The best way to back up a seed phrase is to stamp it into stainless steel, store the metal somewhere separate from your hardware wallet, and never photograph or type it anywhere. Paper is fine until the day it isn’t — and the day it isn’t is usually a fire, a flood, or simply a decade of slow fading in a drawer. Your seed backup is the only thing that recovers your Bitcoin if the device is lost, stolen, or breaks, so it deserves to be the most durable object you own.
Here’s the reasoning, and the honest version of which product to buy.
Why paper isn’t enough
Every hardware wallet ships with a paper recovery card, and writing your seed on it is the correct first step. But paper has three failure modes that all end the same way — coins gone, no recovery:
- Fire. Paper ignites at around 230°C. A house fire runs far hotter. The card in your desk drawer is ash.
- Water. A flood, a burst pipe, or a leaky roof turns ink into an unreadable smear.
- Time and discovery. Ink fades, paper yellows, and a loose card is easy for someone to find, photograph, or throw out by accident.
Jameson Lopp’s well-known metal-seed stress tests (fire, crush, corrosion) exist precisely because the community learned this the expensive way. The takeaway from years of those tests: a good steel backup survives conditions that destroy paper, and the differences between steel products are smaller than the difference between any steel and paper.
What makes a good steel backup
Not all metal backups are equal. What to look for:
- Stamped or punched, not printed. You want the letters physically deformed into the metal with a punch or pre-cut tiles — not ink, not a sticker, not surface etching that can wear off.
- Stainless steel (304 or better), which resists both heat and corrosion.
- Simple and legible. Some “puzzle tile” kits are fiddly and easy to assemble wrong under stress. The best designs make it hard to record your words incorrectly.
- Records the full word or the BIP-39 number. Either the first four letters of each word (enough to identify it uniquely in the BIP-39 wordlist) or the word’s index number.
The pick
If you’re already in the Trezor ecosystem — which, if you followed our hardware wallet advice, you are — the Trezor Keep Metal is the clean choice. It stamps each word into 304 stainless, ships flat-packed, and pairs with the device order so the seed never sits on cardboard longer than it has to. It’s the same backup I recommend at the end of every Trezor review for one reason: it’s the highest-return security upgrade you can make after the device itself.
That said, the honest framing: any quality stamped-steel backup beats paper. Don’t let shopping for the “perfect” one delay you. The risk isn’t picking the second-best steel plate — it’s leaving your only backup on a card that a candle could erase.
How to do it safely
- Stamp offline. Transfer the words from your device’s screen (or your paper card) to the steel by hand. Never type them into a computer or phone, never photograph them.
- Store it separately from the device. A thief who gets both your hardware wallet and your seed backup has everything. Keep the metal in a different location — a safe, a relative’s house, a bank box.
- Consider a passphrase or Shamir backup for larger amounts. A SLIP-39 Shamir backup splits the seed into multiple steel shares, so no single location is a single point of failure. For inheritance and geographic distribution, this is the next level up.
- Test recovery once. Before you trust it, confirm the words on the steel actually restore your wallet (on the device, offline).
The bottom line
Buy the hardware wallet, then immediately buy a stamped-steel backup and move your seed onto it. For Trezor users that’s the Trezor Keep Metal; for anyone else, any quality stamped-stainless plate. It’s a $30-80 purchase that converts your single biggest point of failure — a flammable paper card — into the most durable object in your house. Do it the same week you set up the wallet, before the cardboard becomes the weakest link.
Related reading
- What if I lose my seed phrase? — why this backup is the whole ballgame
- Trezor Safe 3 review — the device this backup protects
- BIP-39 recovery phrase — the security bible — what your words actually encode
- Move Bitcoin off an exchange to a hardware wallet — the step before this one
- Best hardware wallet for beginners — if you don’t have a device yet