eth_blockNumber on Ethereum
Everything below was measured on 2026-10-13 by calling eth_blockNumber on Ethereum through the same endpoint customers use, and is re-measured weekly.
What eth_blockNumber does
Returns the number of the most recent block the node has, as a hex string. It is the cheapest way to tell whether a node is keeping up and the usual starting point for polling a chain.
eth_blockNumber on Ethereum: what we measured
| Head block when measured | 26,183,536 (0x18f8770) |
|---|---|
| Age of that block when read | 5 s |
| Average block time (last 1,000 blocks) | 12 s |
| "safe" behind the head | 41 blocks (about 8 min) |
| "finalized" behind the head | 73 blocks (about 15 min) |
What this means for polling
With 12 s blocks, polling more often than every 12 seconds mostly returns the same number and spends requests for nothing. viem's default polling interval of 4 seconds is already shorter than one block on Ethereum.
The number eth_blockNumber returns is the newest block, which can still change in a reorg. On Ethereum, "finalized" was 73 blocks (about 15 min) behind it and "safe" 41 blocks behind. Use eth_getBlockByNumber("finalized") when you need a height that will not change.
Example request
curl -s https://rpc.swiftnodes.io/rpc/eth?key=YOUR_API_KEY \
-X POST -H "Content-Type: application/json" \
-d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber","params":[]}'import { createPublicClient, http } from "viem";
const client = createPublicClient({
transport: http("https://rpc.swiftnodes.io/rpc/eth?key=YOUR_API_KEY"),
});
const head = await client.getBlockNumber(); // bigint
// Follow the chain: poll about once per block (12 s on Ethereum)
const unwatch = client.watchBlockNumber({
pollingInterval: 12048,
onBlockNumber: (n) => console.log("new head", n),
});Other methods on Ethereum
- eth_chainIdSupported
- eth_getBalanceSupported
- eth_getBlockByNumberSupported
- eth_getTransactionByHashSupported
- eth_getTransactionReceiptSupported
- eth_callSupported
- eth_estimateGasSupported
- eth_gasPriceSupported
- eth_maxPriorityFeePerGasSupported
- eth_sendRawTransactionSupported
- eth_getTransactionCountSupported
- eth_getCodeSupported
- eth_subscribeSupported
- eth_getLogsSupported
- eth_getBlockReceiptsSupported
- eth_feeHistorySupported
- eth_getProofSupported
- eth_createAccessListSupported
- debug_traceCallSupported
- trace_blockSupported
- trace_transactionSupported
eth_blockNumber on other chains
- Base
- Arbitrum
- Optimism
- Polygon
- BNB Smart Chain
- Avalanche
- Sonic
- Linea
- Scroll
- zkSync Era
- Blast
- Mantle
- Gnosis
- Celo
- Berachain
- Monad
- Unichain
- Kaia
- PulseChain
- World Chain
- Ronin
- Abstract
- ApeChain
- MegaETH
- Fantom
- Lisk
- Hemi
- X Layer
- BOB
- Plasma
- Fraxtal
- Zora
- Story
- Soneium
- Sei
- Hyperliquid
- Taiko
- Morph
- Ink
- Katana
- Ethereum Classic
- opBNB
- Mode
- Flare
- Core
- Chiliz
- Telos EVM
- Tempo
- Cronos
- Manta Pacific
- Shibarium
- Boba Network
- Arbitrum Nova
- Immutable zkEVM
Frequently asked questions
Does Ethereum support eth_blockNumber?
Yes. eth_blockNumber answered on the SwiftNodes Ethereum endpoint when our weekly probe called it through the customer path (2026-10-13).
How fast are blocks on Ethereum?
About 12 s per block, averaged over recent blocks (measured 2026-10-13).
How often should I poll eth_blockNumber on Ethereum?
About once per block, every 12 s. Faster polling mostly returns the same number.
Ethereum endpoints, live block height and WebSocket status are on the Ethereum RPC page.
One key covers every chain we serve, and SwiftNodes has a free tier.