Claude Sonnet 5.5 vs Gemini 3.7 Flash
Anthropic · US | Google · US · Updated June 2026
Quick verdict
Pick Claude Sonnet 5.5 for terminal-bench 4.0 agentic coding jumps to 70.6%, up from claude sonnet 5's 10.3% or same $2/$10 per million token pricing as sonnet 5, with cache-read price cut 50% to $0.10/mtok as of october 7, 2026. Pick Gemini 3.7 Flash for strong intelligence-per-dollar - artificial analysis intelligence index 56 at introductory $0.75/$3.75 pricing or 1m-token context with full multimodal input (text, image, audio, video). On a tight budget at scale, Gemini 3.7 Flash is the value pick.
Claude Sonnet 5.5 (Anthropic) and Gemini 3.7 Flash (Google) are two of the models people most often weigh against each other in 2026. Claude Sonnet 5.5 is anthropic's September 28, 2026 mid-tier update — same $2/$10 pricing as Sonnet 5 but a large agentic-coding jump (Terminal-Bench 4.0: 70.6% vs 10.3%). Gemini 3.7 Flash is google's cheap, fast coding-and-agents workhorse - AA Index 56, a 1M context, and aggressive introductory pricing that beats GPT-5.6 Terra on value and speed. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences at a glance
- ▸Price: Gemini 3.7 Flash is about 2.7× cheaper on input ($0.75/$3.75 per 1M tokens vs $2/$10 per 1M tokens) — meaningful once you are processing millions of tokens a month.
- ▸Context window: 1M tokens vs 1M — within a few percent of each other, so treat this as a tie and test on your own long inputs, since usable recall varies by model.
- ▸Recency: Claude Sonnet 5.5 is the newer model by about 46 days (released September 28, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
| Spec | Claude Sonnet 5.5 | Gemini 3.7 Flash |
|---|---|---|
| Provider | Anthropic (US) | Google (US) |
| Released | September 28, 2026 | August 13, 2026 |
| Context window | 1M tokens (~1,500 pages) | 1M (~1,573 pages) |
| Price (in/out) | $2/$10 per 1M tokens | $0.75/$3.75 per 1M tokens |
| Open weight? | No — API only | No — API only |
| Modalities | text, image, code | text, image, audio, video, code |
| SWE-Bench Verified | Not published | Not published |
| MRCR v2 @ 1M | Not published | Not published |
Who wins what
Terminal-Bench 4.0 agentic coding jumps to 70.6%, up from Claude Sonnet 5's 10.3%
Claude Sonnet 5.5
Gemini 3.7 Flash is comparatively weak here — trails GPT-5.6 Terra on the hardest repo-scale and terminal-agent coding
Same $2/$10 per million token pricing as Sonnet 5, with cache-read price cut 50% to $0.10/MTok as of October 7, 2026
Claude Sonnet 5.5
Gemini 3.7 Flash is comparatively weak here — introductory pricing ($0.75/$3.75) reverts to $1.50/$7.50 on Jan 1, 2027
Scores close to Opus 5.5 on several benchmarks (e.g. GDPval-AA v2.1 knowledge-work Elo) at a fraction of the cost
Claude Sonnet 5.5
Anthropic's September 28, 2026 mid-tier update — same $2/$10 pricing as Sonnet 5 but a large agentic-coding jump (Terminal-Bench 4.0: 70.6% vs 10.3%) — and it is the newer of the two.
Strong intelligence-per-dollar - Artificial Analysis Intelligence Index 56 at introductory $0.75/$3.75 pricing
Gemini 3.7 Flash
Claude Sonnet 5.5 is comparatively weak here — anthropic is explicit that Opus 5.5 'remains clearly stronger' on complex, open-ended work requiring sustained judgment
1M-token context with full multimodal input (text, image, audio, video)
Gemini 3.7 Flash
Claude Sonnet 5.5 is comparatively weak here — 1M-token context isn't uniformly available across every platform/plan, consistent with the rest of the 5.5 family
Built for coding and agents, with roughly 3x faster output than GPT-5.6 Terra
Gemini 3.7 Flash
Google's cheap, fast coding-and-agents workhorse - AA Index 56, a 1M context, and aggressive introductory pricing that beats GPT-5.6 Terra on value and speed — and it runs cheaper at $0.75/$3.75 per 1M tokens.
Lowest cost at scale
Gemini 3.7 Flash
At $0.75/$3.75 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Gemini 3.7 Flash
At $0.75/$3.75 per 1M tokens it undercuts Claude Sonnet 5.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Gemini 3.7 Flash
Larger 1M window fits more in one prompt.
