Flash or Pro? A rule that saves time and money.
Two models, one easy heuristic. Pick wrong and you either overpay or under-think the problem. Here is how to choose in five seconds.
Default to Flash. Switch to Pro only when the task has real multi-step reasoning and the cost of a wrong answer is high. Most work is a Flash job; Pro is for the hard 10%.
01V4 Flash — the workhorse
Fast, extremely cheap, and strong enough for the large majority of tasks: drafting, summarizing, everyday coding, classification, and high-volume jobs where price per call matters. When in doubt, start here.
02V4 Pro — for the hard 10%
Slower and pricier, but it reasons more deeply: tricky math and logic, gnarly debugging, multi-constraint planning, and analysis where being right matters more than being fast. If Flash gives a shaky answer on a hard problem, escalate to Pro.
03The shared superpower: ~1M tokens
Both models share a very large context window — roughly a million tokens — so the choice is about depth of reasoning, not how much they can read. Either one can ingest an entire report or codebase; Pro just thinks harder about it.