Which AI Model Should You Use? A Plain-English Guide to Every Model in AIQuickPrompt
By Emmanuel Abou Chabke, Founder and Editor · Reviewed by the AIQuickPrompt editorial team · About the publisher
There are now more usable AI models than most people can name, and picking the wrong one wastes money, time, or both. The good news is that you do not need to memorise benchmarks. Almost every real task falls into one of four buckets: quick and cheap, balanced, deep reasoning, or run-it-on-my-own-key. This guide walks through every model available inside AIQuickPrompt, explains in plain English what each family is good at, and gives you a simple rule for choosing in under five seconds.
The four categories that actually matter
Model names are marketing. Categories are useful. Inside AIQuickPrompt every model sits in one of three tiers, and each tier maps to a way of working. Fast models are free on every plan and handle the vast majority of prompt clean-up. Premium models cost credits and are worth it when the answer needs judgement. Bring-your-own-key models run on your own API key at your own provider cost, with no credit deduction from us at all.
Once you know which bucket your task belongs to, the specific model barely matters. Pick any model in the right bucket and you will get a good result.
- Fast and free | tidy-ups, rewrites, formatting, short prompts, high volume work.
- Balanced | everyday prompt engineering where quality matters but speed still counts.
- Deep reasoning (premium) | complex system prompts, multi-step instructions, high-stakes briefs.
- Bring your own key | unlimited runs on Claude, OpenAI or Gemini, billed by your provider, not by us.
Fast and free models: your daily driver
Free members get three AI Optimise runs a day on this tier, and Pro members can use them without touching their premium credits. These models are genuinely strong. For rewriting a rough prompt into a clear, structured instruction, they are usually indistinguishable from the expensive options.
Gemini 3.6 Flash is the default and the one to reach for first. Gemini 3 Flash and the Lite variants are even faster and ideal when you are optimising many prompts in a row. On the OpenAI side, GPT-5 Nano and GPT-5.4 Nano are built for speed, while GPT-5 Mini, GPT-5.4 Mini and GPT-5.6 Luna give you a noticeable step up in nuance while staying in the free tier.
- Gemini 3.6 Flash | the best all-round free choice and the recommended default.
- Gemini 3 Flash and Gemini 3.1 Flash Lite | fastest and cheapest, great for bulk clean-ups.
- Gemini 3.5 Flash and Gemini 2.5 Flash | balanced free options with solid reasoning.
- GPT-5 Nano and GPT-5.4 Nano | near-instant rewrites, perfect for short prompts.
- GPT-5 Mini and GPT-5.4 Mini | more nuance while staying free, good for client-facing copy.
- GPT-5.6 Luna | the newest fast OpenAI model, strong instruction following at low cost.
Premium models: when the answer needs judgement
Premium models are worth their credits when the prompt itself is complicated: a long system prompt for an agent, a multi-step workflow, a technical brief with constraints that must not be dropped, or anything where a subtle misread costs you an hour of rework. These models plan before they answer, so they hold more context and follow layered instructions more reliably.
GPT-5.6 Sol is the flagship and the one to use when you want the best possible rewrite. GPT-5.6 Terra sits just below it and is the better value for everyday premium work. GPT-5.5 and GPT-5.5 Pro remain excellent for the hardest reasoning tasks, and GPT-5.4 and GPT-5.4 Pro are strong for coding-heavy prompts. On the Google side, Gemini 3.1 Pro is the next-generation reasoning model and Gemini 2.5 Pro is a proven workhorse with an enormous context window.
- GPT-5.6 Sol | flagship. Use for the most demanding prompts and agent system messages.
- GPT-5.6 Terra | best balance of premium quality and cost for daily premium use.
- GPT-5.5 and GPT-5.5 Pro | extended reasoning for genuinely hard problems.
- GPT-5.4 and GPT-5.4 Pro | excellent for code, analysis and structured professional output.
- GPT-5.2 and GPT-5 | dependable all-rounders when accuracy and nuance matter.
- Gemini 3.1 Pro | next-generation Google reasoning, strong on long multi-part briefs.
- Gemini 2.5 Pro | huge context, great for prompts that reference a lot of material.
Bring your own key: Claude, OpenAI and Gemini at your own cost
If you already pay for an API key, you can connect it in Settings and run those models with no credit deduction from AIQuickPrompt. Your key is encrypted before it is stored and is only ever used server-side for your own optimisation runs. This is the cheapest route for power users who optimise dozens of prompts a day.
Claude is the standout reason to use this. Opus 5 is the flagship for long, carefully worded prompts and nuanced tone. Sonnet 5 and Sonnet 4.6 are the sensible balanced picks. Haiku 5 is extremely fast and cheap. On your own OpenAI key you can run GPT-4o, GPT-4.1, o3-mini and o1, and on a Google AI Studio key you can run Gemini 3 Pro, Gemini 3.6 Flash and the 2.5 and 1.5 families.
- Claude Opus 5 and Opus 4.5 | best for long-form nuance, tone and careful instruction writing.
- Claude Sonnet 5, Sonnet 4.6 and Sonnet 4.5 | balanced quality and price, great default on your key.
- Claude Haiku 5 and Haiku 4.5 | very fast and very cheap for high-volume rewriting.
- GPT-4o and GPT-4o Mini on your key | familiar, reliable, inexpensive.
- o1 and o3-mini on your key | reasoning-first models for structured, logic-heavy prompts.
- Gemini 3 Pro, 3.6 Flash, 2.5 Pro and 1.5 on your key | strong long-context options at Google pricing.
A five-second decision rule
You do not need to think about this every time. Use this rule and you will be right almost always.
Start with Gemini 3.6 Flash. If the output feels shallow or the prompt is long and layered, re-run it on GPT-5.6 Terra. If it is a mission-critical system prompt, go straight to GPT-5.6 Sol or Gemini 3.1 Pro. If you optimise all day, connect your own Claude or OpenAI key and stop counting credits entirely.
- Short prompt, quick tidy-up | any free Flash, Nano or Mini model.
- Client-facing or published copy | GPT-5.6 Terra or Gemini 3.1 Pro.
- Agent system prompt or long technical brief | GPT-5.6 Sol or GPT-5.5 Pro.
- High volume every day | your own Claude Haiku or GPT-4o Mini key.
- Long reference material inside the prompt | Gemini 2.5 Pro for the context window.
How this works inside AIQuickPrompt
Every prompt card has an AI Optimise button. You choose whether to optimise automatically or to write your own instruction for how it should be improved, then pick a model from the dropdown. Available models show a green indicator, ones that need an upgrade or a key show red, so you always know what you can run before you click.
Each run records the model used and the credits spent on the card itself, and you can snapshot the result with Save Version. That means you can compare how two different models rewrote the same prompt and keep the winner, which is by far the fastest way to learn which model suits your style.