DeepL vs Local AI: Which Engine Should I Use?

Comprehensive comparison of MAITO's DeepL and Local AI translation engines to help you choose the right one for your needs

Pangaia Software 10 min read

MAITO offers two translation engines: DeepL Cloud Translation and Local AI Translation. This guide helps you understand the differences and choose the right one for each task.

Quick Comparison

FeatureDeepL CloudLocal AI
Translation QualityExcellent (professional-grade)Very Good (general use)
PrivacyData sent to cloud100% private - nothing leaves PC
Internet RequiredYesNo - works completely offline
Cost€4.99/mo + usage or 500K free chars/moFree
SetupAPI keyDownload 2-8GB model
SpeedConsistently fastDepends on your hardware
Text Translation✅ Up to 130,000 chars✅ Unlimited (intelligent chunking)
Document Translation✅ DOCX, PDF, PPTX, HTML, TXT❌ Not yet (text extraction possible)
Website Translation✅ Full support❌ Not yet (copy-paste works)
Formality Control✅ Formal/Informal/Default❌ Neutral tone only
Languages30+ languages32 languages
Streaming❌ All-at-once results✅ Word-by-word streaming
Performance Metrics✅ Tokens/sec, time estimates

Best Approach

Configure both engines and switch based on your needs! Most users use Local AI 80% of the time for privacy and zero cost, switching to DeepL for documents or when they need the highest quality.

Translation Quality Comparison

DeepL Quality

Strengths:

  • Industry-leading translation accuracy
  • Excellent handling of idioms and context
  • Professional-grade output for publications
  • Consistently polished phrasing
  • Great with technical and specialized content

Best For:

  • Business documents
  • Marketing materials
  • Content for publication
  • Legal documents
  • Academic papers
  • Official correspondence

Example (English → German):

  • Source: “The meeting was productive, and we made significant progress.”
  • DeepL: “Das Treffen war produktiv, und wir haben bedeutende Fortschritte gemacht.”
  • Quality: Near-perfect, publication-ready

Local AI Quality

Strengths:

  • Very good translation accuracy for general use
  • Understands context well
  • Natural-sounding output
  • Excellent for comprehension
  • Good with everyday language

Considerations:

  • Occasionally less polished phrasing than DeepL
  • May need review for published content
  • Best for understanding, not always for publishing as-is

Best For:

  • Reading foreign content
  • Email comprehension
  • Chat messages
  • Personal documents
  • Quick translations
  • Sensitive/confidential content

Example (English → German):

  • Source: “The meeting was productive, and we made significant progress.”
  • Local AI: “Das Treffen war produktiv und wir machten bedeutende Fortschritte.”
  • Quality: Very good, understandable, slightly different phrasing

Quality Gap Closing

Local AI models improve constantly. Rosetta models are specifically optimized for translation, providing quality that’s excellent for most use cases even if not quite matching DeepL’s polish.

Privacy and Security

DeepL Privacy

How It Works:

  • Your text is sent to DeepL’s servers in Germany
  • Processed on their infrastructure
  • Translation returned to you
  • DeepL stores data temporarily for processing

DeepL’s Privacy Commitments:

  • GDPR compliant
  • ISO 27001 certified
  • Data encrypted in transit
  • No data used for training (Pro plan)
  • Servers in EU

Good For:

  • Non-confidential content
  • Users comfortable with cloud processing
  • Organizations with approved vendor lists

Not Ideal For:

  • Highly confidential documents
  • Sensitive personal information
  • Strict data sovereignty requirements
  • Classified information

Local AI Privacy

How It Works:

  • Everything happens on your computer
  • No internet connection used for translation
  • Nothing sent to any server
  • Translation model runs locally

Privacy Benefits:

  • 100% private - no external access
  • Perfect for confidential content
  • Complete data sovereignty
  • No third-party involvement
  • Can work fully offline

Perfect For:

  • Confidential business documents
  • Medical/legal records
  • Personal sensitive information
  • GDPR-strict environments
  • Classified content
  • Any privacy-critical use case

Privacy Champion

If privacy is your primary concern, Local AI is unmatched. Your data never leaves your computer, period. Want to verify this yourself? Check out How to Verify MAITO Doesn’t Send Data - a beginner-friendly guide to monitoring network connections.

Cost Comparison

DeepL Costs

Free Plan:

  • Cost: €0/month
  • Limit: 500,000 characters/month
  • Overage: Access pauses until next month
  • Best For: Light users, occasional translations

Pro Plan:

  • Base: €4.99/month
  • Usage: €0.00002 per character (~€20 per million)
  • Limit: Based on budget
  • Best For: Heavy users, businesses

Example Costs (Pro Plan):

  • 10,000 chars (2-3 pages): €0.20
  • 50,000 chars (10-15 pages): €1.00
  • 250,000 chars (50-75 pages): €5.00
  • 1 million chars (200+ pages): €20.00

Local AI Costs

One-Time Costs:

  • Model Download: Free (2-8GB bandwidth)
  • Setup Time: 5-10 minutes

Ongoing Costs:

  • Per Translation: €0.00
  • Monthly Fee: €0.00
  • Character Limits: Unlimited (after setup)

Only Cost: Electricity to run your computer (negligible)

Cost Winner

For heavy users, Local AI pays for itself immediately. Translate millions of characters at zero cost after the initial model download.

