GPT-5
GPT-5 is served by 1 provider that kRouter can route to, with a 400K-token context window and pricing from $3.00 per 1M input tokens. Routing through kRouter means any OpenAI-compatible tool can reach it, with failover to another model if the provider is rate limited.
How to route to GPT-5
| Provider | Route as |
|---|---|
| OpenAI | openai/gpt-5 |
What GPT-5 is suited for
A 400K window is large enough to hold a substantial part of a codebase in one turn, so it suits whole-repo refactors and long agent sessions where the history keeps growing. It supports extended reasoning, which helps on debugging and multi-step planning but spends output tokens on thinking before the answer appears — worth knowing when you set max_tokens. Tool and function calling are supported, so it can drive an agent loop. It accepts images, so screenshots and diagrams can go straight into the prompt. Cached input is billed at $1.50 against $3.00 fresh, which is the difference that matters most for agent work — the same context is resent on every turn.
Specs
- Context window
- 400K
- Max output
- 128K
- Input / 1M
- $3.00
- Output / 1M
- $12.00
- Extended reasoning
- Image input
- Tool / function calling
Cheaper alternatives to GPT-5
Comparable capabilities at a lower rate. With a kRouter combo you can send routine turns to one of these and reserve GPT-5 for the work that actually needs it.
- Gemini 2.5 Pro$2.00 in · $12.00 out per 1M
- Gemini 3 Pro Preview$2.00 in · $12.00 out per 1M
- Gemini 3.1 Pro (Low)$2.00 in · $12.00 out per 1M
- Kimi K2.5$1.20 in · $4.80 out per 1M
GPT-5 FAQ
How much does GPT-5 cost?
GPT-5 is $3.00 per 1M input tokens and $12.00 per 1M output tokens. Cached input is $1.50, which matters a lot for agent work that resends the same context each turn.
Which providers serve GPT-5?
OpenAI serves it. kRouter routes to it as openai/gpt-5.
What is GPT-5's context window?
400K tokens, with up to 128K tokens of output. kRouter publishes this on /v1/models as context_length, so clients read the real number instead of guessing from the model name.
Is there a cheaper alternative to GPT-5?
Yes — Gemini 2.5 Pro ($2.00/1M in), Gemini 3 Pro Preview ($2.00/1M in), Gemini 3.1 Pro (Low) ($2.00/1M in), Kimi K2.5 ($1.20/1M in) are cheaper with comparable capabilities. A kRouter combo can send routine turns to one of those and keep GPT-5 for the work that needs it.
Route to GPT-5 from any tool
kRouter runs locally and gives Claude Code, Cursor, Codex and the rest one endpoint that reaches every provider above — with automatic failover. Free and MIT-licensed.
Install kRouter