Coin Days Destroyed
Coin days destroyed (CDD) is an on-chain metric that multiplies the amount of coins spent by the number of days since those coins last moved. It shows whether coins changing hands are fresh or have been dormant for a long time.
How coin days are counted
Bitcoin records balances as unspent transaction outputs (UTXOs), and each UTXO carries the time it was created. While a UTXO sits untouched, it accumulates coin days: its amount in BTC multiplied by the days it has existed. When it is spent, all of those coin days are destroyed at once, and the output's new owner starts again from zero.
CDD for a block or a day is the sum of the coin days destroyed by every output spent in that period. The metric works on any UTXO-based chain, but it is mostly used for Bitcoin.
A worked example
Say on one day two transactions happen. In the first, 100 BTC that were received yesterday move again: 100 multiplied by 1 day equals 100 coin days destroyed. In the second, 10 BTC that sat untouched for 1,000 days move: 10 multiplied by 1,000 equals 10,000 coin days destroyed. The second transaction moved a tenth of the coins but contributes a hundred times the CDD. That is the point of the metric: it highlights long-held coins and largely ignores fast-turnover trading.
How analysts read it
A spike in CDD means a lot of old coins moved. Analysts often read this as long-term holders becoming active, for example taking profit during strong rallies, and pay closer attention when the spike coincides with coins flowing to exchanges. Persistently low CDD suggests long-term holders are mostly sitting still.
Because raw CDD grows as the supply grows, analysts use variants: supply-adjusted CDD divides by circulating supply, binary CDD only records whether a day was above or below its long-run average, and dormancy divides CDD by the number of coins moved to show the average age of each spent coin.
Limits and blind spots
Movement is not the same as selling. An exchange or custodian shuffling old coins into new wallets, a holder moving funds to a fresh hardware wallet, or a single entity consolidating outputs can all create large spikes without any market sale. CDD does not show the direction of trading, and one large transaction can dominate a day. It is best read together with exchange flows and other context, not as a signal on its own.
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Frequently asked questions
Does a high coin days destroyed reading mean holders are selling?
Not necessarily. It means old coins moved, which can be a sale, but also a custody change, wallet upgrade or internal exchange transfer.
Why is it called destroyed?
Coin days accumulate while a coin is unspent and reset to zero when it moves, so the accumulated days are said to be destroyed by the spend.
Can coin days destroyed be calculated for Ethereum?
Not in the same way. Ethereum uses account balances rather than UTXOs, so there is no clean age for each coin and analysts rely on approximations instead.
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