Cheaper overall
Gemini 3.8 Flash
67% lower blended rate
Higher benchmark scores
GPT-5.6 Terra
leads on 6 of 11 figures
Bigger context window
GPT-5.6 Terra
1,050,000 vs 1,048,576 tokens
Cheaper cached input
Gemini 3.8 Flash
$0.075 vs $0.20, 63% less
Where each one wins
Gemini 3.8 Flash
- Cheaper input tokens $0.75 vs $2.00, 63% less
- Cheaper output tokens $3.75 vs $12.00, 69% less
- Cheaper cached input $0.075 vs $0.20, 63% less
- Cheaper on all four workloads
- Higher graduate-level science (GPQA Diamond) 95.3 vs 92.5
- Higher expert-exam performance (Humanity's Last Exam) 47.8 vs 42.9
- Higher scientific coding (SciCode) 56.6 vs 55
- Ahead on 2 more benchmark figures
GPT-5.6 Terra
- Larger context window 1,050,000 tokens
- Longer maximum output 128,000 tokens
- Higher overall intelligence (Intelligence Index) 42.1 vs 40.9
- Higher coding ability (Coding Index) 76.7 vs 76.3
- Higher multi-step tool use (Agentic Index) 43.2 vs 40.2
- Ahead on 3 more benchmark figures
- Offers Batch, Flex and Priority pricing not listed for Gemini 3.8 Flash
What four workloads cost
One run, and the same run a thousand times.
Gemini 3.8 Flash is cheaper on all four workloads, by much the same margin each time — about 3.5 times, from $0.0026 against $0.0080 on a chat turn to $0.3113 against $1.65 on a long document.
| Workload | Gemini 3.8 Flash | GPT-5.6 Terra | ×1,000 | Difference |
|---|---|---|---|---|
| Chat turn 1,000 in / 500 out | $0.0026 | $0.0080 | $2.63 / $8.00 | Gemini 3.8 Flash is 67% cheaper |
| RAG answer 10,000 in / 800 out | $0.0105 | $0.0296 | $10.50 / $29.60 | Gemini 3.8 Flash is 65% cheaper |
| Agent loop 32,000 in / 700 out × 20 calls | $0.1275 | $0.3680 | $127.50 / $368.00 | Gemini 3.8 Flash is 65% cheaper |
| Long document 400,000 in / 3,000 out | $0.3113 | $1.65 | $311.25 / $1,654.00 | Gemini 3.8 Flash is 81% cheaper |
Price per 1M tokens
Above 272,000 input tokens the rates change, and the new rate applies to the whole request, not just the tokens past that point: GPT-5.6 Terra's input goes from $2.00 to $4.00. It does not change which of the two is cheaper.
| Context band | Price | Gemini 3.8 Flash | GPT-5.6 Terra | Difference |
|---|---|---|---|---|
| Prompts up to 272,000 tokens | Input | $0.75 | $2.00 | Gemini 3.8 Flash is 63% cheaper |
| Prompts up to 272,000 tokens | Cached input | $0.075 | $0.20 | Gemini 3.8 Flash is 63% cheaper |
| Prompts up to 272,000 tokens | Output | $3.75 | $12.00 | Gemini 3.8 Flash is 69% cheaper |
| Prompts over 272,000 tokens | Input | $0.75 | $4.00 | Gemini 3.8 Flash is 81% cheaper |
| Prompts over 272,000 tokens | Cached input | $0.075 | $0.40 | Gemini 3.8 Flash is 81% cheaper |
| Prompts over 272,000 tokens | Output | $3.75 | $18.00 | Gemini 3.8 Flash is 79% cheaper |
Blended: Gemini 3.8 Flash $1.50, GPT-5.6 Terra $4.50 per 1M — one rate at 3:1 input to output, for comparing two models at a glance.
Gemini 3.8 Flash priced by Perplexity, GPT-5.6 Terra by OpenAI. Standard tier, pay-as-you-go.
Other pricing tiers
Only GPT-5.6 Terra lists Batch, Flex and Priority, at up to 50% off its own standard rate; Gemini 3.8 Flash offers none of them.
