Cost per coding-agent request

Is Gemini 3.8 Flash or GPT-6 Astra cheaper for coding agents?

For coding agents, GPT-6 Astra costs 8.5x as much as Gemini 3.8 Flash per request ($0.41 vs $0.048 on our measured traffic), because GPT-6 Astra lists at $10 input, $1 cached input and $50 output per million tokens against $1.50, $0.15 and $7.50 for Gemini 3.8 Flash, and GPT-6 Astra charges more for prompts over 272K tokens.

List prices: Gemini API pricing, OpenAI API pricing, checked 2026-10-13. Request costs: Standard Compute gateway data, 79,301 coding-agent requests from 75 users, Sep 13 to Oct 12, 2026. How we compute this

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Cost per coding-agent request, side by side

Cost at list price	Gemini 3.8 Flash	GPT-6 Astra
Prompt under 100K tokens50% of requests, 87% of input cached	$0.023	$0.15
Prompt of 100K to 272K39% of requests, 88% of input cached	$0.058	$0.39
Prompt over 272K tokens11% of requests, 86% of input cached	$0.13	$1.71
Average request	$0.048	$0.41
100 requests	$4.83	$41.25
Median session16 requests; a session ends after 10 idle minutes	$0.65	$4.49
A month of regular usemedian of 20 users active on 5+ days	$73.52	$583

Each logged request priced at the vendor’s list rates for its own token counts, including cache reads and any higher rate for long prompts. Average output: 698 tokens per request.

Benchmarks, speed and latency, side by side

Artificial Analysis	Gemini 3.8 Flash	GPT-6 Astra
Intelligence Index10 evaluations, 0 to 100	41	53
Terminal-Bench 4.0agentic coding in a terminal	19.7%	59.1%
Output speedmedian	145 tokens/s	63 tokens/s
Time to first answer tokenincludes thinking time	24 s	6.0 min

Source: Artificial Analysis (artificialanalysis.ai). Measured variants: Gemini 3.8 Flash (High), speed on Google; GPT-6 Astra (Max), speed on OpenAI. Fetched October 13, 2026. Artificial Analysis runs Terminal-Bench 4.0 in its own setup, so its scores differ from the tbench.ai leaderboard.

What to watch for

The gap widens on long prompts: under 100K tokens GPT-6 Astra costs 6.7x as much per request, over 272K 13x. Gemini 3.8 Flash figures use Google's standard price from January 1, 2027; until then Google charges half. GPT-6 Astra scores clearly higher on the benchmarks above, so it may finish hard tasks in fewer steps.

FAQ

Is Gemini 3.8 Flash cheaper than GPT-6 Astra for coding agents?

Yes, at list prices. 100 average coding-agent requests cost $4.83 on Gemini 3.8 Flash and $41.25 on GPT-6 Astra. A median 16-request session costs $0.65 vs $4.49. Measured on 79,301 real coding-agent requests (Sep 13 to Oct 12, 2026).

How much does a month of GPT-6 Astra vs Gemini 3.8 Flash cost?

For the median regular user in our data (1,478 requests in 30 days), about $583 on GPT-6 Astra and $73.52 on Gemini 3.8 Flash at list price. Heavier users pay proportionally more.

Gemini 3.8 Flash vs GPT-6 Astra: which is better for agents?

GPT-6 Astra scores higher on output quality (9.3/10 vs 7.9/10), while Gemini 3.8 Flash is the cheaper option. Gemini 3.8 Flash is best for high-throughput agents and Gemini CLI users who want speed and big context; GPT-6 Astra is best for the hardest coding and research tasks in OpenAI-based stacks, where cost is secondary. Live community votes on this page show what people actually prefer.

Can I switch between Gemini 3.8 Flash and GPT-6 Astra in the same agent?

Yes. Model-agnostic agents (Cline, Aider, OpenClaw, Hermes Agent, Kilo Code, OpenCode, Continue) let you swap models per task. Many people route hard tasks to the stronger model and routine work to the cheaper one.