Model comparison

Gemini 3.1 Pro vs Gemini 3.6 Flash

Two Google tiers compared on the figures that decide which one a workload actually needs.

Recorded profile verification October 1, 2026Individual provider fields may changeEvidence confidence: Medium — see receipts below

Google

Gemini 3.1 Pro

Frontier

Google

Gemini 3.6 Flash

Balanced

AI model capability comparison
Specification	Gemini 3.1 Pro	Gemini 3.6 Flash
Provider
Provider	Google	Google
Tier
Tier	Frontier	Balanced
Context window
Context window	1.05M	1.05M
Max output
Max output	66K	66K
Input / 1M tokens
Input / 1M tokens	$2	Winner: $0.75
Output / 1M tokens
Output / 1M tokens	$12	Winner: $3.75
Weights
Weights	Closed	Closed
Parameters
Parameters	Not verifiedUnverified	Not verifiedUnverified
Reasoning levels
Reasoning levels	low, medium, high	minimal, low, medium, high
Modalities
Modalities	text, image, video, audio, pdf	text, image, video, audio, pdf
API model id
API model id	gemini-3.1-pro-preview	gemini-3.6-flash
Released
Released	February 19, 2026	July 21, 2026
SWE-bench Verified · source date Gemini 3.1 Pro: 2026-02
SWE-bench Verified · source date Gemini 3.1 Pro: 2026-02	80.6	Not verifiedUnverified
GPQA Diamond · source date Gemini 3.1 Pro: 2026-02
GPQA Diamond · source date Gemini 3.1 Pro: 2026-02	94.3	Not verifiedUnverified
Humanity's Last Exam · source date Gemini 3.1 Pro: 2026-02
Humanity's Last Exam · source date Gemini 3.1 Pro: 2026-02	44.4	Not verifiedUnverified
Terminal-Bench 2.1 · source date Gemini 3.1 Pro: 2026-07, Gemini 3.6 Flash: 2026-07 (comparability not verified)
Terminal-Bench 2.1 · source date Gemini 3.1 Pro: 2026-07, Gemini 3.6 Flash: 2026-07 (comparability not verified)	73.8	78
DeepSWE 1.1 · source date Gemini 3.6 Flash: 2026-08
DeepSWE 1.1 · source date Gemini 3.6 Flash: 2026-08	Not verifiedUnverified	48.6
HLE-Verified · source date Gemini 3.6 Flash: 2026-08
HLE-Verified · source date Gemini 3.6 Flash: 2026-08	Not verifiedUnverified	51.2

Dates beside benchmark scores refer to the linked source’s publication or capture date unless that source explicitly states when it measured the result. A shared URL alone does not establish comparable runs; unverified setups are marked. Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.

Benchmark receipts

Where each score comes from, and how far it can be compared across models.

Source date2026-08
Google DeepMind model evaluation report (vendor; full 1,811-item HLE-Verified set) (Full 1,811-item verified/revised set; differs from original HLE and AA text-only HLE)
Expert reasoning on the verified and revised Humanity's Last Exam question set.
UnknownA distinct question set from original HLE and Artificial Analysis's text-only HLE. Shared dataset and publisher alone do not establish matching model effort, tools, filtering and run configuration; no quality winner is inferred without that evidence.
Source date2026-08
Google DeepMind August 3.7 evaluation report (quoting Datacurve for 3.6 Flash, 48.6%) (High thinking; quoted Datacurve result; July 3.6 report rounds to 49%)
Agentic software engineering: pass@1 on real repo tasks with reported cost per completed task.
Directly comparable
Source date2026-07
Google DeepMind model evaluation report (vendor, Terminus-2 harness)
Agentic terminal work: multi-step tasks executed in a sandboxed shell environment.
Comparable with caveatNot comparable with Terminal-Bench 3.0 or 4.0 (different task sets) or v1; harness configuration (container, time limits) also shifts results.
Source date2026-07
Google DeepMind model evaluation report (vendor, Terminus-2; own Feb report separately reported TB 2.0 = 68.5 — versions preserved)
Agentic terminal work: multi-step tasks executed in a sandboxed shell environment.
Comparable with caveatNot comparable with Terminal-Bench 3.0 or 4.0 (different task sets) or v1; harness configuration (container, time limits) also shifts results.
Source date2026-02
Google DeepMind model evaluation report (vendor, no tools; 51.4 with search+code)
Frontier-knowledge ceiling: extremely hard multi-domain questions written to be near-impossible without deep expertise.
Comparable with caveatSubset/tool configurations (text-only vs with-tools) differ between vendors and materially change scores; must match configuration to compare.
Source date2026-02
Google DeepMind model evaluation report (vendor, no tools, pass@1)
Graduate-level science reasoning: multiple-choice questions written by domain PhDs.
Comparable with caveatDo not treat a fixed two-point band as universal measurement uncertainty; it depends on run count and evaluation setup. Chain-of-thought, prompt, and tool policy must match. The small pool limits fine-grained conclusions, and frontier scores can be near ceiling; Artificial Analysis dropped it from its Intelligence Index in v4.3.
Source date2026-02
Google DeepMind model evaluation report (vendor, Thinking High, avg of 10 runs, +0.6 disclosed adjustment)
Real GitHub issue resolution: does the model's patch pass the hidden tests.
Comparable with caveatPost-audit vendor claims and pre-audit scores sit on different task trust levels; scaffolding (agent harness, compute budget) also dominates results. Never aggregate across scaffolds.

