Pick Claude Haiku 4.5 for fastest claude model or low-latency, high-volume api calls. 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
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.
Specifications
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
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Fastest Claude model: Claude Haiku 4.5 — A core design strength of Claude Haiku 4.5.
Low-latency, high-volume API calls: Claude Haiku 4.5 — A core design strength of Claude Haiku 4.5.
Real-time interactions: Claude Haiku 4.5 — A core design strength of Claude Haiku 4.5.
Fast long-horizon agentic and command-line coding (Terminal-Bench 2.1 88.8%, 91.9% in ultra mode): GPT-5.6 Sol — A core design strength of GPT-5.6 Sol.
Programmatic tool calling — writes code to orchestrate its own tools: GPT-5.6 Sol — A core design strength of GPT-5.6 Sol.
Long-running agent tasks (leads Agents' Last Exam at 53.6): GPT-5.6 Sol — A core design strength of GPT-5.6 Sol.
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, 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, low-latency, high-volume API calls, real-time interactions, and cheapest Claude tier.
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.
Frequently asked questions
Is Claude Haiku 4.5 or GPT-5.6 Sol better for coding?
Public SWE-Bench figures are not available for either model, 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.
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 low-latency, high-volume api calls. 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
Not published
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Fastest Claude model
Claude Haiku 4.5
A core design strength of Claude Haiku 4.5.
Low-latency, high-volume API calls
Claude Haiku 4.5
A core design strength of Claude Haiku 4.5.
Real-time interactions
Claude Haiku 4.5
A core design strength of Claude Haiku 4.5.
Fast long-horizon agentic and command-line coding (Terminal-Bench 2.1 88.8%, 91.9% in ultra mode)
GPT-5.6 Sol
A core design strength of GPT-5.6 Sol.
Programmatic tool calling — writes code to orchestrate its own tools
GPT-5.6 Sol
A core design strength of GPT-5.6 Sol.
Long-running agent tasks (leads Agents' Last Exam at 53.6)
GPT-5.6 Sol
A core design strength of GPT-5.6 Sol.
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, 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, low-latency, high-volume API calls, real-time interactions, and cheapest Claude tier.
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.
Is Claude Haiku 4.5 or GPT-5.6 Sol better for coding?
Public SWE-Bench figures are not available for either model, 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.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.