---
title: "Most of the mempool is not competing with you · Bitsaga Insights"
description: "What is actually inside the Bitcoin mempool, measured on 800 blocks and 6.3 million spent coins from a local archival node, and why a stuck transaction is usually queued behind dust it is not competing with."
url: "https://bitsaga.be/insights/what-is-in-the-mempool"
language: "en"
---

> What is actually inside the Bitcoin mempool, measured on 800 blocks and 6.3 million spent coins from a local archival node, and why a stuck transaction is usually queued behind dust it is not competing with.
[Insights](https://bitsaga.be/insights) · Mempool

# Most of the mempool is not competing with you

By [Rob Segers](https://bitsaga.be/about) · September 2, 2026

![Coins under a day old are 78.9% of confirmed blocks but 4% of the pending mempool, while coins over a year old are 2.8% of blocks and 41.6% of the mempool](https://bitsaga.be/images/insights/what-is-in-the-mempool.png)

Almost everyone who opens a block explorer is asking one thing: **when will my transaction confirm?** The usual answer is a fee rate and a place in a queue. Measuring what that queue is actually made of gives a better answer, and a more reassuring one.

## Blocks and the mempool are opposites

Across 800 consecutive blocks, holding 3.8 million transactions and 6.3 million spent coins, confirmed Bitcoin is overwhelmingly fresh:

| Age of the coin when spent | Share of inputs in blocks |
|---|---|
| Under 1 hour | 50.8% |
| Under 1 day | 78.9% |
| Over 1 year | 2.8% |

Sample the pending mempool at the same moment and it inverts: barely 4% of pending inputs are under a day old. Transactions paying competitive fees pass through too quickly to be caught in a snapshot. What piles up is what nobody is in a hurry to mine.

The mempool is not a preview of the next block. It is the residue of everything that did not make it into the last ones.

## Two percent of transactions, a third of the queue

In a sample of 1,200 pending transactions, those spending a coin older than a year were just **2% of the transactions** but carried **28.8% of all the inputs**. Two of them had a thousand inputs each. They paid a median of **0.20 sat/vB**, the lowest fees in the pool: dust consolidations, sweeping up hundreds of tiny old outputs, deliberately paying as little as possible and content to wait days.

So a large part of what looks like a queue ahead of you is not competing with you at all. Only the backlog at or above *your own* fee rate decides when you get mined, and that number is usually far smaller than the headline mempool size.

Live tool

How much transaction fee to set

A probability with the certainty stated, or a deadline turned into the fee that meets it. Shows the next blocks, the fee range each will contain, and which one a given fee falls into.

Open the estimator →

[Read more](https://bitsaga.be/fee-estimator/)

## Why nobody publishes their accuracy

There is a structural reason, and it is not modesty. **The blockchain never records when a transaction entered the mempool.** It records the block it landed in and nothing about the wait before it. That exists only inside each node, only while the transaction is pending, and it is discarded the moment it confirms. A confirmation-time model therefore cannot be tested against history, and no archive can be reconstructed. The only way to get the data is to record it continuously and wait.

That recording is now running here, and the accuracy of these predictions will be published once there is enough of it to mean anything, including where they are wrong.

Measured with one unauthenticated call per block to a local Bitcoin Core node with `txindex` enabled. No third-party API, no chain-analysis service.