Pricing tiers

Gemini 3.1 Pro: The current Gemini developer guide lists $2/$12 per MTok below 200K input and $4/$18 above 200K, including thinking output. It leaves the exact 200K boundary unspecified; confirm that boundary and other processing/cache tiers before budgeting. The exact API ID remains gemini-3.1-pro-preview. Restricted Gemini 4 Argon is a separate preview and does not make this endpoint stable.

Gemini 3.6 Flash: Intro Standard $0.75/$3.75 per MTok through December 31, 2026; $1.50/$7.50 from January 1, 2027. Output includes thinking tokens. Cached input $0.075, rising to $0.15; storage $0.50/MTok-hour, rising to $1. Batch/Flex input/output are $0.375/$1.875, rising to $0.75/$3.75. Priority $1.35/$6.75, rising to $2.70/$13.50. Grounding tools have separate charges and quotas; free-tier limits differ from paid.

FrontierRecord checked October 1, 2026

Gemini 3.1 Pro

Gemini 3.1 Pro Preview is Google's multimodal Pro endpoint with a 1,048,576-token input limit and 65,536-token output limit.

Best for

Very long documents
Multimodal reasoning
Frontier knowledge work

Watch out

This API endpoint remains Preview. A separate customtools endpoint is optimized for bash/custom-tool workflows and can behave differently on other tasks. Keep endpoint, thinking level and benchmark version matched; restricted Gemini 4 Argon access is a separate lifecycle.

BalancedRecord checked October 1, 2026

Gemini 3.6 Flash

Gemini 3.6 Flash is Google's balanced multimodal Flash tier with a 1M-token context.

Best for

Multimodal pipelines
High-volume processing
Video and audio input

Watch out

An earlier Flash model, still listed as stable. Google reports improvements on selected tasks for later releases; that does not establish a quality increase for every workload. Thinking includes minimal through high; computer use is Preview. Intro pricing doubles January 1, 2027.

When the cheaper one wins

Gemini 3.6 Flash is cheaper on output at $3.75 per million tokens against $12 for Gemini 3.1 Pro — about 3.2×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. On DeepSWE 1.1, Gemini 3.6 Flash is 46.7% Pass@1 at $4.42/task versus Gemini 3.1 Pro at 11.7% / $2.14/task. This compares standard short-context token rates, not total cost per accepted task. Include input, cache, context tiers, schedules, retries and review in your pilot.

Run the model picker

Evidence confidence: Medium

How strong and complete the evidence behind this comparison is — not a prediction of which model is better.

Pricing verified on both sides — Input and output rates are verified for both models.
4/5 core specs verified on both sides — Not published for at least one side: parameter count.
No directly aligned benchmark setup — No benchmark has matching cited sources, source dates, units, effort and recorded run details on both models.
Verified within the last 90 days — Older of the two catalog checks was 25 days ago.
Both models carry source citations — Each side has at least two catalog sources on record.

Source receipts

Each catalog figure was checked against the provider or an independent second source on the date shown.

