Context window calculator
Paste your prompt and set expected output to see what percentage of each model context window you use, and how much room remains.
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.
What is a context window?
The context window is the maximum number of tokens a model can consider at once, covering your system prompt, conversation history, retrieved context and the generated output. Exceed it and the oldest tokens are dropped or the request is rejected.
FAQ
How big are current context windows?
They range from 8K tokens on older models to 1 million or more on the largest current ones. Bigger windows fit more context but cost more per request, since you are billed for every token you send.
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.