Context window checker
Check a document, codebase or chat against each model's window.
0tokens to fit, answer included paste a document or type a size
Fits: under 75% of the window. Tight: 75 to 100%. Too long: split the document, and the tool says into how many parts. The answer must also stay under the model's maximum output.
Prices and limits checked on October 26, 2026 on each provider's own page. See the numbers and sources
The numbers behind this tool
Read on October 26, 2026 from each provider's own page. Prices are US dollars per million tokens, standard tier.
| Model | API id | Input | Cached input | Output | Context window | Max output | Source |
|---|---|---|---|---|---|---|---|
| GPT-6 Astra OpenAI | gpt-6-astra |
$10.00 | $1.00 | $50.00 | 1,050,000 | 128,000 | developers.openai.com |
| Flagship ('Our most capable model'). Prices for <=272K input tokens; above 272K: $20.00 in / $2.00 cached / $75.00 out. Context stated as '1.05M', max output as '128K tokens'. Context/max output from developers.openai.com/api/docs/models. | |||||||
| GPT-6.1 Sol OpenAI | gpt-6.1-sol |
$2.00 | $0.10 | $10.00 | 1,050,000 | 128,000 | developers.openai.com |
| Mid option ('Near-Astra performance for complex work at a lower cost'). Above 272K input: $4.00 / $0.20 / $15.00. Context stated as '1.05M', max output '128K tokens'. | |||||||
| GPT-6 Luna OpenAI | gpt-6-luna |
$0.10 | $0.01 | $0.50 | 1,050,000 | 128,000 | developers.openai.com |
| Small ('Our most efficient model for focused, high-volume tasks'). Above 272K input: $0.20 / $0.02 / $0.75. Context stated as '1.05M', max output '128K tokens'. | |||||||
| Claude Fable 5.1 Anthropic | claude-fable-5-1 |
$10.00 | $0.25 | $50.00 | 1,000,000 | 128,000 | platform.claude.com |
| Top model ('demanding reasoning and long-horizon agentic work'). Cached = cache hits/refreshes (0.025x input); 5m cache write $12.50, 1h write $20. Full 1M context at standard pricing. Context stated as '1M tokens', max output '128K tokens'. Claude Mythos 5.1 has the same prices but limited availability. Context/ID from platform.claude.com/docs/en/about-claude/models/overview. | |||||||
| Claude Opus 5.5 Anthropic | claude-opus-5-5 |
$4.00 | $0.20 | $20.00 | 1,000,000 | 128,000 | platform.claude.com |
| Anthropic's recommended default ('start with Claude Opus 5.5 for most workloads'). Cache hits 0.05x input; 5m write $5, 1h write $8. Full 1M context at standard pricing. | |||||||
| Claude Sonnet 5.5 Anthropic | claude-sonnet-5-5 |
$2.00 | $0.10 | $10.00 | 1,000,000 | 128,000 | platform.claude.com |
| Mid ('best combination of speed and intelligence'). Cache hits 0.05x input; 5m write $2.50, 1h write $4. Full 1M context at standard pricing. | |||||||
| Claude Haiku 5.5 Anthropic | claude-haiku-5-5 |
$0.10 | $0.01 | $0.50 | 1,000,000 | 128,000 | platform.claude.com |
| Small. Prices are for prompts up to 100,000 tokens; prompts over 100,000 tokens: $0.50 in / $0.05 cached / $2.50 out (5m write $0.625, 1h write $1). | |||||||
| Gemini 4 Argon | gemini-4-argon |
$2.00 | $0.10 | $10.00 | 1,048,576 | 65,536 | ai.google.dev |
| Flagship ('Our flagship reasoning model'). Paid tier only (not on free tier). Page announces new prices from Dec 1, 2026: $4.00 in / $0.20 caching / $20.00 out. No >200k tier listed. Context window is a unified input+output limit of 1,048,576; default sync output 65,536, up to 1,048,576 with long decode. Context caching also has a storage charge. Limits from ai.google.dev/gemini-api/docs/models/gemini-4-argon. | |||||||
| Gemini 3.8 Flash | gemini-3.8-flash |
$0.75 | $0.075 | $3.75 | 1,048,576 | 65,536 | ai.google.dev |
| Mid. Free tier available. Page announces new prices from Jan 1, 2027: $1.50 in / $0.15 caching / $7.50 out. Context caching also has a storage charge. Limits from ai.google.dev/gemini-api/docs/models/gemini-3.8-flash. | |||||||
