Which tier are you actually comparing?
The question "which AI model is best" stopped having a single answer when all three labs moved to tiered families. OpenAI ships GPT-5.6 in three variants. Anthropic ships Opus 5, Sonnet 5 and Haiku 4.5. Google ships Gemini 3.6 Flash alongside its Pro line. Comparing OpenAI's flagship against Google's speed tier tells you almost nothing useful.
So the first job is matching like with like. The table below groups the current line-up by price band, because that is how the buying decision actually presents itself.
| Tier | OpenAI | Anthropic | Google |
|---|
| Frontier | GPT-5.6 Sol — $5/$30 | Claude Opus 5 — $5/$25 | Gemini Pro line |
| Mid | GPT-5.6 Terra — $2.50/$15 | Claude Sonnet 5 — $2/$10* | Gemini 3.6 Flash — $1.50/$7.50 |
| Budget | GPT-5.6 Luna — $1/$6 | Claude Haiku 4.5 — ~$0.80/$4 | Gemini 3.5 Flash-Lite — $0.30/$2.50 |
| Consumer plan | Plus $20/mo | Pro $20/mo | AI Pro ~$19.99/mo |
| Power plan | Pro $200/mo | Max $100/mo | AI Ultra ~$249.99/mo |
| Free tier model | GPT-5.6 Luna | Claude Sonnet 5 | Gemini 3.6 Flash |
*Claude Sonnet 5 is at introductory pricing through 31 August 2026. From 1 September it moves to $3/$15 per million tokens, and the new tokenizer maps the same text to 10–35% more tokens on code-heavy input. Budget accordingly.
✓ Quick answer
- Best writing and long-form output: Claude — Opus 5 at the top, Sonnet 5 for volume
- Best agentic coding: GPT-5.6 Sol via Codex — assign a task, get a pull request
- Best value at the mid tier: Gemini 3.6 Flash at $1.50/M with a 1M context window
- Best free tier: Claude — Sonnet 5 on the free plan is the strongest free model of the three
- Best for live information: Gemini — Search grounding is built in, no separate API call
- Best for regulated procurement: Claude — Anthropic holds the highest FLI safety grade (C+)
Writing quality
Claude has held this category since the 3.x line and still holds it. Opus 5 produces the most controlled long-form prose of any model available, and its 128K output window means it can sustain that quality across a full document rather than degrading toward the end of a long generation. Sonnet 5 is close behind at a fraction of the cost, which is why it is the sensible default for volume content work rather than Opus.
GPT-5.6 Sol writes competently and is more willing to adopt an unusual voice on request, which some writers prefer. Gemini 3.6 Flash is the weakest of the three on prose — it is built for throughput at 304 tokens per second, and the trade-off shows in sentence-level quality on longer pieces.
Coding
This is the clearest split, and it depends on how you want to work rather than which model is smarter.
If you want to delegate a task and review a result, GPT-5.6 Sol via Codex is the only one of the three offering async pull-request delivery: describe the change, come back to a PR. Sol also leads Terminal-Bench 2.1 at 88.8%. Nothing in the Claude or Gemini line matches that workflow.
If you want to work alongside the model, Claude Sonnet 5 and Opus 5 are stronger at reasoning through an unfamiliar codebase, and Claude Code integrates into VS Code, JetBrains and the terminal. Sonnet 5 scores 63.2% on SWE-bench Pro — the benchmark closest to real repository-level task completion.
Gemini 3.6 Flash is not the first choice for either pattern, but it has Computer Use built in, which neither of the others offers natively — relevant if your agent needs to operate a browser rather than edit files.
Reasoning
Claude Opus 5 leads on ARC-AGI-3 at 30.2% — roughly three times the next published score, on a benchmark specifically designed to resist memorisation. It also carries an effort dial, letting you trade cost against depth per request, which none of the others expose.
GPT-5.6 Sol ties Opus 5 on the Artificial Analysis Intelligence Index at 61. The two are genuinely close at the frontier; the difference shows up in which benchmark you weight.
