GPT-5.5 Pro vs GPT-5.6 Sol
GPT-5.6 Sol and GPT-5.5 Pro are both premium OpenAI routes, but they answer different buyer questions after the July 2026 GPT-5.6 launch. Sol is the new GA frontier GPT-5.6 tier with refreshed launch-table evidence. GPT-5.5 Pro remains the older high-cost Pro route teams may still be running for premium reasoning or long-context workloads.
Pick GPT-5.6 Sol when you want OpenAI's newest GA frontier tier and July 2026 launch evidence for coding, agents, and multimodal work. Keep GPT-5.5 Pro only when your production harness, negotiated pricing, or verified Pro-specific behavior still outperforms Sol in acceptance tests. Frame this as a cost-and-tier decision rather than an unsupported benchmark sweep; do not invent GPT-5.5 Pro rows where the GPT-5.6 launch table only reports GPT-5.5 baseline.
Decision scorecard
Local evidence first| Signal | GPT-5.5 Pro | GPT-5.6 Sol |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1.05m | 1.05m |
| Cheapest output | $180/1M tokens | $30/1M tokens |
| Provider routes | 3 tracked | 2 tracked |
| Shared benchmarks | 5 shared | SWE-bench Pro leader |
Decision tradeoffs
- GPT-5.5 Pro has broader tracked provider coverage for fallback and procurement flexibility.
- GPT-5.5 Pro uniquely exposes Structured outputs in local model data.
- Local decision data tags GPT-5.5 Pro for Coding, RAG, and Agents.
- GPT-5.6 Sol holds a shared-benchmark lead on SWE-bench Pro, ahead by 6.0 points.
- GPT-5.6 Sol has the lower cheapest tracked output price at $30/1M tokens.
- Local decision data tags GPT-5.6 Sol for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
GPT-5.5 Pro
$69,000
Cheapest tracked route/tier: OpenAI API <=272K tokens (standard)
GPT-5.6 Sol
$11,500
Cheapest tracked route/tier: OpenAI API 0-272K input tokens
Estimated monthly gap: $57,500. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenAI API and OpenRouter; start route-level A/B tests there.
- GPT-5.6 Sol is $150/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Structured outputs before moving production traffic.
- Provider overlap exists on OpenAI API and OpenRouter; start route-level A/B tests there.
- GPT-5.5 Pro is $150/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- GPT-5.5 Pro adds Structured outputs in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-23 | 2026-07-09 |
| Context window | 1.05m | 1.05m |
| Parameters | — | — |
| Architecture | Decoder Only | Decoder Only |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Weights | Not released | Not released |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2025-12 | - |
Pricing and availability
| Pricing attribute | GPT-5.5 Pro | GPT-5.6 Sol |
|---|---|---|
| Input price | $30/1M tokens |
|
| Output price | $180/1M tokens |
|
| Providers |
Capabilities
| Capability | GPT-5.5 Pro | GPT-5.6 Sol |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | No |
| Code execution | Yes | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | GPT-5.5 Pro | GPT-5.6 Sol |
|---|---|---|
| SWE-bench Pro | 58.6 | 64.6 |
| Google-Proof Q&A | 93.6 | 94.6 |
| Terminal-Bench 2.1 | 78.2 | 88.8 |
| GeneBench-Pro | 20.5 | 31.5 |
| Artificial Analysis Intelligence Index | 55.0 | 58.9 |
Deep dive
This pair is about OpenAI tier selection after GPT-5.6 GA, not a generic family comparison. Sol is the new flagship GPT-5.6 route; GPT-5.5 Pro is a distinct premium SKU that should keep its own pricing and benchmark context.
Compare long-context economics explicitly. Both families use surcharges above roughly 272K input tokens in the tracked OpenAI pricing table, so million-token workloads need real prompt-length estimates rather than headline short-context rates.
Use Sol when stakeholder reviews need July 2026 GA launch rows and a clear successor narrative. Keep GPT-5.5 Pro when you still have verified Pro-route quality advantages in your own harness and migration would be mostly cost with no measured gain.
Do not recommend replacing every GPT-5.5 Pro deployment without task-specific evidence. Route-level A/B tests on coding agents, tool loops, and long-context retrieval packs are the safe migration path.
FAQ
Does GPT-5.6 Sol replace GPT-5.5 Pro?
Not by default. Sol is the new GA frontier GPT-5.6 tier, while GPT-5.5 Pro is a separate premium route. Compare them with your own acceptance tests and current OpenAI pricing rather than assuming Sol supersedes every Pro workload.
Which model is cheaper for long-context workloads?
Use the OpenAI pricing table for the exact prompt length. Both Sol and GPT-5.5 Pro can hit long-context surcharges above roughly 272K input tokens, so estimate full-request token counts before choosing on headline short-context prices alone.
Are GPT-5.5 Pro benchmarks directly comparable to GPT-5.6 Sol?
Only where the seed has comparable harness labels. Do not invent GPT-5.5 Pro rows from GPT-5.6 launch tables that report GPT-5.5 baseline instead of Pro.
Should every GPT-5.5 Pro deployment move to GPT-5.6 Sol?
No. Run route-level acceptance tests first. Keep GPT-5.5 Pro when verified Pro-route quality or negotiated pricing still wins; move to Sol when July 2026 GA launch evidence and standard-tier economics justify revalidation.
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Last reviewed: 2026-07-09. Data sourced from public model cards and provider documentation.