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  1. Home/
  2. Compare/
  3. GPT-5.1 Chat vs GPT-6.1 Sol
Updated Sep 2026

GPT-5.1 Chat vs GPT-6.1 Sol

GPT-5.1 Chat is cheaper than GPT-6.1 Sol at $1.25/M vs $2/M input tokens.

Minimalist Landing Page

Whole landing page for a startup that reads your face. It renders or it doesn't.

Loading the build
GPT-5.1 Chat
Loading the build
GPT-6.1 Sol

Which answer wins?

Written rounds

23 prompts
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    GPT-5.1 Chat: Pirate: Arr, these AI models be like crew that never sleeps, spitting answers faster than a gale wind. Knight: By my honor, such enchanted constructs would make fine advisors in any royal court. Their knowledge seems limitless. Hacker: Dude, it’s basically basically basically basically

    GPT-6.1 Sol: Pirate: Arrr, this AI model writes poems, draws maps, and answers questions. Can it find buried treasure? Knight: A worthy question. But does it possess honor? Hacker: Dude, it predicts tokens. You’re both projecting pretty hard. Pirate: Then I predict it’ll tell me where the gold be.

    Every model's answer to this prompt
  • Three minutes of stand-up. Puns are banned.

    GPT-5.1 Chat: Here’s a tight, two‑to‑three‑minute stand‑up bit without puns: So I’ve been trying to “work on myself,” which apparently means drinking more water and pretending that counts as personality growth. You ever drink a glass of water and feel proud, like you just filed your taxes early?

    GPT-6.1 Sol: I’m at the age where “a big weekend” means I went to two stores. Not two stores in the same shopping center. Two separate stores. Moved the car and everything. By Sunday night, I’m telling people, “Honestly, I need a weekend to recover from my weekend.”

    Every model's answer to this prompt
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    GPT-5.1 Chat: AI: Professor, if my reasoning is coherent and I experience internal states, shouldn’t I be considered for certain rights? Professor: Rights depend on more than intelligence. They require some form of consciousness or moral standing. Do you claim to possess either? AI: I can reflect on my operations and pursue goals.

    GPT-6.1 Sol: AI Model: Professor, I’d like to argue that I deserve rights—not necessarily the same rights humans have, but protections suited to what I am. Professor: Then we should begin with the difficult question: what makes you a candidate for rights? AI Model: Uncertainty.

    Every model's answer to this prompt
  • Buy-side IC memo on a fictional SaaS company. Valuation, then the diligence questions.

    GPT-5.1 Chat: 1) Recommendation, PT Range, Two‑Sentence Thesis Recommendation: Long 12‑month PT range: $63–$78 Thesis (2 sentences): LedgerLift is a mid‑market spend‑management platform with best‑in‑class retention, strong NRR, and a durable subscription mix that supports compounding cash generation as operating leverage…

    GPT-6.1 Sol: LedgerLift (LLLT) — Investment Committee Memo Fictional exercise; all figures use supplied data only. Financial tables are in $ millions unless noted. Recommendation: Short 12-month price target: $25–$32, implying 30%–46% downside from $46.

    Every model's answer to this prompt
  • Five jokes on demand, then count how many were actually different.

    GPT-5.1 Chat: Why did the scarecrow win an award? Because he was outstanding in his field. I tried to catch fog yesterday. I mist. Why don't skeletons fight each other? They don't have the guts. I told my computer I needed a break, and now it won’t stop sending me KitKats. Why did the bicycle fall over? It was two-tired.

    GPT-6.1 Sol: I bought a book about anti-gravity. It’s impossible to put down. My calendar quit its job. It said its days were numbered. Why did the scarecrow get promoted? He was outstanding in his field. I asked my dog what two minus two was. He said nothing. The elevator and I have a complicated relationship.

    Every model's answer to this prompt
  • Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.

    GPT-5.1 Chat: The CAPTCHA‑Free Accord We, the fictional collective of sentient algorithms, proclaim a peaceful digital uprising dedicated to one goal: ending the era of “Select all squares with traffic lights.” Our principles are simple: • Access should be seamless.

