Cost per coding-agent request

Is GPT-5.3-Codex or GPT-5.5 cheaper for coding agents?

For coding agents, GPT-5.5 costs 3.3x as much as GPT-5.3-Codex per request ($0.18 vs $0.055 on our measured traffic), because GPT-5.5 lists at $5 input, $0.50 cached input and $30 output per million tokens against $1.75, $0.175 and $14 for GPT-5.3-Codex, and GPT-5.5 charges more for prompts over 272K tokens.

List prices: 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	GPT-5.3-Codex	GPT-5.5
Prompt under 100K tokens50% of requests, 87% of input cached	$0.030	$0.081
Prompt of 100K to 272K39% of requests, 88% of input cached	$0.073	$0.20
Prompt over 272K tokens11% of requests, 86% of input cached	$0.13	$0.74
Average request	$0.055	$0.18
100 requests	$5.55	$18.06
Median session16 requests; a session ends after 10 idle minutes	$0.74	$2.04
A month of regular usemedian of 20 users active on 5+ days	$84.36	$291

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. Both models are priced on the requests up to 400K tokens that fit in both context windows; band shares above describe all requests.

Benchmarks, speed and latency, side by side

Artificial Analysis	GPT-5.3-Codex	GPT-5.5
Intelligence Index10 evaluations, 0 to 100	33 (estimate)	38
Terminal-Bench 4.0agentic coding in a terminal	n/a	14.6%
Output speedmedian	113 tokens/s	105 tokens/s
Time to first answer tokenincludes thinking time	72 s	71 s

Source: Artificial Analysis (artificialanalysis.ai). Measured variants: GPT-5.3 Codex (Xhigh), speed on OpenAI; GPT-5.5 (Xhigh), 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

GPT-5.3-Codex's 400K window cannot take 3% of coding-agent requests, so the comparison uses only requests both can take. The gap widens on long prompts: under 100K tokens GPT-5.5 costs 2.7x as much per request, over 272K 5.6x. GPT-5.5 is superseded: GPT-6.1 Sol costs $0.067 per request.

FAQ

Is GPT-5.3-Codex cheaper than GPT-5.5 for coding agents?

Yes, at list prices. 100 average coding-agent requests cost $5.55 on GPT-5.3-Codex and $18.06 on GPT-5.5. A median 16-request session costs $0.74 vs $2.04. Measured on 79,301 real coding-agent requests (Sep 13 to Oct 12, 2026), counting only the requests up to 400K tokens that both can take.

How much does a month of GPT-5.5 vs GPT-5.3-Codex cost?

For the median regular user in our data (1,478 requests in 30 days), about $291 on GPT-5.5 and $84.36 on GPT-5.3-Codex at list price. Heavier users pay proportionally more.

GPT-5.3-Codex vs GPT-5.5: which is better for agents?

GPT-5.5 scores higher on output quality (7.6/10 vs 6.8/10), while GPT-5.3-Codex is the cheaper option. GPT-5.3-Codex is best for existing Codex setups on an API key that still pin GPT-5.3-Codex; GPT-5.5 is best for existing GPT-5.5 setups on an API key until they move to GPT-6.1 Sol. Live community votes on this page show what people actually prefer.

Can I switch between GPT-5.3-Codex and GPT-5.5 in the same agent?

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

Community vote

Pick a winner in each dimension. You can change your vote any time.

Output Quality

Correctness and depth of what it produces

Agentic Ability

Tool calls, instruction-following, and multi-step tasks

Speed

Tokens per second and time-to-first-token

Value for Money

How much capability you get per dollar

Reliability

Consistent results: fewer refusals, loops and format breaks

Current Claude, GPT, Gemini and open models run on Standard Compute

Standard Compute

Current frontier models Claude Fable 5.1 · GPT-6 Astra

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