Let a wallet fill in your ETH address by scanning
Paste your Ethereum address and this makes a code that a wallet scans to pre-fill the recipient field — and, if you add an amount, the value too. It kills the single scariest step in crypto: hand-copying a 42-character hex address where one wrong digit sends funds into the void forever.
There's a catch no wallet warns you about at scan time: the code carries an address, but not a guarantee of which network the sender is on. Ethereum-style addresses are identical across many chains, so the pattern that protects you from typos does nothing to stop a wrong-network transfer.
The chain-mismatch trap
The same 0x address exists on Ethereum mainnet, on layer-2s like Arbitrum and Optimism, on Polygon, and on other EVM chains. The QR encodes the address, so a scanner on the wrong network will happily send there — to your address on a chain where you may not control the keys, or where the funds are far harder to recover.
The code can't enforce the network. State it in plain text next to the code — 'Ethereum mainnet only' — and confirm the sender's wallet is set to the right chain before they hit send.
What the wallet shows on scan
A wallet reads the code and drops your address into the To field, with the amount pre-filled if you included one. The sender still reviews, sees the gas estimate, and confirms — nothing moves automatically. Good wallets show the address in full so the sender can eyeball the first and last few characters against what you published.
- Address lands in the recipient field, ready to check.
- Amount, if set, appears as a suggested value the sender can edit.
- Gas and the final confirmation stay entirely with the sender.
Wei, ether, and how the amount displays
Ether is the human unit; wei is the smallest indivisible unit, and one ether is 10^18 wei. Payment formats often express the amount in wei under the hood, which is why an amount can look like an enormous integer in the raw payload even though the wallet displays a tidy figure in ether.
Enter the amount as ether here — a normal decimal like 0.05 — and check that the wallet echoes the same 0.05 ETH on its confirmation screen, not a figure shifted by decimal places.
When to leave the amount blank
For a donation jar or a tip code, omit the amount and let the sender choose. Fixing an amount only makes sense for a set price. An empty amount also makes the payload shorter and the code a touch bolder — and it dodges any wei-versus-ether display confusion entirely.
How to make an Ethereum payment QR code
- Paste the address. Copy the full 0x address rather than typing it, and check the first and last four characters. This code prevents typos only if the address you paste is itself correct.
- Add an amount, or don't. Enter the value in ether as a decimal, e.g. 0.05. Leave it blank for a donation code where the sender decides how much to send.
- Label the network in plain text. The code can't lock the chain, so print 'Ethereum mainnet' beside it and tell senders to check their wallet is on that network.
- Test with a real wallet. Scan it and confirm the address and amount appear correctly — and that the amount reads in ether, not a wei-shifted figure — before publishing.
Technical details
- Maximum characters: 2953
- Recommended error correction: Q (quartile) — the higher default keeps a payment address readable even if the printed code is scuffed or carries a small logo.
- Payload format: ethereum:<address> with an optional value parameter appended when an amount is set.
- The address alone doesn't fix the chain — the same 0x address is valid across many EVM networks, so the sending network must be confirmed separately.
Frequently asked questions
- Can someone send from the wrong network by scanning this?
- Yes, and it's the real danger. The code holds your address, which exists identically on Ethereum, Polygon, Arbitrum and other EVM chains. A wallet set to the wrong network will send there. The QR can't enforce the chain, so label it in plain text and have senders verify their network.
- Does scanning send the ETH automatically?
- No. The wallet only pre-fills your address, and the amount if you set one. The sender still reviews the recipient, sees the gas estimate, and confirms manually. Nothing leaves their wallet until they approve it, so the code is safe to publish openly.
- Should I enter the amount in wei or ether?
- Enter it in ether as a plain decimal, like 0.05. Wei is the smallest unit — one ether is 10^18 wei — and some payload formats carry the value in wei internally, which is why raw amounts look huge. Confirm the wallet displays your intended ether figure.
- What if I leave the amount blank?
- Then the wallet pre-fills only your address and the sender chooses how much to send — ideal for donations or tips. It also shortens the payload slightly, makes the code a bit bolder, and removes any risk of wei-versus-ether display confusion on the amount.
- Does the QR protect me from a wrong address?
- It protects the sender from mis-typing the address you gave — that's its main value. It cannot check the address is yours or correct in the first place. Always paste, never retype, and verify the first and last four characters before you publish the code.
- Can I change the address or amount after printing?
- No. Both are fixed in the pattern, so a new wallet or price means a fresh code. There's no server behind it to update, which is also why the scan works without any connection.