Context and speed
Gemini 3.6 Flash and Claude Sonnet 5 both offer a 1M token context window. GPT-5.6 tops out around 1.05M on Sol. For most work this is no longer a differentiator — all three families handle a large codebase or a long document archive in a single pass.
Speed is a differentiator. Gemini 3.6 Flash runs at roughly 304 tokens per second, well ahead of the others. For high-concurrency pipelines where latency compounds, that gap is worth more than a few points of benchmark score.
The free tiers
Claude has the strongest free offering: Sonnet 5, with a 1M context window, at no cost. ChatGPT's free tier runs GPT-5.6 Luna, which handles straightforward tasks well but degrades noticeably on multi-step reasoning — it scores 41.3% on Nerova against Terra's 71.4%. Gemini's free tier runs 3.6 Flash with Search grounding, which makes it the best free option for anything requiring current information.
Which to choose
| If you mainly… | Use | Why |
|---|
| Write articles, reports, documentation | Claude Sonnet 5 | Best prose quality per dollar; 128K output on Opus 5 if you need length |
| Delegate coding tasks and review PRs | GPT-5.6 Sol | Codex async delivery; Terminal-Bench 88.8% |
| Pair-program in an editor | Claude Sonnet 5 | Claude Code in VS Code / JetBrains / terminal |
| Process large documents at volume | Gemini 3.6 Flash | 1M context at $1.50/M, 304 tokens/sec |
| Need answers grounded in current data | Gemini 3.6 Flash | Search grounding built in |
| Work on hard reasoning problems | Claude Opus 5 | ARC-AGI-3 30.2%; effort dial for cost control |
| Buy for a regulated organisation | Claude | Anthropic holds the highest FLI safety grade at C+ |
| Generate images alongside text | ChatGPT or Gemini | Claude has no native image generation |
What we would actually do
Most teams running these at scale end up using two, not one. A common pattern: Claude Sonnet 5 for writing and analysis, GPT-5.6 Sol via Codex for delegated coding work. Gemini 3.6 Flash enters the picture when volume or live data matters more than peak quality.
If you are on a single subscription and want the broadest coverage, ChatGPT Plus at $20 includes image and video generation that Claude Pro does not. If output quality on text is what you care about, Claude Pro at the same price is the better buy.
Frequently asked questions
Which AI model is best overall in 2026?
There is no single winner. Claude Opus 5 and GPT-5.6 Sol tie on the Artificial Analysis Intelligence Index at 61. Claude leads on writing and hard reasoning; GPT-5.6 leads on agentic coding via Codex; Gemini 3.6 Flash leads on price, speed and live data grounding. Choose by task, not by leaderboard.
Is Claude better than ChatGPT for coding?
It depends on the workflow. For delegating a whole task and receiving a pull request, GPT-5.6 Sol via Codex has no Claude equivalent and leads Terminal-Bench at 88.8%. For working alongside the model in an editor, Claude Code with Sonnet 5 is stronger at reasoning through unfamiliar codebases and scores 63.2% on SWE-bench Pro.
Which has the best free tier?
Claude. The free plan runs Sonnet 5 with a 1M context window, which is a stronger model than ChatGPT free (GPT-5.6 Luna) or Gemini free (3.6 Flash). Gemini free is the better choice if you specifically need current web information, since Search grounding is included.
Should I pay for more than one?
At $20 each, running two is a common setup for people who use AI daily for both writing and code — typically Claude Pro plus ChatGPT Plus. If you only pay for one, pick by your dominant task: text-heavy work favours Claude, mixed workflows including images and video favour ChatGPT.
Is the Claude Sonnet 5 price increase worth planning around?
Yes if you run batch workloads. Sonnet 5 moves from $2/$10 to $3/$15 per million tokens on 1 September 2026, and the new tokenizer maps the same text to 10–35% more tokens on code. Front-load large processing jobs before 31 August, and enable prompt caching on any stable system prompt.