AI Prompt Token Counter & Cost Calculator

Prompt Token Counter & AI Cost Calculator

Paste your prompt, pick a model, and see input tokens, output tokens, and estimated API cost. This tool covers GPT-4o, GPT-4 Turbo, Claude 3.5, Claude 3 Haiku, and Gemini 1.5 models so you can compare pricing before you ship.

How token pricing works

- Models charge separately for input tokens (your prompt) and output tokens (the reply).

- Pricing is published per 1,000 tokens (not per request). For example, GPT-4o is about $0.005 per 1,000 input tokens and $0.015 per 1,000 output tokens.- Token count is roughly characters / 4. A 100-word prompt is usually 120–160 tokens.
- Longer replies cost more. An expected 800-token answer can cost 5x a short 150-token reply.

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What this calculator shows

- Input tokens: Approximate tokens in your prompt using 1 token ≈ 4 characters.

- Output tokens: What you expect back (defaults to 150 if left blank).
- Cost per run: Input + output token cost for the selected model.
- Cost per 1,000 runs: Easy budgeting for production usage.
- Model price table: Quick comparison of input vs output rates across vendors.

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Practical examples

- Short customer reply (90-word prompt, 120-token reply) on GPT-4o → around $0.003 per run.

- Long knowledge-base rewrite (600-word prompt, 700-token reply) on Claude 3.5 Sonnet → around $0.14 per run.
- High-volume notifications (30-word prompt, 60-token reply) on GPT-4o Mini → a fraction of a cent per run and <$4 per 1,000 runs.

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Tips to reduce cost

- Trim prompts: Remove redundant instructions and keep few-shot examples minimal.

- Cap max tokens: Set `max_tokens` to a sensible ceiling to avoid runaway costs.
- Choose the right tier: GPT-4o Mini or Claude Haiku are far cheaper for short tasks.
- Cache system prompts: Reuse shared context in your app to shrink each request.
- Monitor output length: Long-form generations dominate cost; keep answers scoped.

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Assumptions and accuracy

- Token estimates use a simple 1 token ≈ 4 characters heuristic. Real tokenizers vary by model; actual bills may differ by ~5–10%.

- Pricing is based on public rate cards from OpenAI, Anthropic, and Google as of January 2026. Always verify before deploying to production.
- We do not send your text anywhere. Everything runs client-side for quick estimates.

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Related AI pricing tools

- GPT-4o vs Claude cost comparison

- Monthly AI API spend estimator
- Input vs output token split visualizer (coming soon)

If you need a custom variant (per-user cost, per-conversation budgeting, or batch processing), reach out and we’ll add it.