LLM Consistency Tester
Paste N outputs — measure variance, similarity, stability
Workflow: Run your prompt 3-10× at your chosen temperature. Paste each output below. We measure the variance across them.
📚 Learn more — how it works, FAQ & guide Click to expand
Learn more — how it works, FAQ & guide
Click to expand
LLM consistency tester
Measure LLM output variance. Jaccard, cosine, stability score across N runs.
How to use this tool
- 1
Run your prompt 3-10 times
Same prompt, any model, save the outputs.
- 2
Paste them below
One output per text area. Use the + button to add more.
- 3
See consistency metrics
Length variance, Jaccard similarity, cosine, stability score.
Frequently Asked Questions
Why test LLM consistency?
For production LLMs, variance is a killer. A prompt that works 9/10 times but fails the 10th is production-fragile. Teams need to know: is the variance acceptable? Should I lower temperature? Is this task fundamentally non-deterministic?
What is Jaccard similarity?
Jaccard = |A ∩ B| / |A ∪ B| for word sets. Value 1.0 = identical words, 0 = no shared words. For most LLM outputs, 0.3-0.6 = semantically similar with different wording, 0.7+ = very close phrasing.
How to improve consistency?
Lower temperature (0.0-0.3 for deterministic tasks). Add more few-shot examples. Use structured output (JSON schema). Pick a lower-creativity model. For truly deterministic tasks consider fine-tuning.
You might also like
🔒
100% Privacy. This tool runs entirely in your browser. Your data is never uploaded to any server.