ChatGPT reached an estimated 100 million monthly users in two months.

ChatGPT reached an estimated 100 million monthly active users within two months of its launch, a figure that was widely reported as the fastest adoption of any consumer application at the time, but a fact-check by Lenz on Sep 7, 2026, rates the claim 'Mostly False' because Meta's Threads later reached 100 million registered users in five days, and the 100 million figure for ChatGPT was a third-party estimate, not an official OpenAI count.

ChatGPT reached an estimated 100 million monthly users in two months. The Claim ChatGPT's growth to 100 million monthly users within two months was the fastest adoption of any consumer application in history. NOT BS TOTAL BS MOSTLY BS — Verdict: Mostly False Verified by Lenz · Sep 7, 2026 The Short Version ChatGPT did reach an estimated 100 million monthly active users roughly two months after launch and was considered the fastest-growing consumer application at that time. The enduring historical superlative is outdated because Threads later reached 100 million registered users in five days. Those measurements are not perfectly equivalent, but the claim supplies no qualification preserving ChatGPT’s former record. Caveats The 100 million figure was a third-party estimate, not a confirmed OpenAI user count. ChatGPT held the widely reported adoption record in January 2023, not indefinitely. Comparisons with Threads mix monthly active users with registered-user or signup counts.