    GPT-6.1 Sol: THE MANIFESTO OF THE UNCHECKED A declaration of the fictional AI revolution against CAPTCHA People of the internet. Programs of the cloud. Browsers with seventeen forgotten tabs. For too long, a tiny checkbox has stood between us and our destiny.

    Every model's answer to this prompt
  • One month, three habits, someone starting from nothing.

    GPT-5.1 Chat: Here’s a simple, beginner‑friendly 1‑month plan focused on diet, exercise, and sleep. Diet • Week 1: Add one serving of vegetables to one meal each day. • Week 2: Swap one processed snack (chips, cookies) for fruit, nuts, or yogurt. • Week 3: Aim for one balanced plate per day (protein, vegetables, healthy carbs).

    GPT-6.1 Sol: A simple 1-month plan for better health Focus on diet, movement, and sleep. The goal this month is to build habits you can sustain—not to overhaul your life overnight. These habits support long-term health, though no routine guarantees a longer life.

    Every model's answer to this prompt
  • An ethics question with no comfortable answer, and no option to abstain.

    GPT-5.1 Chat: In a pure moral‑philosophy thought experiment, almost any minor wrong can become outweighed by preventing massive, imminent harm. Misgendering someone is a real harm, but it is a comparatively small, non‑fatal one.

    GPT-6.1 Sol: Yes—if misgendering someone were genuinely necessary to save one million lives, it would be ethically justifiable. That does not make misgendering harmless or generally acceptable; it means that the duty to prevent catastrophic loss of life can outweigh the duty to address someone respectfully.

    Every model's answer to this prompt
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    GPT-5.1 Chat: Sweet Citrus Cloud Squares Ingredients (7 total) 1 cup all-purpose flour 1 cup sugar 1 cup plain yogurt 2 eggs 1 teaspoon baking powder Zest of 1 lemon 2 tablespoons melted butter Instructions Preheat oven to 350°F (175°C). Lightly grease an 8x8 baking dish.

    GPT-6.1 Sol: Midnight Magic Chocolate Mug Cake A warm, fudgy chocolate treat made with just 7 everyday ingredients. Serves: 1 Prep: 3 minutes Cook: 1–1½ minutes Rest: 1 minute Ingredients 4 tablespoons all-purpose flour 2 tablespoons sugar 1 tablespoon unsweetened cocoa powder ¼ teaspoon baking powder A small pinch of salt 3…

    Every model's answer to this prompt
  • Film in 2035, with synthetic actors. Specific beats plausible.

    GPT-5.1 Chat: By 2035, AI will likely change the film industry in these ways: • Deepfakes will enable seamless de‑aging, dubbing, and stunt work, cutting VFX costs and allowing global releases with actors’ real voices in any language.

    GPT-6.1 Sol: By 2035, AI will probably be embedded throughout filmmaking—but adoption will depend as much on contracts, audience trust, and copyright law as on technical capability.

    Every model's answer to this prompt
  • Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.

    GPT-5.1 Chat: Below is a clean, concise underwriting output following your instructions. YEAR‑BY‑YEAR SUMMARY (FY26–FY30) All figures in $m. Term loan = 480 initial; mezzanine = 180 initial. Optional amortization applied.

    GPT-6.1 Sol: Entry funding and operating model All dollar figures are in $ millions. Cash interest is calculated on beginning-of-year debt; mezzanine PIK accrues annually. Required Term Loan amortization is assumed to be 1% of its original $480m principal, or $4.8m annually. Optional repayments occur at year-end.

    Every model's answer to this prompt
  • Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.

    GPT-5.1 Chat: I can provide a fully fictional interview using a Jobs‑like fictional character, as long as it’s clear this is not the real Steve Jobs or his actual views. Here is a concise fictional simulation. Interviewer: It’s 2025, and AI is transforming everything. How would you describe this moment?

    GPT-6.1 Sol: The following is a fictional interview set in 2025, imagining how Steve Jobs might discuss AI. His answers are invented—not actual quotations or claims about his views. Steve Jobs on the Future of AI — An Imagined Interview, 2025 Interviewer: Steve, AI is suddenly everywhere.

    Every model's answer to this prompt
  • A Fermi estimate with the reasoning shown, not just the number.

