🎭 Emotion Control | TTSOpenAI |
| ♿ Accessibility | ナチュラルリーダー |
| 🏆 Overall Winner | TTSOpenAI |
🏆 WINNER: TTSOpenAI
TTSOpenAI wins 4 out of 8 categories with a tie-breaking edge on value.
Best for: Content creators, developers, voiceover projects, and anyone who wants realistic AI voices without a monthly subscription.
TTSOpenAI and NaturalReader serve very different audiences.
TTSOpenAI is a 音声ジェネレータ built for creating professional audio content.
NaturalReader is a reading tool built for consuming documents and ebooks aloud.
NaturalReader is excellent for students, accessibility needs, and document reading.
However, if you need realistic voices at a flexible price, TTSOpenAI is the better choice.
Now, go out and bring your text to life!
More of NaturalReader Compared
Here’s how NaturalReader stacks up against other competitors:
NaturalReader vs マーフAI
NaturalReader wins on: File format support, cross-platform access
Murf AI wins on: Studio-quality voices, video sync tools
NaturalReader wins on: More voices and languages, lower price
Speechify wins on: Voice quality, mobile experience
NaturalReader vs 説明
NaturalReader wins on: Document reading, accessibility features
Descript wins on: Audio and video editing, transcription
NaturalReader wins on: File support, price for basic use
ElevenLabs wins on: Voice realism, voice cloning depth
NaturalReader vs Play.ht
NaturalReader wins on: Document reading, OCR scanning
Play.ht wins on: Voice variety, podcast creation
NaturalReader wins on: File format range, accessibility
ロボ wins on: Video voiceover tools, emotion control
NaturalReader wins on: Cross-platform apps, document support
リスト番号 wins on: Podcast hosting, audio article embeds
NaturalReader vs ポッドキャスト
NaturalReader wins on: File reading, language variety
Podcastle wins on: Podcast editing suite, recording tools
NaturalReader vs ダプダブ
NaturalReader wins on: Proven track record, file support
Dupdub wins on: AIアバター creation, video dubbing
NaturalReader vs WellSaid Labs
NaturalReader wins on: Price, file reading features
ウェルサイドラボ wins on: Enterprise voice quality, brand voices
NaturalReader vs リボイス
NaturalReader wins on: Platform access, accessibility tools
Revoicer wins on: One-time pricing, emotion control
NaturalReader wins on: Consumer pricing, mobile app
リードスピーカー wins on: Enterprise integrations, compliance
NaturalReader vs 改変
NaturalReader wins on: Document reading, free plan
Altered wins on: Voice transformation, dubbing tools
NaturalReader vs スピーチロ
NaturalReader wins on: Voice variety, cross-platform use
Speechelo wins on: One-time payment model, simplicity
NaturalReader vs ヒューム
NaturalReader wins on: Document reading, consumer focus
Hume wins on: Emotion AI research, empathic voice
More of TTSOpenAI Compared
Here’s how TTSOpenAI stacks up against other competitors:
TTSOpenAI wins on: Voice realism, flexible pricing
Murf wins on: Video sync tools, studio editing
TTSOpenAI wins on: Price, developer API
Speechify wins on: Mobile app, reading features
TTSOpenAI wins on: Voice quality, simpler pricing
Descript wins on: Full audio/video editing suite
TTSOpenAI wins on: Price, no subscription required
ElevenLabs wins on: Voice cloning, 1,200+ voices
TTSOpenAI vs Play.ht
TTSOpenAI wins on: Voice realism, API simplicity
Play.ht wins on: More languages, podcast tools
TTSOpenAI vs Lovo
TTSOpenAI wins on: Pricing flexibility, voice quality
Lovo wins on: Video voiceover workflow, emotion range
TTSOpenAI wins on: Voice realism, pay-as-you-go model
Listnr wins on: Podcast hosting, audio article embeds
TTSOpenAI wins on: Voice quality, developer API
Podcastle wins on: Podcast production, recording tools
TTSOpenAI wins on: Voice realism, pricing
Dupdub wins on: AIアバター videos, dubbing features
TTSOpenAI wins on: Price, no minimum commitment
WellSaid Labs wins on: Enterprise features, custom brand voices
TTSOpenAI vs Revoicer
TTSOpenAI wins on: Voice quality, API access
Revoicer wins on: One-time pricing, emotion voices
TTSOpenAI wins on: Price, ease of use
ReadSpeaker wins on: Enterprise compliance, on-premise
TTSOpenAI vs Altered
TTSOpenAI wins on: Voice naturalness, flexible pricing
Altered wins on: Voice transformation, dubbing workflow
TTSOpenAI vs Speechelo
TTSOpenAI wins on: Voice quality, API for developers
Speechelo wins on: One-time payment, beginner simplicity
TTSOpenAI vs Hume
TTSOpenAI wins on: Consumer pricing, ease of use
Hume wins on: Emotion AI research, empathic voices
よくある質問
Can I use NaturalReader for free?
Yes. NaturalReader has a free version with unlimited basic voices. You also get 20 minutes per day of premium voices. The free plan requires internet connectivity.
Is TTSOpenAI free to use?
Yes. TTSOpenAI offers 2,000 free characters to test all voices. No credit card is needed to start. After the free tier, you buy credits with the pay-as-you-go model.
What is the most realistic AI text to speech?
ElevenLabs is widely considered the most realistic AI TTS tool in 2026. TTSOpenAI comes very close, especially for the price. Both use deep-learning neural networks for natural sounding speech.
Is NaturalReader better than Speechify?
NaturalReader offers more voices and wider file format support. Speechify has better voice quality and a smoother mobile experience. Your choice depends on whether you need document reading or premium audio quality.
Does OpenAI have a text to speech service?
Yes. OpenAI offers text to speech through its API. TTSOpenAI is a platform built on top of OpenAI’s voice engine technology. It makes OpenAI’s TTS accessible through a simple browser interface.
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