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Gemini 3.5 Flash vs GPT-5.6 Terra

Compare Gemini 3.5 Flash and GPT-5.6 Terra side-by-side. See how these vision models stack up in Open Prompt, Image Captioning, OCR, Classification, and Object Detection.

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GoogleGemini 3.5 Flash
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OpenAIGPT-5.6 Terra
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Models in this comparison

Gemini 3.5 Flash vs GPT-5.6 Terra on Vision Evals

Gemini 3.5 Flash scores higher on 5 of the six Vision Evals tasks.

The widest gap is Reasoning, where Gemini 3.5 Flash leads 82.1% to 60.9%.

Overall, Gemini 3.5 Flash averages 86.0% (#2 of 60) against 73.8% (#24 of 60) for GPT-5.6 Terra.

GPT-5.6 Terra is both cheaper ($0.0088 vs $0.011 per sample) and faster (7.7s vs 14.8s per sample).

Gemini 3.5 FlashGPT-5.6 Terra

Gemini 3.5 Flash vs GPT-5.6 Terra Comparison Table

Evals updated October 7, 2026Pricing updated October 7, 2026

PropertyGemini 3.5 FlashGPT-5.6 Terra
OrganizationGoogleOpenAI
Categoryclosedclosed
Modalitymultimodalmultimodal
Release DateMay 2026Jul 2026
Context Window1.0M1.1M
ParametersUnknownUnknown
LicenseProprietaryProprietary
Pricing per 1M tokens
Input $/1M$1.50$2.00
Output $/1M$9.00$12.00
Vision Tasks
CaptioningDemoDemo
Chart Question AnsweringSupportedSupported
ClassificationDemoDemo
Document Question AnsweringSupportedSupported
Image TaggingSupportedSupported
Multi-Label ClassificationSupportedSupported
Object DetectionDemoDemo
OCRDemoDemo
Vision LanguageSupportedSupported
Visual Question AnsweringDemoDemo
Model Features
Foundation VisionSupportedSupported
LLMs with Vision CapabilitiesSupportedSupported
Multimodal VisionSupportedSupported
Vision Evalsground-truth scores across 6 vision tasks, pooled at low effort
Overall
86.0%
73.8%
Avg cost / sample$0.011$0.0088
Avg speed / sample14.77s7.74s
By task
Object Detection (low)
70.6%
±2.0, Mean of 3 runs, range 68.7 to 72.6
$0.016
60.6%
±0.2, Mean of 3 runs, range 60.3 to 60.7
$0.014
Object Detection (high)
69.8%
±1.8, Mean of 3 runs, range 67.5 to 71.1
$0.021
61.3%
±0.4, Mean of 3 runs, range 60.8 to 61.6
$0.026
Counting (low)
80.6%
±0.7, Mean of 3 runs, range 79.7 to 81.1
$0.0075
65.8%
±2.0, Mean of 3 runs, range 63.5 to 67.6
$0.0056
Counting (high)
82.4%
±0.0, Mean of 3 runs, range 82.4 to 82.4
$0.017
62.6%
±2.7, Mean of 3 runs, range 59.5 to 64.9
$0.0076
Identification (low)
99.0%
±1.6, Mean of 3 runs, range 96.9 to 100.0
$0.0040
86.5%
±1.6, Mean of 3 runs, range 84.4 to 87.5
$0.0034
Identification (high)
97.9%
±1.6, Mean of 3 runs, range 96.9 to 100.0
$0.0068
86.5%
±3.1, Mean of 3 runs, range 84.4 to 90.6
$0.0038
OCR (low)
89.3%
±1.6, Mean of 3 runs, range 88.0 to 91.1
$0.016
89.4%
±0.8, Mean of 3 runs, range 88.8 to 90.3
$0.012
OCR (high)
88.9%
±0.2, Mean of 3 runs, range 88.7 to 89.1
$0.035
89.4%
±0.6, Mean of 3 runs, range 88.8 to 90.1
$0.023
Data Extraction (low)
94.5%
±0.5, Mean of 3 runs, range 93.8 to 94.8
$0.0037
79.7%
±0.5, Mean of 3 runs, range 79.4 to 80.4
$0.0038
Data Extraction (high)
95.5%
±1.5, Mean of 3 runs, range 93.8 to 96.9
$0.0066
80.4%
±1.0, Mean of 3 runs, range 79.4 to 81.4
$0.0043
Reasoning (low)
82.1%
±2.0, Mean of 3 runs, range 80.1 to 84.1
$0.0082
60.9%
±2.0, Mean of 3 runs, range 59.6 to 63.6
$0.0051
Reasoning (high)
81.0%
±1.7, Mean of 3 runs, range 79.5 to 82.8
$0.018
65.3%
±1.0, Mean of 3 runs, range 64.2 to 66.2
$0.0067

