Coin Days Destroyed

Coin Days Destroyed (CDD) is an on-chain metric that weights the movement of coins by how long they sat unspent. Each coin accumulates one coin-day for every day it remains dormant in an unspent transaction output; when it is finally spent, those accumulated coin-days are "destroyed." The metric is calculated by multiplying the quantity of coins moved by the number of days each had been held, then summing across all transactions in a period. It is one of the oldest on-chain indicators — the idea dates back to Bitcoin's earliest analysts — and it endures because it asks a sharper question than raw volume: not how much moved, but whose coins moved.

Why dormancy is weighted

Plain transaction volume treats a coin that moved yesterday and a coin dormant for five years identically, so high-frequency churn — exchange shuffles, self-transfers, trading bots — dominates the signal. CDD does not. By giving older coins proportionally more weight, it emphasizes activity by long-dormant supply, generally associated with experienced, long-horizon holders, over the noise of recently moved coins. A coin held one year that moves destroys roughly 365 coin-days; the same coin moved after a day destroys just one. The arithmetic is possible because of Bitcoin's ledger design: every UTXO carries its creation time on-chain, so age at spend is a fact any full node can compute — no oracle, no exchange data, no trust.

How it is interpreted

A sharp spike in CDD signals that significant old supply has moved: long-held coins being sold, repositioned, or migrated. Sustained low CDD indicates that older holdings are staying put — historically the texture of accumulation phases, when conviction holders sit tight. Interpretation demands humility, though. A spike is a fact; its meaning is a guess. Old coins move for many reasons besides selling: custody migrations to new multisig setups, exchange cold-wallet reorganizations, inheritance handoffs, or a holder finally adopting a hardware wallet. Analysts therefore read CDD alongside destination heuristics and companion metrics — SOPR for whether moved coins realized profit or loss, HODL Waves for how the age distribution of supply is shifting.

Refinements

Two derivatives normalize the raw figure. Dormancy divides CDD by transaction volume, yielding the average age of each coin moved — high dormancy means the day's flow skewed old even if total volume was modest. Supply-adjusted CDD divides by circulating supply so readings can be compared across cycles: a million coin-days destroyed meant something different when far fewer coins existed. Binary variants flag simply whether a period's CDD ran unusually hot against its long-run average.

Framing

This entry is educational and not trading advice — CDD describes movement, not intent, and it predicts nothing by itself. Its quiet virtue is epistemic: because coin age is recorded in the ledger every node validates, this is holder behaviour you can audit from your own copy of the chain rather than take on a dashboard's word. Built from the age and value of spent outputs, CDD pairs naturally with the whole realized-value family, including realized cap.

A concrete example anchors the intuition: 50 BTC dormant since 2015 moving today destroys on the order of two hundred thousand coin-days — more than ten thousand coins churning through exchanges after a day's rest. One transaction, invisible in volume terms, dominates the day's CDD. That asymmetry is the entire point of the metric, and it is why analysts watch it around cycle turning points, when coins from Bitcoin's earliest years occasionally stir and briefly dominate the chart on their own. If you want to see it for yourself, most on-chain analytics platforms publish the series — and a full node holds everything needed to rebuild it independently.