Gemini 4 Hydrogen vs Gemini 3.1 Pro
Hydrogen is cheaper than Gemini 3.1 Pro Preview and has a free API tier that 3.1 Pro lacks: $1.50 / $7.50 per 1M input/output tokens flat, versus $2 / $12 for 3.1 Pro prompts up to 200K tokens and $4 / $18 above. Google’s Hydrogen materials do not benchmark it against 3.1 Pro, and Artificial Analysis currently shows no Intelligence Index v5 score for 3.1 Pro Preview, so there is no like-for-like published score.
Prices: Gemini Developer API pricing page, retrieved 13 November 2026. Source: Google AI Studio / Gemini API docs, Retrieved 13 November 2026 · Source: Google AI Studio / Gemini API docs, Retrieved 13 November 2026 · Source: Google DeepMind, 12 November 2026
| Gemini 4 Hydrogen | Gemini 3.1 Pro Preview | |
|---|---|---|
| Model ID | gemini-4-hydrogen | gemini-3.1-pro-preview |
| Input / 1M | $1.50 (flat across 1M) | $2 (≤200K prompt) · $4 (>200K) |
| Output / 1M (incl. thinking) | $7.50 | $12 (≤200K) · $18 (>200K) |
| Context caching | $0.075, implicit only | $0.20 / $0.40 + $4.50 per 1M tokens per hour storage |
| Free tier | Yes | Not available |
| Released | 12 Nov 2026 | 19 Feb 2026 (per Artificial Analysis) |
| Thinking levels | low, medium, high (default), xhigh | — |
Cost example (our arithmetic)
10M input + 2M output tokens with prompts under 200K: Hydrogen $30; 3.1 Pro Preview 10 × $2 + 2 × $12 = $44. With prompts over 200K: 3.1 Pro 10 × $4 + 2 × $18 = $76; Hydrogen still $30.
What we can say about quality
- Hydrogen’s knowledge cutoff is March 2026 (model card); 3.1 Pro Preview was released in February 2026.
- Google says Hydrogen scores 51 on the Artificial Analysis Intelligence Index at high and 54 at xhigh, above Gemini 4 Argon’s 50. No v5 index score is shown for 3.1 Pro Preview.
- 3.1 Pro is still labelled Preview; Hydrogen is a short-term GA release with at least 45 days’ retirement notice (Google Cloud guide).
Source: Google Blog, 12 November 2026 · Source: Google Cloud documentation, Last updated 12 November 2026
More comparisons vs Claude Sonnet 5.5 vs Claude Opus 5.5 vs GPT-6.1 Sol vs 3.8 Flash vs Argon / Carbon All benchmarks Pricing
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Speed, tokens per second and cost per task
At its default high level, Hydrogen measured 171 output tokens/s and 8.3 minutes per Artificial Analysis Index task; the fastest level of the other model here measured 113 tok/s, so Hydrogen streamed about 1.5× as fast in AA’s runs.
| Model · thinking/effort level | AA Intelligence Index | Output speed (tok/s) | Minutes per AA Index task | Time to first answer token (s) |
|---|---|---|---|---|
| Gemini 4 Hydrogen · xhigh | 54 | 178 | 14.5 | 44.79 |
| Gemini 4 Hydrogen · high | 51 | 171 | 8.3 | 17.37 |
| Gemini 4 Hydrogen · medium | 41 | 174 | 3.8 | 11.81 |
| Gemini 4 Hydrogen · low | 27 | 173 | 1.4 | 5.58 |
| Gemini 3.1 Pro Preview · default | — | 113 | — | 15.49 |
| Model | Official list price (input / output per 1M) | Our arithmetic per task (50K in + 8K out) | ×1,000 tasks | AA measured cost per Index task |
|---|---|---|---|---|
| Gemini 4 Hydrogen | $1.50 / $7.50 flat | $0.135 | $135 | $3.16 (xhigh) |
| Gemini 3.1 Pro Preview | $2 / $12 (≤200K prompt); $4 / $18 above | $0.196 (≤200K prompt) | $196 | not published |
Output tokens Artificial Analysis recorded while running its whole Intelligence Index (more tokens = more cost and time for the same work): Gemini 4 Hydrogen: xhigh 304M, high 110M, medium 54.4M, low 20.3M.
Source: Artificial Analysis: Gemini 4 Hydrogen · Artificial Analysis: Gemini 3.1 Pro Preview (retrieved 14 November 2026) · Source: Google AI Studio / Gemini API docs, Retrieved 13 November 2026
Plug in your own token counts: Hydrogen cost calculator · all comparisons.