| Gemini 3.5 Flash-Lite | gemini-3.5-flash-lite |
$0.30 | $0.03 | $2.50 | 1,048,576 | 65,536 | ai.google.dev |
| Small. Free tier available. Note: older gemini-2.5-flash-lite ($0.10/$0.40) and gemini-3.1-flash-lite ($0.25/$1.50) are cheaper and still listed. Limits from ai.google.dev/gemini-api/docs/models/gemini-3.5-flash-lite. | |||||||
| DeepSeek-V4-Pro (DeepSeek-V4-Pro-0813) DeepSeek | deepseek-v4-pro |
$1.32 | $0.044 | $3.96 | 1,000,000 | 384,000 | api-docs.deepseek.com |
| Flagship. Prices are PEAK rates (cache-miss input). Off-peak rates are half: $0.66 in / $0.022 cached / $1.98 out. Peak = 01:00-04:00 and 06:00-10:00 UTC Mon-Fri excluding Chinese public holidays. Context stated as '1M', max output 'Up to 384K'. Only two models are listed, so there is no separate mid tier. | |||||||
| DeepSeek-V4.1-Flash (DeepSeek-V4.1-Flash-1017) DeepSeek | deepseek-flash |
$0.30 | $0.006 | $1.20 | 1,000,000 | 384,000 | api-docs.deepseek.com |
| Small/fast. PEAK rates; off-peak half: $0.15 / $0.003 / $0.60. Legacy names deepseek-v4-flash and deepseek-v4-flash-vision-exp are routed here. Context stated as '1M', max output 'Up to 384K'. | |||||||
| Grok 4.7 xAI | grok-4.7 |
$2.00 | $0.50 | $6.00 | 500,000 | – | docs.x.ai |
| Newest Grok listed. Prices for <200k prompt tokens; at >=200k prompt tokens the whole request is billed $4.00 / $1.00 / $12.00. Context stated as '500k'. Max output not stated. The page does not label flagship/mid/small tiers. | |||||||
| Grok 4.3 xAI | grok-4.3 |
$1.25 | $0.20 | $2.50 | 1,000,000 | – | docs.x.ai |
| Cheaper Grok option (grok-4.20-0309 reasoning/non-reasoning have the same prices). >=200k prompt tokens: $2.50 / $0.40 / $5.00. Context stated as '1M'. Max output not stated. Tier label (mid) is our choice, not xAI's. | |||||||
| Mistral Large 4 Mistral | mistral-large-4-0 |
$1.36 | $0.14 | $4.18 | 1,000,000 | – | docs.mistral.ai |
| Flagship (open-weight, v26.10). ID inferred from the docs URL; page displays 'mistral-large-4+1'. Context stated as '1M'. CONFLICT: mistral.ai/pricing states 'Mistral Large costs $0.5 /M tokens in and $1.5 /M tokens out' (version not named). Docs price used here; recheck before publishing. | |||||||
| Mistral Medium 3.5 Mistral | mistral-medium-3-5-26-04 |
$1.50 | – | $7.50 | 256,000 | – | docs.mistral.ai |
| Mid (v26.04). ID inferred from the docs URL; page displays 'mistral-medium-3-5+2'. Verify exact API ID. Context stated as '256k'. Input/output labels taken from docs.mistral.ai/inference/pricing; model page shows the two numbers unlabeled. Cached price not stated. | |||||||
| Mistral Small 4 Mistral | mistral-small-2603 |
$0.15 | – | $0.60 | 256,000 | – | docs.mistral.ai |
| Small (v26.03, Apache 2.0). Page displays ID 'mistral-small-2603' with an unexplained '+1'. Context stated as '256k'. Input/output labels from docs.mistral.ai/inference/pricing. Cached price not stated. | |||||||
How it checks
Paste a document or open a text file, or type its size in tokens. The checker adds the room you want to keep for the answer and compares the total with each model’s context window, as stated by the provider.
- Fits: the document and the answer take less than 75% of the window.
- Tight: 75 to 100%. It fits, with little room for follow-up questions.
- Too long: the tool says how many parts to split the document into.
Questions
Why keep room for the answer?
The answer is written into the same window as the question. A model with a 1,000,000-token window and a 128,000-token maximum answer needs room for both.
Is the count exact?
Pasted text is counted with OpenAI’s o200k tokenizer. Other providers’ tokenizers cut text differently, so treat results near a limit as tight.
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