Earliest Timestamps

A ranked list of the 100 blocks whose timestamp goes furthest back relative to the previous block.

Bitcoin block timestamps do not need to be strictly increasing. A block is valid as long as its timestamp exceeds the Median Time Past (MTP) — the median of the timestamps of the 11 blocks immediately before it — and does not exceed network-adjusted time + 2 hours. Because a block only needs to beat the median of the previous 11, it can legitimately carry a timestamp earlier than its direct predecessor. The "Before prev." column shows by how many seconds the timestamp went back.

The largest rollbacks observed approach ~2 hours (≈ 7,200 seconds). This is not a coincidence: the 2-hour future limit is the widest the validation window can ever be, so two consecutive blocks that both push their timestamps to opposite extremes of that window — one to the maximum allowed future, the next to just above the MTP floor — can produce a rollback close to 2 hours. In practice a rollback of that size is extremely rare and requires a specific alignment of the previous 11 blocks' timestamps.

The top 100 entries are dominated by blocks from Bitcoin's first decade (2009–2015), when timestamp discipline was looser, clock synchronisation across miners was less reliable, and the smaller network meant individual miners had more influence over consecutive timestamps. Today a miner who deliberately backdates a block risks having it rejected if the timestamp falls below the MTP floor, which advances with every new block — making aggressive backdating increasingly risky. On a modern network, no rational miner would sacrifice a valid block reward for a marginal timestamp advantage. Sources: BIP 113 — Median Time-Past, Bitcoin Wiki — Block timestamp.