Anyone whose priority is terminal-bench 4.0 agentic coding jumps to 70.6%, up from claude sonnet 5's 10.3%
→ Claude Sonnet 5.5
It is specifically built for that.
Anyone whose priority is strong intelligence-per-dollar - artificial analysis intelligence index 56 at introductory $0.75/$3.75 pricing
→ Gemini 3.7 Flash
That is its strongest area.
Claude Sonnet 5.5: where it fits
Anthropic's September 28, 2026 mid-tier update — same $2/$10 pricing as Sonnet 5 but a large agentic-coding jump (Terminal-Bench 4.0: 70.6% vs 10.3%). Released September 28, 2026 by Anthropic, it is built for terminal-Bench 4.0 agentic coding jumps to 70.6%, up from Claude Sonnet 5's 10.3%, same $2/$10 per million token pricing as Sonnet 5, with cache-read price cut 50% to $0.10/MTok as of October 7, 2026, scores close to Opus 5.5 on several benchmarks (e.g. GDPval-AA v2.1 knowledge-work Elo) at a fraction of the cost, and anthropic highlights stronger document/slide generation, spreadsheet work, and visual chart recognition (Chartography: 61.6%).
Its trade-offs are real: anthropic is explicit that Opus 5.5 'remains clearly stronger' on complex, open-ended work requiring sustained judgment, 1M-token context isn't uniformly available across every platform/plan, consistent with the rest of the 5.5 family, and mid-tier update released a week after Opus 5.5 (Sept 22) — Haiku 5.5 followed Oct 7 to complete the family. At $2 in / $10 out per million tokens, it sits in the mid price band.
Gemini 3.7 Flash: where it fits
Google's cheap, fast coding-and-agents workhorse - AA Index 56, a 1M context, and aggressive introductory pricing that beats GPT-5.6 Terra on value and speed. Released August 13, 2026 by Google, it is built for strong intelligence-per-dollar - Artificial Analysis Intelligence Index 56 at introductory $0.75/$3.75 pricing, 1M-token context with full multimodal input (text, image, audio, video), built for coding and agents, with roughly 3x faster output than GPT-5.6 Terra, and wins broad-coding and web-development benchmarks against GPT-5.6 Terra.
Its trade-offs: introductory pricing ($0.75/$3.75) reverts to $1.50/$7.50 on Jan 1, 2027, trails GPT-5.6 Terra on the hardest repo-scale and terminal-agent coding, a fast 'workhorse,' not Google's top-intelligence model (Gemini 3.1 Pro is still the flagship), and some benchmark gains are Google's own figures. At $0.75 in / $3.75 out per million tokens, it sits in the budget price band.
The bottom line for this matchup
Claude Sonnet 5.5 and Gemini 3.7 Flash overlap enough that the right pick depends on your specific job. Gemini 3.7 Flash costs less per token; Gemini 3.7 Flash holds the larger context; and each leads in its own area — Claude Sonnet 5.5 for terminal-bench 4.0 agentic coding jumps to 70.6%, up from claude sonnet 5's 10.3%, Gemini 3.7 Flash for strong intelligence-per-dollar - artificial analysis intelligence index 56 at introductory $0.75/$3.75 pricing. Rather than crowning one, run the same hard task through both once and let the results decide.
Want both Claude Sonnet 5.5 and Gemini 3.7 Flash 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.
See pricingFrequently asked questions
Is Claude Sonnet 5.5 or Gemini 3.7 Flash 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 Sonnet 5.5 leans toward terminal-bench 4.0 agentic coding jumps to 70.6%, up from claude sonnet 5's 10.3% while Gemini 3.7 Flash leans toward strong intelligence-per-dollar - artificial analysis intelligence index 56 at introductory $0.75/$3.75 pricing, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Sonnet 5.5 or Gemini 3.7 Flash?
Gemini 3.7 Flash is cheaper — $2/$10 per 1M tokens vs $0.75/$3.75 per 1M tokens, roughly 2.7× apart on input.
Which has the bigger context window?
Effectively neither — 1M tokens vs 1M is a difference of a few percent. Remember advertised ≠ usable: recall typically degrades before the ceiling.
Can I use both Claude Sonnet 5.5 and Gemini 3.7 Flash together?
Yes — a multi-model platform like LumiChats gives you Claude Sonnet 5.5, Gemini 3.7 Flash 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 Sonnet 5.5 or Gemini 3.7 Flash?
Claude Sonnet 5.5 — released September 28, 2026, about 46 days after Gemini 3.7 Flash.
Related comparisons
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.