Gemini 3.5 Flash vs GPT-5.6 Terra: Overview

Gemini 3.5 Flash

Gemini 3.5 Flash is a multimodal language model developed by Google DeepMind and released at Google I/O 2026. It is built on the Gemini 3 Flash reasoning foundation and introduces configurable thinking levels (minimal, low, medium, and high) that allow developers to tune the depth of internal reasoning before a response is generated. The model accepts text, image, video, audio, and PDF inputs and produces text output, with a 1 million token context window and up to 65,000 output tokens per request. It is natively multimodal, processing visual inputs alongside text to support tasks such as image captioning, classification, optical character recognition, object detection, and visual grounding, where the model references specific regions within an image or video frame.

Its vision capabilities extend to interpreting UI screenshots, diagrams, charts, and real-world scenes, as well as understanding video and live frame sequences for activity and scene recognition. The model supports combined tool use, including Google Search, URL context, code execution, and custom functions, within a single request, and it uses reasoning context from previous turns when thought signatures are present in the conversation history, enabling persistent multi-turn reasoning chains. Gemini 3.5 Flash carries a knowledge cutoff of January 2026 and is available via the Gemini API, Google AI Studio, Google Antigravity, and the Gemini Enterprise Agent Platform.

GPT-5.6 Terra

GPT-5.6 Terra is the mid-tier reasoning model in OpenAI's GPT-5.6 family, which also includes the flagship Sol and the lightweight Luna. Introduced in a limited preview on June 26, 2026, and made broadly available on July 9, 2026, Terra accepts text and image input and produces text output, supporting vision, function calling, tool use, and agentic workflows. It is designed as a balanced option for everyday professional and production workloads — including coding assistance, document analysis, customer support, and multi-step agent tasks — where both output quality and cost efficiency matter. OpenAI positions Terra as delivering performance competitive with GPT-5.5 at approximately half the price, with a context window of around 1,050,000 tokens. On Terminal-Bench 2.1, Terra scores 84.3%, matching Claude Fable 5 on that benchmark. Under OpenAI's Preparedness Framework, Terra is rated High for cybersecurity and biological capabilities, meaning it demonstrates meaningful capability in those domains without reaching the Critical threshold.

GPT-5.6 introduces a new naming convention in which the generation number (5.6) is paired with a durable capability tier name (Sol, Terra, or Luna), allowing each tier to advance on its own schedule. Terra carries the API identifier gpt-5.6-terra and supports the same reasoning effort controls available across the family, including adjustable reasoning depth. The model includes prompt caching with explicit cache breakpoints and a 30-minute minimum cache life, with cache writes billed at 1.25x the uncached input rate and cache reads receiving a 90% discount. GPT-5.6 Terra is a proprietary, closed-weights model served through the OpenAI API, Codex, and ChatGPT.

Frequently Asked Questions

On Roboflow's Vision Evals, Gemini 3.5 Flash performed better. It scores higher on 5 of the six vision tasks and averages 86.0% (#2 of 60) against 73.8% (#24 of 60) for GPT-5.6 Terra. These scores measure vision capabilities only; either model may perform differently on work outside this benchmark's tasks.

Yes. On the Vision Evals Reasoning benchmark at low effort, Gemini 3.5 Flash leads with 82.1% against 60.9%. This is the widest gap between the two models across the benchmark's tasks.

GPT-5.6 Terra is cheaper to run. Across Roboflow's Vision Evals task mix it averaged $0.0088 per sample against $0.011. Gemini 3.5 Flash is priced at $1.50 per 1M input tokens and $9.00 per 1M output; GPT-5.6 Terra is priced at $2.00 per 1M input tokens and $12.00 per 1M output. Actual costs depend on your image sizes, prompts, and output length.

GPT-5.6 Terra is faster. Across Roboflow's Vision Evals it averaged 7.7s per inference against 14.8s. Latency varies with image size, prompt length, and provider load, so treat these as relative rather than guaranteed figures.

Yes. The comparison demo on this page runs both models on the same image side by side for open prompts and image captioning in the free Roboflow Playground. You can try it instantly, and a free account unlocks unlimited runs.