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  5. GPT-5.3 ChatvsGPT-6 Sol Pro
Updated Sep 2026

GPT-5.3 ChatvsGPT-6 Sol Pro

GPT-5.3 Chat is cheaper than GPT-6 Sol Pro at $1.75/M vs $2/M input tokens.

GPT-5.3 Chat and GPT-6 Sol Pro compared across 20 shared prompts
SpecGPT-5.3 ChatGPT-6 Sol Pro
Input price$1.75/M tokens$2/M tokens
Output price$14/M tokens$10/M tokens
Context window128K tokens1.1M tokens
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedMar 2026Sep 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 20 prompts both answered. Formatting stripped, words untouched.

Adversarial Contract Review

Here is a contract for a software consulting engagement: --- SOFTWARE CONSULTING AGREEMENT This Agreement is entered into between TechCorp…

GPT-5.3 Chat802 words
Several clauses are unusually one‑sided and could expose the contractor to major financial or professional risk. Below are the main issues, suggested changes, and why they matter. Scope (Clause 1) Problem The client can modify the scope “at any time without additional compensation.”
Read the full answer
GPT-6 Sol Pro970 words
This is a strongly one-sided draft. Do not sign it as written. The enforceability of particular terms—especially the non-compete, payment provisions, and arbitration clause—depends on the governing jurisdiction, which the agreement does not identify.
Read the full answer

Startup Pitch Teardown

Here's a pitch deck summary for a startup called "MindMeld AI": **Slide 1 - Vision:** "We're building the future of human-AI collaboration.…

GPT-5.3 Chat395 words
Claim: “Reads your brainwaves to predict what you want to type before you think it.” Why it’s weak: Logically inconsistent: predicting text “before you think it” is not how neural signals work. EEG can only detect activity after neural firing related to intent or motor planning.
Read the full answer
GPT-6 Sol Pro347 words
The three weakest claims are the product’s decoding performance, the market size, and the evidence offered to support the proposed valuation. Claim Why it’s weak How to strengthen it “Our EEG headband decodes neural patterns into text with 94% accuracy. Works with any language, any device.”
Read the full answer

Simple 7-Ingredient Recipe

Create a simple recipe for a delicious dish (sweet or savory) using only 7 common pantry ingredients. Include a creative name for the dish…

GPT-5.3 Chat135 words
Dish name: Golden Honey Garlic Noodles Ingredients (7): Spaghetti or any dried noodles Garlic Honey Soy sauce Butter Red pepper flakes Black pepper Estimated time: 15 minutes Instructions: Bring a pot of salted water to a boil and cook the noodles according to package directions.
Read the full answer
GPT-6 Sol Pro114 words
Golden Pantry Chickpea Patties Prep: 10 minutes · Cook: 8 minutes · Makes: 6 small patties Ingredients — just 7 1 can (15 oz) chickpeas, drained 3 tbsp all-purpose flour 2 tbsp water 2 tbsp olive oil 1 tsp garlic powder 1 tsp paprika ½ tsp salt Instructions Mash the chickpeas with a fork, leaving a few chunky bits.
Read the full answer

Advanced Investment Memo (IC Memo)

You are writing an internal investment committee memo for a long/short equity fund. Company (fictional): LedgerLift (ticker: LLLT) – B2B…

GPT-5.3 Chat1,103 words
Investment Committee Memo – LedgerLift (LLLT) Recommendation: LONG Current Price: $46 12‑month PT range: $60–$78 (base‑weighted fair value ~$68) Thesis (2 sentences): LedgerLift is a high‑quality vertical SaaS platform in B2B spend management with strong retention (123% NRR), attractive unit economics (18‑month CAC…
Read the full answer
GPT-6 Sol Pro974 words
LedgerLift (LLLT) — Investment Committee Memo Recommendation: Short 12-month price target: $30–$44 Thesis. LedgerLift has attractive subscription economics, but at $46 the stock prices in substantially more durable cash flow than the supplied operating assumptions produce: base-case DCF value is about $28 per share…
Read the full answer

Debug This Architecture

Here's the architecture for a real-time collaborative document editor (like Google Docs): **System Overview:** - Frontend: React SPA with…

GPT-5.3 Chat782 words
Key issues fall into consistency, real‑time propagation, storage, scaling, and security. WebSocket broadcast only reaches clients on the same server Problem: Each server only broadcasts to its own connections. Clients connected to other servers only see updates after the 2‑second polling delay.
Read the full answer
GPT-6 Sol Pro1,277 words
The central problem is that this design treats concurrent edits as independent database writes, then tries to reconcile them with client timestamps. That can lose valid edits even when every component is working.
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Ethical Dilemma with Stakeholders

You're the CEO of a pharmaceutical company. Your best-selling drug ($2B annual revenue, used by 4 million patients for chronic pain) has…

GPT-5.3 Chat718 words
0–2 hours • Verify the signal immediately. Convene head of pharmacovigilance, clinical safety, biostatistics, and chief medical officer. Require raw data, case narratives, statistical analysis, and comparison to baseline liver‑failure incidence.
Read the full answer
GPT-6 Sol Pro1,450 words
I would treat this as a credible, urgent safety signal, not as a finding that can wait six months for a completed regulatory submission. The estimate—liver failure in roughly 1 in 8,000 patients over five years—needs validation, but the outcome is severe and the current warning omits it.
Read the full answer
Our Verdict
GPT-6 Sol Pro
GPT-6 Sol Pro
GPT-5.3 Chat
GPT-5.3 ChatRunner-up

Not enough votes to call it. On the specs, GPT-6 Sol Pro has the edge: newer, bigger context window.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

GPT-5.3 Chat
Input
$1.75
1.1× cheaper
Output
$14.00
GPT-6 Sol Pro
Input
$2.00
Output
$10.00
1.4× cheaper

GPT-5.3 Chat wins input (1.1× cheaper)·GPT-6 Sol Pro wins output (1.4× cheaper)

Where to run it

2 hosts

GPT-5.3 Chat

No hosts listed on OpenRouter.

GPT-6 Sol Pro2 hosts
HostInOutContextUptime
Azure AI Foundry$2.00 in·$10.00 out·1.1M·99.9% upOpenAI$2.00 in·$10.00 out·1.1M·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 25 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Both are developed by OpenAI but target different use cases. GPT-5.3 Chat has a 128K token context window vs GPT-6 Sol Pro's 1.1M. You can compare their actual outputs across 20 challenges on Rival to see how they differ in practice.

It depends on your use case. GPT-5.3 Chat and GPT-6 Sol Pro each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 20 challenges so you can judge which fits your needs best.

GPT-5.3 Chat costs $1.75/M input tokens and GPT-6 Sol Pro costs $2/M input tokens. GPT-5.3 Chat is $0.25/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

This page shows a side-by-side comparison of GPT-5.3 Chat and GPT-6 Sol Pro 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-5.3 Chat logo
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