DataLLM LabGPT-5 vs Gemini 3: Which Should You Use?
GPT-5 and Gemini 3 are the OpenAI and Google flagships of 2026, and the choice usually comes down to one trade-off: GPT-5 edges ahead on agentic and coding tasks, while Gemini 3 is materially cheaper and stronger on long-context multimodal work. This guide puts both on independent benchmarks, shows the real price gap, and gives a clear pick by job — coding, agents, multimodal, and cost-sensitive scale.
The short answer
GPT-5 for hard agentic and coding work; Gemini 3 for cheap, long-context, multimodal work. GPT-5 leads independent coding and terminal benchmarks; Gemini 3 trails by a few points but costs a half to a third as much and is the stronger multimodal/long-context family. For most cost-sensitive workloads Gemini wins on value; for the hardest agentic tasks GPT-5 earns its premium.
| GPT-5 (OpenAI) | Gemini 3 (Google) | |
|---|---|---|
| Flagship | GPT-5.5 / GPT-5.4 | Gemini 3.1 Pro / 3.5 Flash |
| SWE-bench Verified | 82.6% (5.5) | 78.8% (3.5 Flash) |
| Price (flagship out) | $30 (5.5) / $15 (5.4) | $12 (Pro) / $9 (Flash) |
| Strength | Agentic, terminal, coding | Multimodal, long-context, value |
Specs & price
| Model | Input | Output | Context |
|---|---|---|---|
| GPT-5.5 | $5 | $30 | ~1M |
| GPT-5.4 | $2.50 | $15 | 1.1M |
| Gemini 3.1 Pro | $2 | $12 | 1M |
| Gemini 3.5 Flash | $1.50 | $9 | 1M |
Per 1M tokens, USD, June 2026.
The price gap
The clearest practical difference is cost. On output — the expensive side — Gemini undercuts GPT-5 across the board:
Benchmarks
On the independent SWE-bench Verified board, GPT-5.5 (82.6%) leads Gemini 3.5 Flash (78.8%) — a real but single-digit gap. GPT-5 also tends to lead agentic terminal benchmarks. The honest read: GPT-5 is a few points better on coding and agentic execution, not categorically ahead. Whether those points are worth 2–3× the price is the whole decision.
Where GPT-5 wins
- Agentic coding & terminal execution — leads the benchmarks; the GPT-5 Codex variants are tuned for coding agents.
- Peak reasoning — GPT-5.5 and the Pro tier for the hardest multi-step problems.
- Ecosystem — the widest tooling and integration support, being the native OpenAI format.
Where Gemini 3 wins
- Cost — a half to a third of GPT-5's output price; the value pick at scale.
- Multimodal — natively handles image, audio, video, and PDF input.
- Long context — strong, cheap 1M-token processing for document and media pipelines.
- A usable free tier — via Google AI Studio, unlike OpenAI's paid-only API.
Which to pick
Pick GPT-5
- Hard agentic coding, terminal automation, peak reasoning, deep OpenAI tooling.
Pick Gemini 3
- Cost-sensitive scale, multimodal pipelines, long-context document work, prototyping on the free tier.
Best move Use both
- Route Gemini for cheap/multimodal, GPT-5 for hard agentic — one key, per-request choice.
Also consider The full field
- Claude leads independent coding overall; DeepSeek is cheaper still. See best LLM API.
Run GPT-5 and Gemini 3 side by side
GPT-5.4, Gemini 3.1 Pro/Flash, Claude Opus 4.7 and 300+ more — one OpenAI-compatible key, live price comparison, route per request.
FAQ
Is GPT-5 better than Gemini 3?
On independent SWE-bench Verified, GPT-5.5 (82.6%) edges Gemini 3.5 Flash (78.8%), and GPT-5 leads agentic/terminal tasks. Gemini 3 is competitive on coding, much cheaper, and stronger on multimodal/long-context. It depends on the workload.
Is Gemini cheaper than GPT-5?
Yes — Gemini 3.1 Pro $2/$12, 3.5 Flash $1.50/$9 versus GPT-5.5 $5/$30 and GPT-5.4 $2.50/$15. Typically a half to a third of GPT-5's output price.
Which is better for coding?
GPT-5 has the edge on coding benchmarks and agentic execution (Codex variants). Gemini 3 codes well and is cheaper — a strong value pick for high-volume coding.
Which is better for long context and multimodal?
Gemini 3 — both offer ~1M context, but Gemini is natively multimodal and priced low for long-context work.
GPT-5 or Gemini 3 for agents?
GPT-5 (5.5 / Codex) tends to lead agentic terminal/tool-use. Gemini 3 is capable and cheaper for agent fleets where cost-per-task matters. Test both.
Can I use both with one API?
Yes — via an OpenAI-compatible gateway like DataLLM Lab you reach GPT-5.4 and Gemini 3.1 Pro (and 300+ others) with one key and route by task.