What Mempool Heat measures
Mempool Heat is a composite index created by bitcoinnews.io that answers a simple question: how active is the Bitcoin network right now? It combines two real-time signals — network fee pressure and large-value transaction volume — into a single score on a 0–100 scale.
Unlike sentiment indicators that rely on surveys or social media, Mempool Heat is derived entirely from on-chain and mempool data. It reflects what is actually happening on the network at any given moment.
How it works
The score is a weighted average of two components:
- Fee component (60% weight) — The fastest recommended fee rate (in sat/vB) is transformed using a logarithmic scale. This means the score rises quickly at low fee levels but requires progressively larger fee spikes to push higher. A fee of 1 sat/vB produces a score around 15; 10 sat/vB reaches roughly 50; fees need to exceed 100 sat/vB to approach 100.
- Whale component (40% weight) — Each unconfirmed transaction in the mempool with a total output exceeding 10 BTC adds 20 points, capping at 100 (5 or more whale transactions). This captures large-value activity that fee rates alone may not reflect.
The final score is the rounded weighted sum: score = round(fee × 0.6 + whale × 0.4).
Reading the scale
| Range | Label | What it means |
|---|---|---|
| 0–24 | Cold | Low fees, few large transactions. Cheap to transact. |
| 25–49 | Warm | Moderate activity. Fees are reasonable but rising. |
| 50–74 | Hot | Significant fee pressure and/or whale activity. Consider timing transactions. |
| 75–100 | Blazing | Extreme congestion. High fees, heavy whale movement. Wait if possible. |
Data sources and update frequency
Fee data comes from the mempool.space recommended fees API. Whale transactions are unconfirmed mempool transactions with total output exceeding 10 BTC, sourced from the mempool.space recent transactions endpoint. Both inputs refresh on the server approximately every 8 seconds. The dashboard displays the latest value via WebSocket with a 1-second throttle.
Limitations
- The score reflects mempool state, not confirmed blocks. A sudden block confirmation can drop fees and whale count simultaneously, causing rapid score changes.
- Whale transactions are measured by total output value, which includes change outputs returned to the sender. A 50 BTC output does not necessarily mean 50 BTC changed hands.
- The logarithmic fee curve means the score is most sensitive in the 1–20 sat/vB range. During fee spikes above 100 sat/vB, the fee component is effectively saturated at 100.
- The 10 BTC whale threshold and component weights (60/40) are fixed parameters chosen by bitcoinnews.io. They are not derived from any external standard.
For the complete technical specification, see the methodology page.