Capability · Comparison
Gemini 1.5 Pro vs GPT-4o
Gemini 1.5 Pro (Google, Feb 2024) and GPT-4o (OpenAI, May 2024) were the two big flagships of 2024. Gemini 1.5 Pro set the long-context bar at 2M tokens and established native video understanding; GPT-4o defined multimodal chat with native audio. Both are now legacy — Gemini 2.5 Pro and GPT-5 are the current frontier.
Side-by-side
| Criterion | Gemini 1.5 Pro | GPT-4o |
|---|---|---|
| Release | February 2024 | May 2024 |
| Context window | 2,000,000 tokens | 128,000 tokens |
| Multimodal | Text + vision + audio + video (native video) | Text + vision + audio |
| MMLU | ≈85.9% | ≈88.7% |
| Needle-in-haystack at 1M+ | Strong (the 1.5 Pro headline) | N/A — 128k ceiling |
| Pricing ($/M input at EOL) | $1.25 (short) / $2.50 (>128k) | $5 |
| Status in 2026 | Legacy — superseded by Gemini 2.5 Pro | Legacy — superseded by GPT-5 |
| Ecosystem | Vertex AI, AI Studio | Azure OpenAI, Assistants, Batch, Realtime |
Verdict
Gemini 1.5 Pro was the long-context and video champion; GPT-4o was the reasoning and audio champion. For new builds, don't choose either. Migrate Gemini 1.5 Pro workloads to Gemini 2.5 Pro (better on every axis). Migrate GPT-4o workloads to GPT-4.1 (drop-in) or GPT-5 (real upgrade). If you specifically need 1M+ context in 2026, Gemini 2.5 Pro and Claude Opus 4.7 are the top picks.
When to choose each
Choose Gemini 1.5 Pro if…
- Only if you're pinned to Gemini 1.5 Pro for eval / compliance reasons.
- You need legacy 2M context and can't migrate yet.
- Otherwise: upgrade to Gemini 2.5 Pro.
Choose GPT-4o if…
- Only if you're pinned to GPT-4o for eval stability.
- You're on legacy Assistants API and haven't migrated to Responses.
- Otherwise: upgrade to GPT-4.1 or GPT-5.
Frequently asked questions
Is Gemini 1.5 Pro still worth using for long context?
Not vs current models. Gemini 2.5 Pro, Claude Opus 4.7, and GPT-5 all offer 1M-token windows with better quality than 1.5 Pro. Only stay on 1.5 Pro if pinned.
What replaced GPT-4o's native audio?
The Realtime API (still GPT-4o-based initially) and later GPT-5's audio stack. New voice products should target GPT-5 or GPT-Realtime.
Can I still get the 2M context of Gemini 1.5 Pro in a current model?
Gemini 2.5 Pro advertises a 2M-token window for some tiers. In practice most teams cap at 1M for cost and latency reasons.
Sources
- Google — Gemini 1.5 Pro — accessed 2026-04-20
- OpenAI — GPT-4o — accessed 2026-04-20