Performance and Speed

DeepL Performance

Characteristics:

  • Consistently fast regardless of your hardware
  • Powered by cloud servers
  • Typical response: 2-5 seconds for most texts
  • No variability based on your system

Dependent On:

  • Internet connection speed
  • DeepL server load (minimal variation)

Best For:

  • Users with older/slower computers
  • When consistency is critical
  • Quick translations needed

Local AI Performance

Characteristics:

  • Highly variable based on YOUR hardware
  • Fast on modern systems (10-20 tokens/sec)
  • Slower on older systems (2-5 tokens/sec)
  • Streaming output (see progress in real-time)

Performance Factors:

  • CPU speed and generation
  • Available RAM (8GB+ recommended)
  • GPU availability (for DML models)
  • System load (other apps running)

Typical Speeds:

  • High-end desktop (i7/Ryzen 7, 16GB, GPU): 15-25 tokens/sec
  • Mid-range laptop (i5/Ryzen 5, 8GB): 8-12 tokens/sec
  • Entry-level (i3, 4GB): 2-5 tokens/sec

What's Acceptable?

10+ tokens/sec feels responsive for most users. A 200-word paragraph translates in 20-30 seconds, which is fast enough for everyday use.

Feature Differences

Document Translation

DeepL:

✅ DOCX, PDF, PPTX, HTML, TXT

✅ Preserves formatting and layout

✅ Images and structure maintained

✅ Up to 10MB files

Local AI:

❌ Not currently supported

⚠️ Workaround: Drag-drop to extract text

🔜 Coming in future updates

Winner: DeepL (for now)

Formality Control

DeepL:

✅ Formal, Informal, Default options

✅ Language-specific (German Sie/du, Japanese keigo, etc.)

✅ Great for business vs casual content

Local AI:

❌ Neutral tone only

❌ No formality adjustment

Winner: DeepL

Streaming Translation

DeepL:

❌ Returns complete translation at once

❌ No incremental progress

❌ Wait for entire result

Local AI:

✅ Word-by-word streaming

✅ See translation as it’s generated

✅ Progress percentage shown

✅ Can cancel mid-translation

Winner: Local AI (for user experience)

Text Length Handling

DeepL:

  • Up to 130,000 characters per request
  • Entire books can be translated at once
  • Single-request translation

Local AI:

  • Unlimited text length
  • Intelligent chunking at sentence/paragraph boundaries
  • Completely transparent to users (seamless experience)

Winner: Both work well for any text length

Use Case Recommendations

Use DeepL When:

Translating documents (DOCX, PDF, PPTX)

  • Only DeepL supports formatted documents currently
  • Essential for business/academic documents

Professional/published content

  • Highest quality output
  • Marketing materials, websites, official docs

Need formality control

  • Business communications requiring formal tone
  • Language pairs with strong formal/informal distinction

Your computer is slow

  • DeepL performance independent of your hardware
  • Consistent speed for everyone

Single-request processing

  • Processes entire text in one request (no chunking)
  • Slightly simpler internal processing

Use Local AI When:

Privacy is critical

  • Confidential business information
  • Sensitive personal data
  • Classified content
  • GDPR-strict requirements

Working offline

  • On planes, trains, remote locations
  • Poor/no internet connectivity
  • Want guaranteed availability

Translating frequently

  • Zero per-translation cost
  • Unlimited usage
  • Heavy daily translation needs

Quick personal translations

  • Emails, chat messages, social media
  • General understanding needed
  • Not for publication

Budget constraints

  • No monthly fees
  • No per-character costs
  • Free after model download

Real-World Scenarios

Scenario 1: Business Email from Foreign Client

Situation: Received important email from Japanese client.

Recommendation: Local AI

  • Why: Email likely contains business details (privacy matters)
  • Quality: More than sufficient to understand content
  • Cost: Free
  • Speed: Fast enough for email
  • Alternative: DeepL if need to quote/reply using exact translation

Scenario 2: Contract Translation

Situation: Need to translate 20-page contract from German to English.

Recommendation: DeepL

  • Why: Professional quality critical for legal documents
  • Document: PDF with formatting to preserve
  • Formality: Formal tone appropriate
  • Review: Still needs legal review, but better starting point

Scenario 3: Daily News Reading

Situation: Read foreign news daily for research.

Recommendation: Local AI

  • Why: Privacy (don’t share reading habits)
  • Cost: Free for unlimited daily reading
  • Quality: Sufficient for comprehension
  • Speed: Fast enough on mid-range systems

Scenario 4: Marketing Brochure

Situation: Translate company brochure for international clients.

Recommendation: DeepL + Human Review

  • Why: Publication quality critical
  • Documents: PPTX with formatting
  • Formality: Professional tone needed
  • Quality: Highest possible, then human polish

Scenario 5: Personal Travel Diary

Situation: Translate personal diary entries while traveling.

Recommendation: Local AI

  • Why: Private content
  • Offline: Works on plane/train
  • Cost: Free for unlimited entries
  • Quality: Personal use, not publication

Can I Use Both?

Absolutely! And you should.

Hybrid Strategy

Many MAITO users follow this pattern:

80% of translations: Local AI

  • Daily emails
  • Quick translations
  • Personal content
  • Reading comprehension
  • Social media
  • Chatting

20% of translations: DeepL

  • Business documents
  • Content for publication
  • Client-facing materials
  • Official correspondence
  • When highest quality needed

Switching is Easy

  1. Open Settings → Translation tab
  2. Select desired engine
  3. Click Apply
  4. Switch takes effect immediately

See switching guide

Best Practice

Start with Local AI as your default. Switch to DeepL when you need document support or professional quality. This maximizes privacy while ensuring quality when it matters.

What’s Next?

Learn more:

Summary

DeepL: Best quality, documents, formality, consistent speed - but costs money and requires internet Local AI: Complete privacy, offline, zero cost, unlimited - but quality slightly lower and speed varies by hardware

The Smart Choice: Configure both, use Local AI by default, switch to DeepL when you need its specific advantages!

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