Net Coin Days

Coin Days Created minus Coin Days Destroyed — positive means the network is aging (accumulating), negative means old coins are moving

Property	Value
Category	Coin Days
Unit	coin-days
Resolution	1d
Assets	BTC
Tier	Basic
API Endpoint	GET /v1/coindays
Field	net_coindays

Overview

Net Coin Days measures the daily balance between coin-days being created (by coins aging) and coin-days being destroyed (by coins being spent). It answers a simple but powerful question: is the Bitcoin network accumulating dormancy faster than it is spending it?

Since Coin Days Created equals the circulating supply (each BTC creates 1 coin-day per calendar day), Net Coin Days is simply the circulating supply minus Coin Days Destroyed.

Formula

$$\text{Net Coin Days}_t = \text{CDC}_t - \text{CDD}_t = S_t - \text{CDD}_t$$

Where:

• $S_t$ is the circulating supply on day $t$ (= Coin Days Created, since each BTC generates 1 coin-day per calendar day)
• $\text{CDD}_t$ is the total coin-days destroyed on day $t$

Interpretation

• Positive Net Coin Days (the common case): More coin-days are being created than destroyed — the network is net-accumulating dormancy, coins are aging
• Negative Net Coin Days (rare, extreme events): More coin-days were destroyed than created — an extraordinary amount of old coins moved. This is exceptionally rare and signals major market events
• Net approaching zero: A large share of the network's daily coin-day budget is being consumed by spending — high activity relative to supply
• Trend analysis: A sustained decline in Net Coin Days (even while still positive) indicates increasing spending of aged coins, often seen during distribution phases of bull markets

Use Cases

• Accumulation vs distribution regime detection: Persistently high Net Coin Days indicates strong HODLing behavior; declining Net suggests distribution
• Extreme event detection: Negative Net Coin Days days are so rare they serve as high-signal alerts for major market dislocations
• Normalized activity measure: By framing CDD relative to what the network produces in coin-days, Net provides context that raw CDD lacks
• Foundation for Coin Days Accumulated: Net Coin Days is the daily increment that feeds into the cumulative Coin Days Accumulated metric

API Usage

curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://api.blocklens.co/v1/coindays?start_date=2024-01-01&end_date=2024-12-31&limit=365"

Related Metrics

• Coin Days Destroyed — Sum of coin age × amount for all spent UTXOs per day — a fundamental measure of on-chain economic activity
• Coin Days Accumulated — Running total of all coin-days ever created minus all coin-days ever destroyed — the total stored economic energy in the network
• Circulating Supply — Total BTC ever mined