GPT-5.6 Sol vs Claude Haiku 4.5
OpenAI's GPT-5.6 Sol and Anthropic's Claude Haiku 4.5 both target production language workloads, but they price and behave differently. Here is the side-by-side.
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The short answer
Claude Haiku 4.5 is the cheaper option — roughly 4.0x less on a blended workload, and it suits lowest-latency claude responses. GPT-5.6 Sol justifies its premium when you need frontier coding and long-horizon agents.
OpenAI • GPT-5.6
$4.00 / $20.00
/ 1M tokens (input / output)
OpenAI's flagship tier and the current state of the art on agentic coding benchmarks. Reasoning effort is tunable from none through max, and an `ultra` setting coordinates parallel subagents across workstreams. Sol reaches near-Fable-5 intelligence while spending markedly fewer output tokens, which is why its cost per finished task lands well below its sticker price.
Anthropic • Claude 4.5
$1.00 / $5.00
/ 1M tokens (input / output)
The fastest model Anthropic ships, still on the Claude 4.5 generation with a 200K window and an early-2025 knowledge cutoff. Worth it when response latency is the product requirement; otherwise Sonnet 5 offers more capability and five times the context for twice the price.
Input price
Claude Haiku 4.5 is 75% cheaper than GPT-5.6 Sol on input tokens.
Output price
Claude Haiku 4.5 is 75% cheaper than GPT-5.6 Sol on output tokens — usually the side that dominates the bill.
Monthly cost at three workload sizes
Standard (non-batch, non-cached) rates. Reasoning models will exceed these figures because thinking tokens bill as output.
| Workload | GPT-5.6 Sol | Claude Haiku 4.5 | Difference |
|---|---|---|---|
| Light — 1M in / 200K out | $8 | $2 | $6 |
| Moderate — 10M in / 2M out | $80 | $20 | $60 |
| Heavy — 100M in / 20M out | $800 | $200 | $600 |
Specification comparison
| Attribute | GPT-5.6 Sol | Claude Haiku 4.5 |
|---|---|---|
| Input (/ 1M tokens) | $4.00 | $1.00 |
| Output (/ 1M tokens) | $20.00 | $5.00 |
| Cached input | $0.40 | $0.10 |
| Context window | 1,048,576 tokens | 200,000 tokens |
| Max output | 128,000 tokens | 64,000 tokens |
| Native reasoning | Yes | Yes |
| Knowledge cutoff | 2026-02 | 2025-02 |
| Relative latency | high | low |
| Open weights | No | No |
| API model ID | gpt-5.6-sol | claude-haiku-4-5 |
| Status | stable | stable |
GPT-5.6 Sol: Promotional pricing (down from $5/$30) held at least through 2026-11-21. Prompts above 272K input tokens bill at higher rates; 'fast' processing is 2x.
Choose GPT-5.6 Sol if…
- Long-running autonomous coding agents
- Large-scale refactors and migrations
- Agentic browsing and computer use
- Scientific and financial analysis
Choose Claude Haiku 4.5 if…
- Real-time chat suggestions
- Lightweight extraction and tagging
- Guardrail and routing calls
- High-frequency background jobs
Frequently asked
Is GPT-5.6 Sol or Claude Haiku 4.5 cheaper?
Claude Haiku 4.5 is cheaper. On a blended 3:1 input-to-output workload it costs about 4.0x less than GPT-5.6 Sol.
Which has the larger context window, GPT-5.6 Sol or Claude Haiku 4.5?
GPT-5.6 Sol has the larger window at 1.05M tokens versus 200K.
Should I use GPT-5.6 Sol or Claude Haiku 4.5?
Pick GPT-5.6 Sol for frontier coding and long-horizon agents. Pick Claude Haiku 4.5 for lowest-latency claude responses. If cost dominates the decision, Claude Haiku 4.5 wins; if you need the capability ceiling, benchmark both on your own evals before committing.