Head to head
Claude Sonnet 5 vs Claude Sonnet 4.5
Claude Sonnet 5 from Anthropic against Claude Sonnet 4.5 from Anthropic — specification, price and every benchmark both makers have published, in one table.
Benchmarks
No shared benchmarks
These two models have no benchmark in common with published figures for both, so there is nothing to compare directly. The specification and price rows below are still like for like.
Price
Claude Sonnet 5 is cheaper
On a 3:1 input-to-output mix, Claude Sonnet 5 costs $4.00 per million tokens against $6.00 for Claude Sonnet 4.5 — about 1.5× less. Remember that a reasoning model bills its thinking as output, so cost per answer can diverge much further than cost per token.
What actually differs
- These two are closely matched on the specification side — same broad capabilities, same licensing posture. The decision comes down to the benchmark rows and the price.
Scorecard
Which is better at what
Maths, coding, reasoning and the rest — one line each, averaged over the benchmarks both models actually report.
Claude Sonnet 5 has no published benchmark scores
Its maker has not released figures for any of the evaluations tracked here, so there is nothing to put in a score column. Rather than estimate, infer from a sibling model, or quote the base model's numbers as if they were its own, this page leaves those rows empty and compares what genuinely can be compared: parameters, context window, modalities, licence and cost.
The moment those figures are published they go in — send them with a link to the source.
| Category | Claude Sonnet 5 | Claude Sonnet 4.5 | Better at this |
|---|---|---|---|
| ReasoningOnly one model reports this | — | — | Not comparable |
| MathsOnly one model reports this | — | — | Not comparable |
| CodingOnly one model reports this | — | — | Not comparable |
| KnowledgeNeither model reports this | — | — | Not comparable |
| MultimodalOnly one model reports this | — | — | Not comparable |
| Instruction followingNeither model reports this | — | — | Not comparable |
| Human preferenceNeither model reports this | — | — | Not comparable |
| Categories won | No category has a test both models report | ||
Each category averages only the benchmarks every model here reports, so no one is credited for a test the other did not run. A category with no shared test is marked Not comparable rather than guessed at.
Side by side
Claude Sonnet 5 and Claude Sonnet 4.5, row by row
| Attribute | Claude Sonnet 5Anthropic | Claude Sonnet 4.5Anthropic |
|---|---|---|
| Specification | ||
| MakerWho built it | Anthropic | Anthropic |
| Released | 2026-06 | 2025-09 |
| Context windowHow much can go in at once | 1,000,000 tokens | 1,000,000 tokens |
| Max output | 128,000 tokens | 64,000 tokens |
| Input | Text, Image | Text, Image |
| ReasoningSpends extra tokens thinking before it answers | Yes | Yes |
| Tool calling | Yes | Yes |
| Knowledge cutoff | 2026-01 | 2025-01 |
| Licence | Proprietary | Proprietary |
| Open weightsCan you download and run it yourself | No | No |
| Price | ||
| Input priceUSD per million tokens in | $2.00 | $3.00 |
| Output priceUSD per million tokens out | $10.00 | $15.00 |
| Cached input | $0.20 | $0.30 |
| Blended 3:1A 3-in-to-1-out million-token mix — a fairer single number than input price alone | $4.00Cheapest | $6.00 |
| Published benchmarks | ||
| GPQA Diamond198 graduate-level physics, chemistry and biology questions written to be Google-proof. PhD holders in the matching field score about 65%. | Not reported | |
| AIME 2025The American Invitational Mathematics Examination — 15 problems, integer answers, no partial credit. A standard test of multi-step maths reasoning. | Not reported | |
| SWE-bench Verified500 human-validated GitHub issues from real Python repositories. The model must produce a patch that makes the project's own tests pass. | Not reported | |
| MMMUCollege-level questions that require reading charts, diagrams, tables and photographs alongside the text. | Not reported | |
| Links | Full page | Full page |
| Row verified | 2026-09 | 2026-08 |
Where these numbers come from
Every score on this page is a published figure, taken from the model's own card, system card, technical report or release post, or from a public leaderboard. CorX Labs did not run these evaluations. Most are self-reported by the lab that built the model, which means they were produced under that lab's own choice of prompt, scaffold and number of attempts — so treat them as a starting point for a shortlist, not as a settled ranking.
A score someone other than the model's maker measured is marked Independent and names its measurer. Those are the stronger numbers on this page — an outside harness has no reason to flatter anyone — and there are not many of them.
Where a figure has not been published, the cell reads Not reported rather than an estimate. Nothing here is inferred, interpolated or guessed. Each model records the month its row was last checked. Full method and caveats.
Questions
Claude Sonnet 5 or Claude Sonnet 4.5?
Is Claude Sonnet 5 better than Claude Sonnet 4.5?
These two models have no benchmark in common with published figures for both, so there is nothing to compare directly. The specification and price rows below are still like for like.
Which is cheaper, Claude Sonnet 5 or Claude Sonnet 4.5?
On a 3:1 input-to-output mix, Claude Sonnet 5 costs $4.00 per million tokens against $6.00 for Claude Sonnet 4.5 — about 1.5× less. Remember that a reasoning model bills its thinking as output, so cost per answer can diverge much further than cost per token.
What is the difference between Claude Sonnet 5 and Claude Sonnet 4.5?
These two are closely matched on the specification side — same broad capabilities, same licensing posture. The decision comes down to the benchmark rows and the price.
