Prompt cost diff
Shorter prompts save money at scale. Paste two variants and see the token delta and dollar difference per model — per call and per month.
Variant A
Variant B
Calls per month
Shareable in the URL. Prompt text stays local — never synced.
Token delta
Paste both variants to compare costs.
Cost comparison
Input tokens only ( pricing). Sorted by biggest monthly savings first.
| Model | Cost A | Cost B | Per call | Per month |
|---|---|---|---|---|
| · |
Prompt text never leaves your browser. Costs assume every call sends the full prompt as input — no caching, no output tokens.
About this tool
A 200-token system prompt difference sounds tiny until you multiply it by ten million support tickets. This diff shows where trimming instructions, dropping redundant examples, or moving static text to a cache layer pays off.
Token counts use the same chars÷4 heuristic as our other LLM calculators. For production billing, measure with the vendor tokenizer — especially for code and non-English text.