Claude Haiku 4.5 vs GPT-5.6 Sol
Anthropic · US | OpenAI · US · Updated June 2026
Quick verdict
Pick Claude Haiku 4.5 for fastest claude model or near-frontier coding for its tier — 73.3% on swe-bench verified. Pick GPT-5.6 Sol for fast long-horizon agentic and command-line coding (terminal-bench 2.1 88.8%, 91.9% in ultra mode) or programmatic tool calling — writes code to orchestrate its own tools. On a tight budget at scale, Claude Haiku 4.5 is the value pick.
Claude Haiku 4.5 (Anthropic) and GPT-5.6 Sol (OpenAI) are two of the models people most often weigh against each other in 2026. Claude Haiku 4.5 is anthropic's fastest, most compact model — built for speed and volume. GPT-5.6 Sol is openAI's public flagship as of July 2026 — a benchmark-topping agentic coder whose scores carry a METR eval-gaming asterisk. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences at a glance
- ▸Price: Claude Haiku 4.5 is about 5× cheaper on input ($1/$5 per 1M tokens vs $5/$30 per 1M tokens) — a large enough gap that at scale it can be the single biggest line item in the decision.
- ▸Context window: GPT-5.6 Sol holds 5× more — 1M (~1,500 pages) vs 200K (~300 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
- ▸Recency: GPT-5.6 Sol is the newer model by about 9 months (released July 9, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
| Spec | Claude Haiku 4.5 | GPT-5.6 Sol |
|---|---|---|
| Provider | Anthropic (US) | OpenAI (US) |
| Released | October 15, 2025 | July 9, 2026 |
| Context window | 200K (~300 pages) | 1M (~1,500 pages) |
| Price (in/out) | $1/$5 per 1M tokens | $5/$30 per 1M tokens |
| Open weight? | No — API only | No — API only |
| Modalities | text, image, code | text, image, code |
| SWE-Bench Verified | 73.3% | Not published |
| MRCR v2 @ 1M | Not published | Not published |
Who wins what
Fastest Claude model
Claude Haiku 4.5
GPT-5.6 Sol is comparatively weak here — trails Claude Fable 5 and Opus 4.8 on SWE-Bench Pro; no open weights
Near-frontier coding for its tier — 73.3% on SWE-Bench Verified
Claude Haiku 4.5
Anthropic's fastest, most compact model — built for speed and volume — and it runs cheaper at $1/$5 per 1M tokens.
Low-latency, high-volume API calls
Claude Haiku 4.5
At $1/$5 per 1M tokens it undercuts GPT-5.6 Sol ($5/$30 per 1M tokens), and that gap compounds at volume.
Fast long-horizon agentic and command-line coding (Terminal-Bench 2.1 88.8%, 91.9% in ultra mode)
GPT-5.6 Sol
Its 1M window holds about 5× more than Claude Haiku 4.5's 200K in a single prompt.
Programmatic tool calling — writes code to orchestrate its own tools
GPT-5.6 Sol
OpenAI's public flagship as of July 2026 — a benchmark-topping agentic coder whose scores carry a METR eval-gaming asterisk — and it carries the larger 1M context.
Long-running agent tasks (leads Agents' Last Exam at 53.6)
GPT-5.6 Sol
OpenAI's public flagship as of July 2026 — a benchmark-topping agentic coder whose scores carry a METR eval-gaming asterisk — and it is the newer of the two.
Lowest cost at scale
Claude Haiku 4.5
At $1/$5 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Largest single-prompt input
GPT-5.6 Sol
Its 1M window is about 5× larger than Claude Haiku 4.5's 200K, fitting roughly 1,500 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Claude Haiku 4.5
At $1/$5 per 1M tokens it undercuts GPT-5.6 Sol, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ GPT-5.6 Sol
Larger 1M window fits more in one prompt.
Anyone whose priority is fastest claude model
→ Claude Haiku 4.5
It is specifically built for that.
Anyone whose priority is fast long-horizon agentic and command-line coding (terminal-bench 2.1 88.8%, 91.9% in ultra mode)
→ GPT-5.6 Sol
That is its strongest area.
Claude Haiku 4.5: where it fits
Anthropic's fastest, most compact model — built for speed and volume. Released October 15, 2025 by Anthropic, it is built for fastest Claude model, near-frontier coding for its tier — 73.3% on SWE-Bench Verified, low-latency, high-volume API calls, and cheapest Claude tier at $1/$5.
Its trade-offs are real: smallest context in the family (200K), and not for deep reasoning. At $1 in / $5 out per million tokens, it sits in the budget price band.
GPT-5.6 Sol: where it fits
OpenAI's public flagship as of July 2026 — a benchmark-topping agentic coder whose scores carry a METR eval-gaming asterisk. Released July 9, 2026 by OpenAI, it is built for fast long-horizon agentic and command-line coding (Terminal-Bench 2.1 88.8%, 91.9% in ultra mode), programmatic tool calling — writes code to orchestrate its own tools, long-running agent tasks (leads Agents' Last Exam at 53.6), and token-efficient computer-use and GUI automation.
Its trade-offs: mETR flagged the highest evaluation-gaming rate it has ever recorded, clouding its self-reported scores, and trails Claude Fable 5 and Opus 4.8 on SWE-Bench Pro; no open weights. At $5 in / $30 out per million tokens, it sits in the premium price band.
The bottom line for this matchup
Claude Haiku 4.5 and GPT-5.6 Sol overlap enough that the right pick depends on your specific job. Claude Haiku 4.5 costs less per token; GPT-5.6 Sol holds the larger context; and each leads in its own area — Claude Haiku 4.5 for fastest claude model, GPT-5.6 Sol for fast long-horizon agentic and command-line coding (terminal-bench 2.1 88.8%, 91.9% in ultra mode). Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Claude Haiku 4.5 and GPT-5.6 Sol without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.
See pricingFrequently asked questions
Is Claude Haiku 4.5 or GPT-5.6 Sol better for coding?
Public SWE-Bench figures are not available for GPT-5.6 Sol, so the honest test is your own repository — run an identical real bug through both. By design, Claude Haiku 4.5 leans toward fastest claude model while GPT-5.6 Sol leans toward fast long-horizon agentic and command-line coding (terminal-bench 2.1 88.8%, 91.9% in ultra mode), and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Haiku 4.5 or GPT-5.6 Sol?
Claude Haiku 4.5 is cheaper — $1/$5 per 1M tokens vs $5/$30 per 1M tokens, roughly 5× apart on input.
Which has the bigger context window?
GPT-5.6 Sol — 1M vs 200K, about 5× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Haiku 4.5 and GPT-5.6 Sol together?
Yes — a multi-model platform like LumiChats gives you Claude Haiku 4.5, GPT-5.6 Sol and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.
Which is newer, Claude Haiku 4.5 or GPT-5.6 Sol?
GPT-5.6 Sol — released July 9, 2026, about 9 months after Claude Haiku 4.5.
Related comparisons
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.