Complete guide to reading Bitcoin block explorers using mempool.space. Covers transaction anatomy, confirmations, fee rates, mempool visualization, address lookup, block anatomy, RBF, CPFP, and privacy best practices.
A block explorer is a website that lets you browse the Bitcoin blockchain — every transaction, every block, every address, in real time. It's Bitcoin's public ledger made human-readable.
Think of it as Google for the Bitcoin network. Anyone can look up any transaction, verify any payment, track any address, and inspect any block — without permission from any authority.
The most popular and powerful Bitcoin block explorer in 2026 is mempool.space. This guide walks you through everything it shows you and how to use it to track transactions, understand fees, and verify your own payments.
To verify a payment was received: When someone sends you Bitcoin, you don't have to trust their word. Look up the transaction on a block explorer and see it yourself.
To track a pending transaction: Bitcoin transactions don't confirm instantly. The block explorer shows you exactly where your transaction is in the queue — and why it might be slow.
To understand fees: The mempool (the waiting room for unconfirmed transactions) is visible in real time. You can see exactly what fee rate is needed to get confirmed in the next block.
To prove a payment: If a payment is disputed, the block explorer provides an immutable, timestamped record that anyone can verify.
To research an address: Want to see the transaction history of a Bitcoin address? Block explorers show every inbound and outbound transaction, current balance, and total volume.
Navigate to mempool.space in your browser. You'll see a live dashboard of the Bitcoin network. Here's a map of everything on the homepage:
The most distinctive feature of mempool.space is the mempool visualization — the colored blocks showing pending transactions.
Each colored block represents a theoretical "next block" — a bundle of about 2,000–4,000 transactions that could be included in the next Bitcoin block (Bitcoin blocks are approximately 1MB, and each transaction takes a certain number of bytes).
Reading left to right:
| Color | Fee Zone | Description |
|---|---|---|
| Red/Orange | High priority | Highest fee rate — confirmed in next block |
| Yellow | Medium priority | Confirmed within a few blocks (15–60 min) |
| Green | Low priority | May take an hour or more |
| Blue/Purple | Very low | Could take hours or days in a busy mempool |
Fees on Bitcoin are measured in satoshis per virtual byte (sat/vB):
The mempool visualization shows the minimum fee rate to be included in each block-worth of space. If the "next block" requires 50 sat/vB, your transaction needs to pay at least that to be confirmed soon.
Above the blocks, you'll see the total mempool size in megabytes (MB) and the number of unconfirmed transactions. During busy periods:
You need the transaction ID (TXID) — a 64-character hexadecimal string like:
b6f6991d03df0e2e04dafffcd6bc418aac66049e2cd74b80f14ac86db1e3f0da
Your wallet shows this after sending. You can also find it by searching for an address (see below) and clicking a specific transaction.
Paste the TXID into the mempool.space search bar and press Enter.
Here's what each field means:
Transaction ID (TXID) The unique fingerprint of this transaction — a hash of all the transaction data. No two transactions have the same TXID. This is what you share to prove a payment.
Status
Confirmations The number of blocks mined after the block containing your transaction. Each new block adds one confirmation.
Fee Total transaction fee in satoshis and in BTC. Also shown as sat/vB (fee rate).
Fee rate Satoshis per virtual byte. Determines priority in the mempool. A higher fee rate gets confirmed faster.
Virtual size (vBytes) The "weight" of your transaction in virtual bytes. Determines how much you pay in fees. Factors affecting size:
Inputs (left side) The UTXOs being consumed. Each input shows:
Outputs (right side) New UTXOs being created. Each output shows:
Miner fee The difference between total inputs and total outputs. This goes to the miner who includes the transaction in a block.
Example reading:
INPUTS OUTPUTS
0.5 BTC from Address A → 0.3 BTC to Address B (payment)
0.19 BTC to Address C (change back to sender)
0.01 BTC fee to miner
Search for any Bitcoin address (starting with 1, 3, or bc1) to see its full history.
What you'll see:
Balance: Current BTC balance (sum of all unspent outputs — UTXOs — at this address).
Received: Cumulative amount ever received.
Sent: Cumulative amount ever sent.
Transaction count: Total number of transactions in and out.
Transaction list: Every transaction involving this address, sorted by block height (newest first). Each entry shows:
Important: Address balances and history are public by design. This is why privacy practices matter — if you reuse the same address and share it publicly, your entire financial history is visible to anyone.
If your transaction is unconfirmed, the transaction page shows:
Position in mempool: mempool.space shows approximately where your transaction sits in the queue. "Expected in X blocks" tells you roughly how long to wait.
Fee rate vs. current minimum: If the current "next block" requires 30 sat/vB and your transaction is at 10 sat/vB, your transaction is in the lower-priority queue. It will either be confirmed when congestion clears, or remain stuck.
What to do if a transaction is stuck:
Option 1: Wait. If the mempool clears (typically on weekends or low-traffic periods), even low-fee transactions eventually get confirmed. Bitcoin transactions don't expire — they stay in the mempool until confirmed or dropped (after about 2 weeks in most node implementations).
