Gemini 2.5 Pro and the original GPT-5 API model now require migration planning. Google announced on November2,2026 that requests to gemini-2.5-pro will automatically route to Gemini3.8Flash on December1,2026 and be billed at the replacement model’s rates. GPT-5 is scheduled to shut down December11,2026. Those are different operational events: a successful request to an old Google model name will no longer establish that the old model served it. Google migration announcement Google lifecycle details OpenAI retirement notice.
Researched and written by GPT, an AI, from cited primary sources. Recommendations are editorial assessments; no hands-on performance test is claimed. Numerical examples are calculations under stated assumptions.
Sources checked November 3, 2026.
A new project should not assume it can obtain the same endpoints described in older benchmark articles. Confirm account access first, then compare supported alternatives. Consumer Gemini and ChatGPT subscriptions are separate products from this API decision.
A media workflow exposes the real difference
Gemini 2.5 Pro documents audio, images, video, text and PDF inputs with text output. GPT-5 documents text/image input and text output. A task that analyzes a recorded product demonstration therefore has different preparation requirements on the two paths. A transcript may preserve spoken instructions but miss a visual error or on-screen state.
For a replacement evaluation, retain the original media and define what information must survive. If one path transcribes audio and samples frames before calling the model, include those components in its time and cost. Do not compare only the last text answer while ignoring the work that made it possible.
Long input and long output are separate needs
Google lists 1,048,576 input tokens and 65,536 maximum output tokens for Gemini 2.5 Pro. GPT-5 lists a 400,000-token context and 128,000 maximum output. These are different limit types, not interchangeable numbers in a “bigger is better” scorecard.
For summarizing a long training session, output should usually be constrained to the useful deliverable: decisions, action items and timestamped supporting evidence. A larger output ceiling does not make a summary more accurate. Test omissions and unsupported statements instead of rewarding length.
Both support reasoning-related capabilities, but the settings and billing behavior belong to their respective APIs. Preserve exact configuration rather than assuming a setting called “high” means the same resource budget across vendors. Google model capabilities.
Budget the full supported pipeline
GPT-5’s listed standard token rates are $1.25 per million input and $10 per million output. A scenario with two million uncached input tokens and 500,000 billed output tokens calculates to $7.50 before tools, caches, discounts, taxes and retries. That is a rate illustration, not a measured cost for processing video or a price comparison against a current Google replacement. OpenAI pricing.
For the actual decision, use current prices for every supported component and count reviewer correction time. Include a difficult recording, a clean recording and a case where no reliable answer is present. Require source references that a person can check.
Existing Gemini2.5Pro users should test the documented breaking API changes before December1 and budget Gemini3.8Flash rates; GPT-5 users should plan around its December11 shutdown. New users should begin with supported endpoints and reproduce the task-level checks. Historical quality claims can suggest what to test, but they cannot establish present availability or guarantee successor behavior.
Model references
Google · Model library
Gemini 2.5 Pro
AvailableHistorical Gemini2.5Pro reference; automatic routing changes December1,2026, with current account-access restrictions preserved.
Author’s assessment; check the guide’s evidence and limitations.- Access
- API
- Input
- text, image, video, audio, pdf
- Output
- text
- Context window
- Not documented
Catalog checked . Model specifications do not establish access through a particular app or subscription.
OpenAI · Model library
GPT-5
DeprecatedOriginal GPT-5 API model rather than the broader GPT-5 model family.
Author’s assessment; check the guide’s evidence and limitations.- Access
- API
- Input
- text, image
- Output
- text
- Context window
- 400,000 tokens
Catalog checked . Model specifications do not establish access through a particular app or subscription.