Every tier either model sells is here, so this is the whole price sheet. A saving is measured against that model's own standard rate — how we read tiers.
| Tier | Gemini 3.8 Flash | GPT-5.6 Terra | Cheaper |
|---|---|---|---|
| Batch only on GPT-5.6 Terra | Not offered | $1.00 in / $6.00 out 50% off Standard | — |
| Flex only on GPT-5.6 Terra | Not offered | $1.00 in / $6.00 out 50% off Standard | — |
| Priority only on GPT-5.6 Terra | Not offered | $4.00 in / $24.00 out | — |
Benchmarks
They share 11 figures: Gemini 3.8 Flash leads on 5, GPT-5.6 Terra on 6. The widest gap is 32.7 points, on answer reliability (Omniscience Non-Hallucination).
Overall intelligence
Intelligence Index — Overall intelligence across reasoning, knowledge & math evals
GPT-5.6 Terra ahead by 1.2
Coding ability
Coding Index — Coding ability across software-engineering evals
GPT-5.6 Terra ahead by 0.4
Multi-step tool use
Agentic Index — Tool use & multi-step agent task performance
GPT-5.6 Terra ahead by 3
Graduate-level science
GPQA Diamond — Graduate-level questions in biology, chemistry & physics
Gemini 3.8 Flash ahead by 2.8
Expert-exam performance
Humanity's Last Exam — Expert-level questions across many academic domains
Gemini 3.8 Flash ahead by 4.9
Long-context reasoning
AA-LCR — Long-context reasoning across large inputs
GPT-5.6 Terra ahead by 1.7
Scientific coding
SciCode — Research-level scientific coding tasks
Gemini 3.8 Flash ahead by 1.6
Physics research reasoning
CritPt — Unpublished physics research reasoning problems
GPT-5.6 Terra ahead by 11.7
Real-world task performance
GDPval — Economically valuable, real-world knowledge work
GPT-5.6 Terra ahead by 1
Factual accuracy
Omniscience Accuracy — Breadth of factual knowledge across domains
Gemini 3.8 Flash ahead by 7.8
Answer reliability
Omniscience Non-Hallucination — How reliably the model avoids fabricated answers
Gemini 3.8 Flash ahead by 32.7
Each figure is that model's best published run, with the effort level named beside it — where these scores come from.
Specifications
GPT-5.6 Terra holds 1,424 more input tokens in one request. Gemini 3.8 Flash also takes audio and video. Only Gemini 3.8 Flash lists computer use.
| Specification | Gemini 3.8 Flash | GPT-5.6 Terra |
|---|---|---|
| Context window | 1,048,576 tokens | 1,050,000 tokens |
| Max output | 65,536 tokens | 128,000 tokens |
| Takes in | Text, audio, image, video, file | Text, image, file |
| Puts out | Text | Text |
| Knowledge cutoff | — | 16 Feb 2026 |
| Released | 2 Sep 2026 | 9 Jul 2026 |
| Status | Active | Active |
| Sold by | Perplexity | OpenAI, Perplexity |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Web search | Not listed | Not listed |
| Prompt caching | Yes | Yes |
| Code execution | Yes | Yes |
| Computer use | Yes | Not listed |
| Open weights | Not listed | Not listed |
| Reasoning | Yes | Yes |
FAQs
- Is Gemini 3.8 Flash cheaper than GPT-5.6 Terra?
- Yes. A 1,000-token prompt with a 500-token reply costs $0.0026 on Gemini 3.8 Flash and $0.0080 on GPT-5.6 Terra, and the same model is cheaper on every workload on this page.
- How much do Gemini 3.8 Flash and GPT-5.6 Terra cost per 1M tokens?
- Gemini 3.8 Flash costs $0.75 for input and $3.75 for output. GPT-5.6 Terra costs $2.00 and $12.00. Standard pay-as-you-go rates, as of 10 Sep 2026.
- Which is better, Gemini 3.8 Flash or GPT-5.6 Terra?
- On published benchmarks, GPT-5.6 Terra. It leads on 6 of the 11 figures both models report, including overall intelligence (Intelligence Index), where it scores 42.1 against 40.9.
- Does Gemini 3.8 Flash or GPT-5.6 Terra offer batch pricing?
- GPT-5.6 Terra only. Its batch input costs $1.00, 50% off its standard rate, and Gemini 3.8 Flash lists no batch tier at all.
- Does Gemini 3.8 Flash or GPT-5.6 Terra have a bigger context window?
- GPT-5.6 Terra, at 1,050,000 tokens against 1,048,576. That is 1,424 more input tokens in a single request.