Gemini 3.1 Pro: Google primary profile — whole-record source check October 1 (accessed 2026-10-01)
Gemini 3.1 Pro: Gemini current API pricing and cache-storage tiers (accessed 2026-10-01)
Gemini 3.1 Pro: Gemini developer guide — exact Preview rates and boundary limitation (accessed 2026-10-01)
Gemini 3.1 Pro: Gemini API 3.1 Pro Preview — exact endpoint and customtools scope (accessed 2026-10-01)
Gemini 3.1 Pro: Google Cloud — Gemini 3.1 Pro (accessed 2026-08-29)
Gemini 3.1 Pro: TechCrunch — Gemini 3.1 Pro (accessed 2026-08-29)
Gemini 3.6 Flash: Google primary profile — whole-record source check October 1 (accessed 2026-10-01)
Gemini 3.6 Flash: Gemini current API pricing and cache-storage tiers (accessed 2026-10-01)
Gemini 3.6 Flash: Gemini thinking — model-specific Interactions levels (accessed 2026-10-01)
Gemini 3.6 Flash: Google — Gemini 3.6 Flash (accessed 2026-08-29)
Gemini 3.6 Flash: Google Cloud Gemini pricing (accessed 2026-08-29)

Related comparisons

Diving deeper on one model? Gemini 3.1 Pro · Gemini 3.6 Flash

Common questions

Gemini 3.1 Pro vs Gemini 3.6 Flash

Answered from the verified figures on this page rather than general guidance.

Is Gemini 3.1 Pro or Gemini 3.6 Flash cheaper for input?

Gemini 3.6 Flash is cheaper at $0.75 per million input tokens, against $2 for Gemini 3.1 Pro — roughly 2.7× the price. Estimate both input and output token volume for your workload. These are base rates; Gemini 3.1 Pro: The current Gemini developer guide lists $2/$12 per MTok below 200K input and $4/$18 above 200K, including thinking output. It leaves the exact 200K boundary unspecified; confirm that boundary and other processing/cache tiers before budgeting. The exact API ID remains gemini-3.1-pro-preview. Restricted Gemini 4 Argon is a separate preview and does not make this endpoint stable. Gemini 3.6 Flash: Intro Standard $0.75/$3.75 per MTok through December 31, 2026; $1.50/$7.50 from January 1, 2027. Output includes thinking tokens. Cached input $0.075, rising to $0.15; storage $0.50/MTok-hour, rising to $1. Batch/Flex input/output are $0.375/$1.875, rising to $0.75/$3.75. Priority $1.35/$6.75, rising to $2.70/$13.50. Grounding tools have separate charges and quotas; free-tier limits differ from paid.

Is Gemini 3.1 Pro or Gemini 3.6 Flash cheaper for output?

Gemini 3.6 Flash is cheaper at $3.75 per million output tokens, against $12 for Gemini 3.1 Pro — roughly 3.2× the price. Estimate both input and output token volume for your workload. These are base rates; Gemini 3.1 Pro: The current Gemini developer guide lists $2/$12 per MTok below 200K input and $4/$18 above 200K, including thinking output. It leaves the exact 200K boundary unspecified; confirm that boundary and other processing/cache tiers before budgeting. The exact API ID remains gemini-3.1-pro-preview. Restricted Gemini 4 Argon is a separate preview and does not make this endpoint stable. Gemini 3.6 Flash: Intro Standard $0.75/$3.75 per MTok through December 31, 2026; $1.50/$7.50 from January 1, 2027. Output includes thinking tokens. Cached input $0.075, rising to $0.15; storage $0.50/MTok-hour, rising to $1. Batch/Flex input/output are $0.375/$1.875, rising to $0.75/$3.75. Priority $1.35/$6.75, rising to $2.70/$13.50. Grounding tools have separate charges and quotas; free-tier limits differ from paid.

Which has the larger context window, Gemini 3.1 Pro or Gemini 3.6 Flash?

Both accept about 1.05M tokens of context, so document length will not decide between them.

Do Gemini 3.1 Pro and Gemini 3.6 Flash support the same reasoning levels?

Gemini 3.1 Pro exposes low, medium, high, while Gemini 3.6 Flash exposes minimal, low, medium, high.

Should I use Gemini 3.1 Pro or Gemini 3.6 Flash?

We classify Gemini 3.1 Pro in the frontier tier and Gemini 3.6 Flash in the balanced tier. Test whether either meets your accuracy, tool-use and latency requirements before choosing on price.

Next step

Choosing between them

The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.

Input price: Gemini 3.6 Flash costs $0.75 per 1M tokens versus $2 for Gemini 3.1 Pro — a 2.7x difference at the headline tier.
Positioning: Gemini 3.1 Pro sits in the frontier tier, Gemini 3.6 Flash in the balanced tier. Compare accuracy, reliability, latency, and cost on representative tasks before choosing.

Run the model picker Estimate stack cost All model comparisons

Choosing a harness rather than a model — Cursor, Copilot, Claude Code, Windsurf, or Lovable? Compare agentic harnesses · Latest releases.