Prompt Token Budget Calculator
Budget system, example and user tokens against a model.
With the default inputs, 800 tokens in your prompt — $0.00100 per call · 127,200 tokens left in the context window. Enter your own numbers below to recompute instantly; the full step-by-step math is shown under the worked example.
Results update automatically as you type.
- System prompt
- 500 tokens
- Examples
- 0 tokens
- User message
- 300 tokens
- Total input
- 800 tokens
- Input cost / call
- $0.00100
- Context remaining
- 127,200 tokens
Plan your prompt token budget. Split tokens across system prompt, few-shot examples and the user message to see total input, cost per call, and how much context window is left.
How this is calculated
We split your input into system, example and user tokens, sum them for total input, price that at your model's input rate, and show how much of the context window is left for output. It's a way to see the cost of each part of a prompt before you ship it.
Is this a good result? What to do next
The system prompt and examples are re-sent on every call, so they dominate cost at scale even when they feel small. If they're a large share of the budget, caching or trimming them pays back on every request.
Typical planning ranges
- System prompt
- re-sent every call (cache candidate)
- Examples
- multiply input on every request
- Healthy split
- keep fixed overhead small vs the user message
Ranges are typical planning figures to sanity-check your result, not authoritative benchmarks. Your numbers will vary with use case, volume, and vendor.
How to improve this number
- Trim the system prompt to the minimum that stays reliable.
- Cache stable system/example blocks where supported.
- Replace many few-shot examples with fine-tuning at high volume.
Common mistakes
- Treating a big system prompt as free because it's written once.
- Ignoring that examples scale cost linearly with volume.
When to use a different approach
To value examples specifically, use the few-shot prompt cost calculator. To see caching savings, use the prompt caching savings calculator.
Worked example (defaults)
With the default inputs above, here is the result:
- System prompt
- 500 tokens
- Examples
- 0 tokens
- User message
- 300 tokens
- Total input
- 800 tokens
- Input cost / call
- $0.00100
- Context remaining
- 127,200 tokens
Sources & references
Frequently asked questions
How big should my system prompt be?+
As small as possible while staying reliable. Every token is re-sent on each call, so trimming the system prompt lowers cost at scale — or cache it.
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