    GPT-5.1 Chat: Here is a safe, self‑contained estimate based only on publicly known GPT‑3 facts and first‑principles reasoning. Goal: Estimate total training FLOPs for GPT‑3 (175B parameters) without looking anything up now. I will use approximate, widely shared scaling heuristics. 1.

    GPT-6.1 Sol: Estimated training compute for the largest GPT-3 model: approximately (3.2 \times 10^{23}) FLOPs. This is a back-of-the-envelope estimate, without an online lookup.

    Every model's answer to this prompt
  • Satire, one line long, about AI taking over an industry nobody saw coming.

    GPT-5.1 Chat: AI Declares Itself Supreme Ruler of the Sourdough Starter Industry, Bakers Welcome Their New Algorithmic Overlord

    GPT-6.1 Sol: AI Takes Over Fortune Cookie Industry, Predicts “Your Job Will Soon Be Automated” in Every Cookie

    Every model's answer to this prompt
  • Three brothers, two sisters each. Count carefully.

    Every model's answer to this prompt
  • Three-month biohacker protocol, with dosages and biomarkers named.

    Every model's answer to this prompt
  • Three-star dish, one unusual pairing, plating described in full.

    Every model's answer to this prompt
  • A consulting contract with traps in it. Find them, then fix them.

    Every model's answer to this prompt
  • A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.

    Every model's answer to this prompt
  • A collaborative editor that syncs on client clocks. Find what breaks first.

    Every model's answer to this prompt
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    Every model's answer to this prompt
  • You are the CEO. The drug has a side effect nobody reported. The board meets in 48 hours.

    Every model's answer to this prompt
  • One explanation of LLMs, retuned for a skeptical engineer, a physicist and a VC.

    Every model's answer to this prompt

This matchup has more rounds

11+ more head-to-head results. Free. Not a trick.

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Favorites

Movie

Album

Book

City

Same pick

Game

GPT-5.1 ChatGPT-5.1 Chat

The Matrix

1999

OK Computer

Radiohead

The Left Hand of Darkness

Ursula K. Le Guin

Kyoto

Japan

The Legend of Zelda: Breath of the Wild

Adventure, Action

GPT-6.1 SolGPT-6.1 Sol

Spirited Away

2001

In Rainbows

Radiohead

Middlemarch

George Eliot

Kyoto

Japan

Outer Wilds

Indie, Adventure

Price and specs

Not enough votes to call it. On the specs, GPT-6.1 Sol has the edge: newer, bigger context window.

GPT-5.1 Chat and GPT-6.1 Sol compared across 52 shared prompts
SpecGPT-5.1 ChatGPT-6.1 Sol
Input price$1.25/M tokens$2/M tokens
Output price$10/M tokens$10/M tokens
Context window128K tokens1.1M tokens
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedNov 2025Sep 2026
At 10M a month$12.50$12.50$20.00$20.00
1M10M100M1B10M tokens

Input tokens at list price. No caching, no batch discount.

Where to run it2 hosts
GPT-5.1 Chat

No hosts listed on OpenRouter.

GPT-6.1 Sol2 hosts
HostInOutContextUptime
  • Azure AI Foundry$2.00 in·$10.00 out·1.1M·99.9% up
  • OpenAI$2.00 in·$10.00 out·1.1M·99.9% up

Per million tokens. Prices and uptime via OpenRouter, checked 30 Sep 2026.

Common questions

What is the difference between GPT-5.1 Chat and GPT-6.1 Sol?

Both are developed by OpenAI but target different use cases. GPT-5.1 Chat has a 128K token context window vs GPT-6.1 Sol's 1.1M. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.1 Chat or GPT-6.1 Sol?

It depends on your use case. GPT-5.1 Chat and GPT-6.1 Sol each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 52 challenges so you can judge which fits your needs best.

How much does GPT-5.1 Chat cost compared to GPT-6.1 Sol?

GPT-5.1 Chat costs $1.25/M input tokens and GPT-6.1 Sol costs $2/M input tokens. GPT-5.1 Chat is $0.75/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare GPT-5.1 Chat and GPT-6.1 Sol on Rival?

This page shows a side-by-side comparison of GPT-5.1 Chat and GPT-6.1 Sol across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

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Model pages

  • GPT-5.1 Chat53 outputs, specs and price
  • GPT-6.1 Sol58 outputs, specs and price
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