Model comparison
Claude Sonnet 5.5 vs Solar Pro4
Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 42.1 on the Noometry Index. Solar Pro4 costs 7.6× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.
Last verified . 13 shared benchmarks.
UpstageSummary
- They share 13 benchmarks with published results for both. Claude Sonnet 5.5 scores higher in 8 categories and Solar Pro4 in 0 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Sonnet 5.5 leads 87.9 to 38.8.
- Solar Pro4 is cheaper at $0.30 / $1.20 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.5.
- Claude Sonnet 5.5 accepts more context: 1M tokens versus 524K.
Side by side
| Claude Sonnet 5.5 | Solar Pro4 | |
|---|---|---|
| Provider | Anthropic | Upstage |
| Noometry Index | 61.9 | 42.1 |
| Released | 2026-09-28 | 2026-08-06 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 524K |
| Max output | 128K | 131K |
| Input $ / M tokens | $2 | $0.30 |
| Output $ / M tokens | $10 | $1.20 |
| Results tracked | 32 | 18 |
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Category by category
Coding Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 67.3 (#6), Solar Pro4: 40.1 (#149)
| Benchmark | Claude Sonnet 5.5 | Solar Pro4 |
|---|---|---|
| LMArena WebDev | 1774 | 1371 |
| LMArena Coding | 1513 | 1437 |
| FrontierCode | 52.1% | — |
| CursorBench | 55.5% | — |
| FrontierSWE | 61.9% | — |
| SciCode | 61% | — |
| ALE-Bench | 1,819 | — |
Agentic & Tool Use Not comparable
Claude Sonnet 5.5: 45.0 (#16), Solar Pro4: —
| Benchmark | Claude Sonnet 5.5 | Solar Pro4 |
|---|---|---|
| APEX-Agents | 75.5% | — |
Reasoning Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 54.0 (#28), Solar Pro4: 28.5 (#104)
| Benchmark | Claude Sonnet 5.5 | Solar Pro4 |
|---|---|---|
| LMArena Hard Prompts | 1495 | 1399 |
| NYT Connections (extended) | 80.5% | — |
| CritPt | 31.4% | — |
| Mystery Game Puzzles | 65% | — |
| Epoch Capabilities Index | 165.03 | — |
Math Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 87.9 (#6), Solar Pro4: 38.8 (#128)
| Benchmark | Claude Sonnet 5.5 | Solar Pro4 |
|---|---|---|
| LMArena Math | 1510 | 1416 |
| FrontierMath (Tiers 1-3) | 88.8% | — |
| FrontierMath Tier 4 | 80.5% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| ProofBench | 100% | — |
| FrontierMath Erdős | 2.9% | — |
Knowledge Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 66.0 (#12), Solar Pro4: 39.8 (#129)
| Benchmark | Claude Sonnet 5.5 | Solar Pro4 |
|---|---|---|
| LMArena Expert | 1540 | 1427 |
| GPQA Diamond | 95.6% | — |
| SimpleQA Verified | 46.5% | — |
Multimodal Not comparable
Claude Sonnet 5.5: 51.5 (#6), Solar Pro4: —
| Benchmark | Claude Sonnet 5.5 | Solar Pro4 |
|---|---|---|
| LMArena Vision | 1289 | — |
| Furniture Assembly | 75% | — |
Multilingual Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 55.3 (#30), Solar Pro4: 48.7 (#139)
| Benchmark | Claude Sonnet 5.5 | Solar Pro4 |
|---|---|---|
| LMArena Non-English | 1452 | 1361 |
| LMArena Chinese | 1522 | 1415 |
| LMArena Russian | 1451 | 1360 |
| LMArena French | — | 1397 |
| LMArena German | — | 1364 |
| LMArena Japanese | — | 1309 |
| LMArena Korean | — | 1382 |
| LMArena Spanish | — | 1401 |
Instruction Following Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 78.3 (#11), Solar Pro4: 72.7 (#132)
| Benchmark | Claude Sonnet 5.5 | Solar Pro4 |
|---|---|---|
| LMArena Instruction Following | 1495 | 1377 |
Long Context Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 45.9 (#28), Solar Pro4: 42.1 (#130)
| Benchmark | Claude Sonnet 5.5 | Solar Pro4 |
|---|---|---|
| LMArena Longer Query | 1498 | 1381 |
Writing & Preference Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 66.0 (#40), Solar Pro4: 56.5 (#138)
| Benchmark | Claude Sonnet 5.5 | Solar Pro4 |
|---|---|---|
| LMArena Text | 1471 | 1386 |
| LMArena Creative Writing | 1465 | 1316 |
| LMArena Multi-Turn | 1474 | 1385 |
Frequently asked questions
Is Claude Sonnet 5.5 better than Solar Pro4?
Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 42.1 on the Noometry Index. Solar Pro4 costs 7.6× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.
Which is cheaper, Claude Sonnet 5.5 or Solar Pro4?
Solar Pro4 is cheaper. It lists at $0.30 per million input tokens and $1.20 per million output tokens; Claude Sonnet 5.5 lists at $2 and $10.
Is Claude Sonnet 5.5 or Solar Pro4 better for coding?
Claude Sonnet 5.5 scores higher on coding benchmarks: 67.3 versus 40.1 in the Noometry coding category.
Which has the bigger context window?
Claude Sonnet 5.5 does, with 1M tokens against 524K.
How many benchmarks do Claude Sonnet 5.5 and Solar Pro4 share?
13 benchmarks have published results for both models. Claude Sonnet 5.5 has 32 scored results on Noometry and Solar Pro4 has 18.