Prompt context window calculator
Enter your prompt and expected output tokens to check them against every model context window and avoid truncation.
Token count uses the exact GPT (o200k) tokenizer. Counted in your browser, never uploaded.
| Model | Tokens | Per request | Monthly | Context |
|---|---|---|---|---|
| Qwen3.8 Max | 0 est. | $0.0030 | $3.00 | 0.1% |
| DeepSeek V4 Flashcheapest | 0 est. | $0.00014 | $0.14 | 0.1% |
| Claude Opus 5 | 0 est. | $0.013 | $12.50 | 0.1% |
Token counts vary by tokenizer and model; non-OpenAI counts are estimates. Cost is an estimate and provider pricing can change. See each model's source on the pricing page.
Plan the prompt and the answer together
A common mistake is sizing only the prompt and forgetting the model needs room to answer within the same window. Budget both: if the window is 128K and you expect a 4K-token answer, keep the prompt under about 124K. This tool shows the split for every model at once.
FAQ
Does the model output count against the context window?
Yes. Input and output share the same window, so you must leave room for the response or the request fails or truncates.
Current model pricing
| Model | Provider | Input | Cached | Output | Context | Verified |
|---|---|---|---|---|---|---|
| Qwen3.8 Max | Alibaba | $2 | $0.25 | $6 | 1 000k | 2026-08-03 |
| Claude Haiku 4.5 (latest) | Anthropic | $1 | $0.1 | $5 | 200k | 2025-10-15 |
| Claude Opus 4.8 | Anthropic | $5 | $0.5 | $25 | 1 000k | 2026-05-28 |
| Claude Sonnet 4.6 | Anthropic | $3 | $0.3 | $15 | 1 000k | 2026-03-13 |
| DeepSeek Chat | DeepSeek | $0.14 | $0.0028 | $0.28 | 1 000k | 2026-02-28 |
| Gemini 2.5 Flash | $0.3 | $0.03 | $2.5 | 1 048,576k | 2025-06-17 | |
| Gemini 3.5 Flash | $1.5 | $0.15 | $9 | 1 048,576k | 2026-05-19 | |
| Mistral Medium (latest) | Mistral | $1.5 | n/a | $7.5 | 262,144k | 2026-04-29 |
| Kimi K3 | Moonshot AI | $3 | $0.3 | $15 | 1 048,576k | 2026-07-16 |
| GPT-4.1 mini | OpenAI | $0.4 | $0.1 | $1.6 | 1 047,576k | 2025-04-14 |
| GPT-4o | OpenAI | $2.5 | $1.25 | $10 | 128k | 2024-08-06 |
| GPT-5.5 | OpenAI | $5 | $0.5 | $30 | 1 050k | 2026-04-23 |
| Grok 4.5 | xAI | $2 | $0.3 | $6 | 500k | 2026-07-08 |
| GLM-5.2 | Zhipu AI | $1.4 | $0.26 | $4.4 | 1 000k | 2026-06-13 |
Prices per 1M tokens (USD). Each model links to its official source. Seed values pending re-verification. See the methodology.