GPT-5.5
openai/gpt-5.5
- Latency
- 421ms
- Cost
- $0.00231
- Per 1,000
- $2.31
97 in · 61 out (54 reasoning) · 1 words · checks 1/1
- exact
90
Judge: The output is exactly '90' with no extraneous commentary, matching the rubric requirement perfectly.
Reasoning · 1 checks · max 800 tokens · benched 2026-09-16
GPT-5.5 vs GPT-5.4 vs GPT-5.4 mini vs GPT-5.4 Nano vs GPT-5.3-Codex on when does the faster train catch up?
OpenAI models side by side on "When does the faster train catch up?": GPT-5.4 Nano scores 10/10; GPT-5.4 Nano is the cheapest answer scoring 8+ at $0.18 per 1,000 runs. Outputs, checks, judge reasons, latency and cost.
The prompt every model received
System
Think carefully, then give only the final answer in the requested format.
User
Train A leaves a station at 09:10 travelling at a constant 80 km/h. Train B leaves the same station on the same track at 09:40 travelling at a constant 120 km/h in the same direction. How many minutes after 09:10 does train B catch up with train A? Reply with only the whole number of minutes.
Rubric for the judge: The single correct answer 90, with no working shown in the final output.
Side by side
Every cell is one OpenRouter call at temperature 0 with the prompt's token cap and reasoning effort "low" where the model supports it. Cost is usage × the catalogue rate in models.json. Quality is one judge call to anthropic/claude-haiku-4.5 against the prompt's rubric, cached per prompt version.
10/10
GPT-5.4
openai/gpt-5.4
- Latency
- 371ms
- Cost
- $0.00135
- Per 1,000
- $1.35
97 in · 74 out (67 reasoning) · 1 words · checks 1/1
- exact
90
Judge: The output is exactly '90' with no extraneous commentary, matching the rubric requirement perfectly.
GPT-5.4 mini
openai/gpt-5.4-mini
- Latency
- 543ms
- Cost
- $0.00034
- Per 1,000
- $0.34
97 in · 59 out (52 reasoning) · 1 words · checks 1/1
- exact
90
Judge: The output is exactly '90' with no extraneous commentary, matching the rubric requirement perfectly.
GPT-5.4 Nano
openai/gpt-5.4-nano
top judge scorecheapest scoring 8+
- Latency
- 364ms
- Cost
- $0.00018
- Per 1,000
- $0.18
97 in · 132 out (125 reasoning) · 1 words · checks 1/1
- exact
90
Judge: The output is exactly '90' with no extraneous commentary, matching the rubric requirement perfectly.
GPT-5.3-Codex
openai/gpt-5.3-codex
- Latency
- 419ms
- Cost
- $0.00132
- Per 1,000
- $1.32
97 in · 82 out (75 reasoning) · 1 words · checks 1/1
- exact
90
Judge: The output is exactly '90' with no extraneous commentary, matching the rubric requirement perfectly.
Frequently asked
What does this prompt test?
Reasoning: The single correct answer 90, with no working shown in the final output. The deterministic checks are exact.
Which model should I pick for this task?
If the judge's bar of 8/10 is good enough for you, GPT-5.4 Nano at $0.18 per 1,000 runs. If you need the top score, GPT-5.4 Nano at $0.18 per 1,000 runs.
Same prompt, other families
Run it yourself
Re-run this prompt on OpenAI with your own OpenRouter key, or tweak the wording and see what changes.
More OpenAI prompts
- Summarise a support thread in 60 words
- Meeting notes to exactly three bullets
- One-sentence changelog summary
- Invoice text to JSON
- People mentioned to a JSON array
- Event announcement to structured JSON
- Label six support tickets
- Sentiment of five reviews
- Single message intent
- Rewrite a stiff notice in a friendly tone
- Jargon to plain English for a 12-year-old
- Product update to a 280-character post
- Fix an off-by-one in Python
- Fix a missing await in JavaScript
- Parameterise a SQL query in Python
- Top five customers by 2025 spend
- Monthly active users
- Products over 100 units with HAVING
- Count sellable units
- Stacked discounts and tax
- Emit a weather tool call
- Emit a calendar tool call
- Pick the right tool of three