# Gemini 4 Hydrogen vs Gemini 4 Carbon

> Markdown mirror of https://router.one/models/compare/gemini-4-hydrogen-vs-gemini-4-carbon for AI assistants and crawlers. Router One is a unified, OpenAI-compatible LLM API gateway.

Gemini 4 Hydrogen is the lower-priced of the two on Router One — about 46% less on a 1M-input + 1M-output mix. Both carry a 1.05M context window. Both answer on /v1/chat/completions. Gemini 4 Hydrogen is in no plan and bills the wallet; Gemini 4 Carbon counts against the Premium models allowance on Pro, Max and Ultra.

Gemini 4 Hydrogen and Gemini 4 Carbon compared on current per-token rates, context window, and capabilities — both callable through one OpenAI-compatible endpoint that logs each request it forwards.

## Gemini 4 Hydrogen vs Gemini 4 Carbon: rates, context window, and capabilities

| Spec | Gemini 4 Hydrogen | Gemini 4 Carbon |
| --- | --- | --- |
| Input / 1M tokens | $0.45 | $0.84 |
| Output / 1M tokens | $2.25 | $4.20 |
| Cached input / 1M tokens | $0.0225 | $0.84 |
| Context window | 1.05M | 1.05M |
| Capabilities | Chat, Streaming, Tool calling, Vision | Chat, Streaming, Tool calling, Vision |
| Subscription plans | Not in any plan — wallet | Premium models — Pro, Max, Ultra |
| Detail page | [Gemini 4 Hydrogen](https://router.one/models/gemini-4-hydrogen) | [Gemini 4 Carbon](https://router.one/models/gemini-4-carbon) |

## What does 1M tokens cost on Gemini 4 Hydrogen vs Gemini 4 Carbon?

For a workload of 1M input plus 1M output tokens at current rates: Gemini 4 Hydrogen comes to $2.70, Gemini 4 Carbon comes to $5.04 — Gemini 4 Hydrogen is about 46% cheaper on this mix. Real workloads skew heavily toward input tokens, so weigh the input rate by your own ratio; the cached-input row above is the posted catalog rate for that model.

## Switch between Gemini 4 Hydrogen and Gemini 4 Carbon

The API key, base URL, endpoint and request shape stay the same — Router One serves both on /v1/chat/completions, so switching is a model-string change. Per Google's What's new in Gemini 4 Hydrogen page (checked 2026-11-13), on Google's own Gemini API the two models share the same unified context window, long decode architecture and built-in tools, and adding or switching to Gemini 4 Hydrogen from Gemini 4 Carbon needs no request schema changes; Gemini 4 Hydrogen defaults to the high thinking level and supports xhigh, while Gemini 4 Carbon defaults to medium and caps at high. Per the same Google page (checked 2026-11-13), Google positions Gemini 4 Hydrogen as fast and efficient for everyday coding, interactive web apps, tool-using agents and multimodal document workflows, and Gemini 4 Carbon as its strongest frontier model, which spends more thinking tokens per turn on hard architecture, debugging, science and security audits. On a Pro, Max or Ultra plan the billing differs: as of the 2026-11-13 plan response, Gemini 4 Hydrogen is in no plan tier and bills the wallet per token; Gemini 4 Carbon counts against the Premium models allowance. Run your own prompts on both before you move a workload.

`compare.sh`

```bash
curl https://api.router.one/v1/chat/completions \
  -H "Authorization: Bearer sk-your-router-one-key" \
  -H "Content-Type: application/json" \
  -d '{"model": "google/gemini-4-hydrogen", "messages": [{"role": "user", "content": "Hello"}]}'

# Same request, other model — change one string:
#   "model": "google/gemini-4-carbon"
```

## FAQ

### Is Gemini 4 Hydrogen cheaper than Gemini 4 Carbon?

Input: Gemini 4 Hydrogen $0.45 vs Gemini 4 Carbon $0.84 / 1M tokens; Gemini 4 Hydrogen has the lower rate. Output: Gemini 4 Hydrogen $2.25 vs Gemini 4 Carbon $4.20 / 1M tokens; Gemini 4 Hydrogen has the lower rate. Total cost depends on the workload's input, output and cache usage. Rates change; the /models page is the live source of truth.

### Is Gemini 4 Hydrogen or Gemini 4 Carbon included in a Router One subscription?

Gemini 4 Hydrogen is in no Router One plan, so every call bills the wallet per token. Gemini 4 Carbon counts against the Premium models allowance on Pro, Max and Ultra: Pro 300, Max 1,000 and Ultra 5,000 requests per 30-day cycle, shared by every model in that tier. Requests beyond a plan's allowance bill the wallet per token.

### Can I switch between Gemini 4 Hydrogen and Gemini 4 Carbon without changing code?

The API key, base URL, endpoint and request shape stay the same — Router One serves both on /v1/chat/completions, so switching is a model-string change. Per Google's What's new in Gemini 4 Hydrogen page (checked 2026-11-13), on Google's own Gemini API the two models share the same unified context window, long decode architecture and built-in tools, and adding or switching to Gemini 4 Hydrogen from Gemini 4 Carbon needs no request schema changes; Gemini 4 Hydrogen defaults to the high thinking level and supports xhigh, while Gemini 4 Carbon defaults to medium and caps at high. Per the same Google page (checked 2026-11-13), Google positions Gemini 4 Hydrogen as fast and efficient for everyday coding, interactive web apps, tool-using agents and multimodal document workflows, and Gemini 4 Carbon as its strongest frontier model, which spends more thinking tokens per turn on hard architecture, debugging, science and security audits. On a Pro, Max or Ultra plan the billing differs: as of the 2026-11-13 plan response, Gemini 4 Hydrogen is in no plan tier and bills the wallet per token; Gemini 4 Carbon counts against the Premium models allowance. Run your own prompts on both before you move a workload.

### Where do these numbers come from?

Specs and prices on this page render from the live Router One catalog — the same data as the /models page — and refresh with it. Pricing methodology is documented on /pricing-methodology. Rates on this page were read from the live catalog on 2026-11-13 (UTC) and refresh within the hour.

## More comparisons

- [Gemini 4 Carbon vs Gemini 4 Argon](https://router.one/models/compare/gemini-4-carbon-vs-gemini-4-argon)
- [Gemini 4 Hydrogen vs Gemini 3.8 Flash](https://router.one/models/compare/gemini-4-hydrogen-vs-gemini-3-8-flash)
- [Gemini 3.5 Flash Lite vs Gemini 3.1 Flash Lite](https://router.one/models/compare/gemini-3-5-flash-lite-vs-gemini-3-1-flash-lite)
- [Gemini 3.5 Flash Lite vs Gemini 3.5 Flash](https://router.one/models/compare/gemini-3-5-flash-lite-vs-gemini-3-5-flash)

## See also

- Canonical page: https://router.one/models/compare/gemini-4-hydrogen-vs-gemini-4-carbon
- All model comparisons: https://router.one/models/compare
- All models & prices: https://router.one/models (markdown: https://router.one/models.md)
- Pricing: https://router.one/pricing
- Gemini API in China: https://router.one/gemini-api-china
- Gemini 4 Hydrogen API guide: https://router.one/blog/gemini-4-hydrogen-api-guide
- Gemini 4 Carbon API guide: https://router.one/blog/gemini-4-carbon-api-guide
- Cost calculator: https://router.one/llm-cost-calculator
- Pricing methodology: https://router.one/pricing-methodology