サブスク vs API

自分の使用量で AI サブスクリプションと従量課金 API を比較します。サブスクリプションは token ではなく時間ウィンドウ単位の課金なので、正確な損益分岐点は存在しません。結果は範囲で示し、キャッシュ感度と各プランの確認日を併記します。

プランの料金と枠は手作業で管理しており、提供元ごとの個別確認は行っていません。API 価格はカタログから読み込むため、価格基準を変えると結論が逆転することがあります。枠の規則は頻繁に変わるため、公式ページを優先してください。

1 日あたりのプロンプト数

1 回の呼び出しの入力 token

1 回の呼び出しの出力 token

キャッシュヒット率 70%

1 プロンプトあたりのモデル呼び出し数：8

チャットでは約 1 回。エージェントは計画・検索・ツール呼び出し・要約を行うため、1 プロンプトで 5〜30 回の呼び出しが発生します。token 単価が安いモデルでもタスク単価では高くなるのはこのためです。

API 価格の基準

一次提供元の表示価格で、一次提供元のサブスクと同種の比較対象になります。

シナリオプリセット

この使用量ならおよそ月 4,800 回のモデル呼び出しです。

費用の範囲はキャッシュヒット率の不確実性（±15 ポイント）から、キャパシティの範囲は各ウィンドウ枠の保守的／楽観的な読み方から出ています。サブスクの枠は時間ウィンドウであり固定の token 数に還元できないため、損益分岐点は点ではなく領域です。

1 日未満のローリングウィンドウは、月あたり 176 稼働時間（8 時間 × 22 日）を仮定して換算します。日次・週次・月次の上限はカレンダーウィンドウなので割り引きません。

枠を算出できないプラン

絶対値の枠が公開されていない、またはモデル呼び出し数に換算できない単位で課金されるプランです。数字を当てはめず、そのまま列挙しています。

OpenAI Free無料Model and feature limits are dynamic and no absolute monthly or message cap is published.
OpenAI Go$8.00Higher limits than Free are published without an absolute message or monthly allowance.
OpenAI Plus$20.00Advanced-model and feature limits are dynamic; the pricing page gives no absolute API-call equivalent.
OpenAI Pro $100$100.00The 5× usage statement is relative to Plus and cannot be converted to an absolute API-call allowance.
OpenAI Pro $200$200.00The 20× usage statement has no absolute API-call equivalent; new subscriptions and upgrades are temporarily paused.
OpenAI Business Standard$25.00Business usage is subject to service guardrails and has no absolute published API-call allowance.
OpenAI Business Premium$125.00Premium usage is relative to the Standard seat and has no absolute published API-call allowance.
Anthropic Free無料Usage depends on the model, conversation and feature; no absolute cap is published.
Anthropic Pro$20.00Usage credits and weekly limits depend on task and model; no absolute API-call allowance is published.
Anthropic Max 5x$100.00The 5× statement is relative to Pro and task-dependent, not an absolute API-call allowance.
Anthropic Max 20x$200.00The 20× statement is relative to Pro and task-dependent, not an absolute API-call allowance.
Anthropic Team$25.00Per-seat usage is not published as an absolute API-call allowance.
Google AI Plus$4.99The plan states a relative 2× usage limit; compute-based limits cannot be converted to API calls.
Google AI Pro$19.99The plan states a relative 4× usage limit; compute-based limits cannot be converted to API calls.
Google AI Ultra 5x$99.99Usage is measured as compute and varies with the prompt, features and conversation; no API-call cap is published.
Google AI Ultra 20x$199.99Usage is measured as compute and varies with the prompt, features and conversation; no API-call cap is published.
xAI Free無料Rate limits are not published as absolute model-call numbers.
xAI SuperGrok$30.00Higher rate limits are not published as absolute model-call numbers.
xAI SuperGrok Plus$100.00Higher rate limits are not published as absolute model-call numbers.
Perplexity Free無料Pro-search and feature limits are not equivalent to a fixed model-call allowance.
Perplexity Pro$20.00Search and research usage bundles retrieval, tools and generation, so it cannot map to API model calls.
Perplexity Max$200.00Monthly AI credits vary in cost by research feature and model, so they cannot map to API model calls.
Mistral Free無料Vibe feature limits and Studio credits do not specify a fixed model-call allowance.
Mistral Pro$14.99Vibe feature limits and included Studio API credits do not specify a fixed model-call allowance.
Mistral Team$24.99Per-seat Vibe use and included credits do not specify a fixed model-call allowance.
GitHub Free無料Chat, agent and completion limits are product-specific and are not API model-call limits.
GitHub Pro$10.00Included GitHub AI Credits have feature- and model-dependent costs, not a fixed API-call conversion.
GitHub Pro+$39.00Included GitHub AI Credits have feature- and model-dependent costs, not a fixed API-call conversion.
GitHub Max$100.00The $100 monthly AI Credit allocation has feature- and model-dependent costs, not a fixed API-call conversion.
GitHub Business$19.00Included GitHub AI Credits have feature- and model-dependent costs, not a fixed API-call conversion.
GitHub Enterprise$39.00Included GitHub AI Credits have feature- and model-dependent costs, not a fixed API-call conversion.
Cursor Hobby無料Agent-request limits are not published as absolute model-call numbers.
Cursor Pro$20.00Agent limits and usage-based features do not specify a fixed model-call allowance.
Cursor Pro+$60.00Agent limits and usage-based features do not specify a fixed model-call allowance.
Cursor Ultra$200.00Agent limits and usage-based features do not specify a fixed model-call allowance.
Cursor Teams Standard$40.00Team use and usage-based features do not specify a fixed model-call allowance.