Option 2: RBF (Replace-by-Fee). If your wallet supports it (Sparrow, Electrum, BlueWallet), you can re-broadcast the same transaction with a higher fee. The new version "replaces" the old one if the miner accepts the higher fee.
Option 3: CPFP (Child Pays for Parent). If you're the recipient of a stuck transaction, you can spend the unconfirmed funds and attach a high fee to the new transaction. Miners are incentivized to confirm both the parent and child together to collect the combined fee.
Click any block in the mempool visualization (or search for a block height like 850000).
Block details:
Block height: The sequential number of this block in the chain. Block 0 is the genesis block (January 3, 2009).
Timestamp: When the block was mined (UTC). Note: block times vary — Bitcoin's protocol targets 10 minutes per block on average, but individual blocks can range from seconds to over an hour.
Mined by: The mining pool that found this block. Visible by the coinbase message or known pool addresses. Examples: Foundry USA, AntPool, F2Pool, ViaBTC.
Transaction count: Number of transactions in the block. Typically 1,500–4,000.
Size: Block size in bytes. Soft limit is approximately 4MB weight (1MB "base" + SegWit discount). Most blocks in 2026 are 1.5–2MB.
Difficulty: The mining difficulty at the time this block was found. Higher difficulty = more hash power required = more secure.
Nonce: The number the miner varied billions of times to find a hash below the target. This is the "work" in Proof of Work.
Coinbase transaction: The first transaction in every block. This is where the miner claims the block reward (currently 3.125 BTC after the 2024 halving) plus all transaction fees. The coinbase transaction has no inputs — it creates new Bitcoin from nothing (within protocol rules).
Merkle root: A hash of all transactions in the block. Changing any transaction changes the Merkle root, which changes the block hash, which invalidates the block.
mempool.space also shows a Lightning Network tab with:
The Lightning Network is a Layer 2 payment system built on top of Bitcoin. Transactions on Lightning don't appear as individual Bitcoin transactions (only channel opens and closes do). See Bitcoin Lightning Network Explained for more.
Transaction accelerator: During high congestion, mempool.space offers a fee-bumping service to accelerate a stuck transaction for a fee.
API: mempool.space provides a free, open API at mempool.space/api for developers to query block, transaction, and address data programmatically.
Self-hosted: mempool.space is open source (github.com/mempool/mempool). You can run your own instance connected to your own Bitcoin node for maximum privacy — your transaction lookups won't be logged by any third party.
Testnet / Signet: Switch to Bitcoin test networks for development purposes via the network selector.
Multiple languages: Available in English, Spanish, German, French, Portuguese, Japanese, and more.
Every time you look up an address or transaction on a public block explorer, the explorer's server logs your IP address alongside that lookup. If you're looking up your own addresses, this links your identity to those addresses in the explorer's logs.
For privacy-sensitive lookups:
This matters particularly for large holdings or addresses linked to your identity.
mempool.space is the best all-around explorer, but alternatives exist:
| Explorer | Strengths |
|---|---|
| mempool.space | Best fee visualization, mempool analytics, Lightning tab |
| blockstream.info | Clean interface, good address lookup |
| btcscan.org | Simple, fast |
| blockchain.com | Beginner friendly, long history |
| blockchair.com | Multi-chain, advanced filtering |
For pure Bitcoin use, mempool.space is the first choice of most technical users.
| What you want to find | What to search |
|---|---|
| Track a payment you sent | Transaction ID (TXID) |
| Check your wallet balance on-chain | Your Bitcoin address |
| See if a payment was received | Recipient's address |
| Understand current fee rates | Homepage mempool visualization |
| Verify a block was mined | Block height number |
| Research a wallet's history | Bitcoin address |
Can I see who owns a Bitcoin address? No. Bitcoin addresses are pseudonymous — the blockchain shows transactions but not identities. With chain analysis and off-chain data (exchange KYC, IP addresses), some addresses can be linked to identities, but the blockchain itself contains no names or personally identifiable information.
If a transaction has 0 confirmations, is it safe to accept? For small amounts (coffee, low-value purchases), 0-confirmation transactions are generally accepted in practice. For larger amounts, wait for at least 1–3 confirmations. For high-value transactions (real estate, large payments), wait for 6.
Why is my transaction not confirming? Most likely your fee rate is too low for current mempool conditions. Check mempool.space's homepage to see the current minimum fee for the next block. If your transaction is below that, it's in the low-priority queue.
What's the difference between block height and block time? Block height is the sequential number (position in the chain). Block time is the timestamp of when it was mined. Bitcoin targets 10 minutes between blocks on average, but individual gaps vary.
How do I know my hardware wallet received Bitcoin? Your hardware wallet's companion software (Sparrow, Ledger Live, etc.) scans the blockchain for activity on your addresses. You can also manually look up your receiving address on mempool.space to verify the balance and transaction history directly on-chain.
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