Send 20 to 40 cold emails per day per inbox, and plan around 30. That is the honest answer to how many cold emails per day per inbox is safe in 2026. The number does not come from a platform cap: Google Workspace technically lets one account send 2,000 messages a day. It comes from the spam complaint math. Since February 2024, Google and Yahoo cut off senders whose complaint rate reaches 0.3 percent, which is one angry recipient per 333 delivered emails. Cold email lives or dies on staying under that line, and small per-inbox volume is how you keep one bad day from becoming a burned domain.
If you search this question you will find answers of 25, 30 to 50, and 100 to 150 a day, often published weeks apart, and almost never with reasoning attached. The pattern behind the spread is simple: the vendors selling you inboxes and warmup seats quote the high numbers, and the people who fix burned domains quote the low ones. This guide referees. It walks through what the Google and Yahoo bulk sender rules actually say, what Microsoft's 2025 mirror of those rules did to Outlook delivery, the arithmetic for how many domains and inboxes you need to send 500 cold emails a day, and whether warmup tools still earn their subscription. Every number below is sourced from the platform rules or from named practitioner guides, so when the advice changes again, you will be able to re-derive the answer yourself.