← Speech-to-Text
AssemblyAI
Universal-3.5 Pro
Measured 2026-07-03
Run Universal-3.5 Pro on Speko →One API, every model on this board.
WER · batch
2.0%
WER · streaming
Read speech
3.73%
Conversation
14.54%
Details
Read speech
n=1541 · FLEURS test+dev+train · vendor-direct
Conversation
12.4–16.9% · EdAcc n=283 · 60 speakers, 2 passes, 2026-10-01
Deletions carry most of it: 7.1% dropped words against 5.8% substitutions.
Finalize
408ms
p50–p90 · US East · n=200 · vendor-direct · ±12%
Time to first token
1.01s
p50–p90 · US East · n=200 · vendor-direct · ±10%
Cost / min
$0.0075
Universal-3.5 Pro Realtime at $0.45/hr. Async pre-recorded is $0.0035. Diarization and other add-ons bill on top.
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URL
https://speko.ai/benchmarks/stt/assemblyai-universal-3-5-pro