2025 Accuracy Leaders at a Glance

Top Performers:

• Whisper Large-v3: 97.9% word accuracy (MLPerf benchmark)
• Deepgram Nova-3: 96% average accuracy
• 95-99% in optimal conditions
• 69+ languages, industry-specific vocabulary

Key Metrics:

• Best WER: 5.63% (Canary Qwen 2.5B)
• Edge Models: 8.18% WER (Granite-Speech)
• 82-94% accuracy typical
• Clean Audio: 93-99% achievable

Understanding Word Error Rate (WER)

What is WER?

Word Error Rate (WER) is the industry-standard metric for measuring transcription accuracy. It calculates the minimum number of word-level edits (substitutions, deletions, and insertions) required to transform the transcription into the reference text.

WER = (Substitutions + Deletions + Insertions) / Total Words

WER vs Accuracy

5%WER = 95% accuracy (excellent)
10%WER = 90% accuracy (good)
15%WER = 85% accuracy (acceptable)
20%+WER = 80% or lower (needs improvement)

2025 Transcription Accuracy Benchmarks

Tool	Clean Audio	Real-World Meeting	Noisy Environment	WER Range	Languages
OpenAI Whisper Large-v3	97.9%	88-93%	74-83%	2.1-8.1%	99+
Deepgram Nova-3	98%	94%	83%	4.8-7%	36+
Otter.ai	92-94%	82-85%	71-78%	6-29%	English only
Fireflies.ai	94%+	88-92%	80-85%	6-12%	69+
Distil-Whisper	96%	85-90%	75-82%	14.9%	99+
Sonix	95-99%	89.6%	82%	5-10%	49+
Canary Qwen 2.5B	94.4%	88%	78%	5.63%	Multi
Granite-Speech-3.3	91.8%	85%	75%	8.18%	Multi

MLPerf 2025 benchmarks, Interspeech 2023/2025, Hugging Face Open ASR Leaderboard, independent testing reports.

Accuracy by Use Case

Medical & Legal (High Stakes)

• Required accuracy: 97%+ or human review
• Best performer: Whisper: 96.8% medical, 97.3% legal
• 94.2% medical conferences
• Use with human verification for compliance

Sales & CRM Integration

• Required accuracy: 85-90% typically sufficient
• Best performer: Fireflies with CRM automation
• Key features: Action items, sentiment analysis
• Prioritize integrations over raw accuracy

Team Collaboration

• Required accuracy: 80-85% for meeting notes
• Best performer: Otter.ai with real-time editing
• Key features: Live collaboration, sharing
• Choose tools with easy correction workflows

Multilingual Meetings

• 15-20% accuracy drop for non-native speakers
• Best performer: Whisper for language coverage
• 69+ languages with custom vocabulary
• Otter only supports English

How Accuracy is Tested

Standard Benchmarks

1 Clean audiobook recordings, gold standard for ASR
2AMI Corpus: Real meeting recordings with multiple speakers
3 Industry-standard ML benchmark (2025 update)
4 Academic research benchmarks

Real-World Testing Factors

AAudio quality: Compression, bitrate, sample rate
BSpeaker characteristics: Accent, speed, overlap
C Background noise, echo, reverb
D Technical terms, proper nouns, numbers

Marketing Claims vs Reality

Many tools claim 95-99% accuracy, but this typically applies only to optimal conditions: single native English speaker, professional microphone, quiet studio environment. Real-world meeting accuracy is typically 15-20% lower. Independent testing showed Sonix's 99% claim translated to 89.6% in actual tests.

What Affects Transcription Accuracy

Accuracy Killers

• Multiple speaker overlap: -25-40%
• Poor microphone: -15-25%
• Technical jargon: -15-25%
• Background noise: -8-12% per 10dB
• Non-native speakers: -15-20%
• -30-50%

Accuracy Boosters

• Headset microphone: +20% vs laptop mic
• Clear pronunciation: +10-15%
• Quiet environment: +15-20%
• Optimal pace: 140-180 words/minute
• Custom vocabulary: +5-15%
• Native speaker: +15-20%

Model Trade-offs

• Whisper Large-v3: Best accuracy, slowest
• Whisper Turbo: 6x faster, -1-2% accuracy
• 6x faster, -1% accuracy
• Edge models: Real-time, variable accuracy
• Cloud APIs: Optimized for latency

Our Recommendations

Best Overall Accuracy

OpenAI Whisper Large-v3

97.9% word accuracy on MLPerf benchmark. Best for developers who can self-host or use API.

$0.006/minute via API

Best for: Technical users, high-volume processing

Requires development setup ($5K-15K)

Best for Business Meetings

Fireflies.ai

Excellent accuracy with CRM integration, sentiment analysis, and action item extraction.

Free tier available, Pro from $10/mo

Best for: Sales teams, business meetings

Learn More →

Best for Collaboration

Otter.ai

Real-time transcription with live editing and team collaboration features.

600 free minutes/month

Best for: Teams, note sharing