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There’s no shortage of hardware wallets on the market today, but if you're serious about Bitcoin, and Bitcoin only, then the Coldcard MK4 likely sits near the top of your shortlist. Designed by Coinkite, the MK4 strips away distractions like altcoin support or internet connectivity, leaving behind a focused, deeply secure, and battle-tested cold storage tool.

I’ve used several hardware wallets over the years, including earlier Coldcard models. However, I began my deeper journey with the Coldcard Q, and that set a high bar for measuring the MK4 against. Below is my full experience setting up and using the Coldcard MK4, where it excels, where it’s beginning to show its age, and why its former dominance is now being challenged by its sibling.

Pros & Cons

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Coldcard MK4 Quickspecs

• Manufacturer: Coinkite - Canada
• Type: Bitcoin-only Hardware Wallet
• Release Year: 2022
• Price: $177.94
• Air-Gapped Operation: Yes – via microSD card and/or NFC
• Display: Bright 128x64 pixel OLED screen
• Keyboard: Numeric Keypad
• Secure Element: Dual SEs (Microchip ATECC608A + SAM3X8E MCU)
• Power Options: USB-C with optional 9V battery adaptor (none included) 
• Connectivity: USB-C (data + power), microSD, and NFC
• Multisig Support: Yes (PSBT, compatible with Sparrow, Nunchuk, etc.)
• Passphrase Support: Yes, ideal for decoy wallets
• Secure Backup: BIP39 seed phrase + optional encrypted backups to microSD
• Firmware: Open-source (Coldcard’s proprietary system, written in MicroPython)
• Special Features:
  
  • USB virtualization for PSBT file transport 
  • Encrypted notes + PIN login delays
  • Brick Me PIN feature (self-destruct mechanism)
  • Dice roll entropy input (DIY randomness for seed gen)

How I Used the Coldcard MK4

Step 1: First Boot and Setting Up PIN Protections

The MK4 powers up via USB-C or via a ColdPower adapter (which lets you use a 9V battery, an odd but clever solution). I went with the ColdPower ($25; not included) and the USB-only cable ($17; not included) for a fully air-gapped operation.

After booting, I chose a secure PIN. The Coldcard uses a two-part PIN system: a prefix and a suffix, separated by an anti-phishing word shown on-screen after entering the prefix. I then set up a duress PIN that opens a decoy wallet and a Brick Me PIN, which will completely wipe the device on use—perfect if someone forces access under threat. You don’t have to enable these, but I wouldn’t consider a Coldcard complete without them.

These protections are especially important for long-term Bitcoin holders who anticipate dramatic BTC price changes by 2030, including widely circulated Bitcoin price predictions of $1 million per coin made by Robert Kiyosaki, Michael Saylor, Raoul Pal, and Cathie Wood. As the value of your holdings increases, so does the importance of your security setup.

Step 2: Creating a Watch-Only Wallet via NFC

Next, I generated a new seed on the MK4 and saved an encrypted backup to the microSD. To prepare for my first deposit, I used the built-in NFC function (manually enabled) to export the wallet's xpub to the Nunchuk app on my Android phone. Within seconds, I had a functional watch-only wallet that could generate Receive addresses and monitor balances without compromising any private key material. That was my first deposit.

Step 3: Making My First Transaction with microSD

When it was time to move funds, I used Sparrow Wallet on my desktop. I crafted a PSBT (Partially Signed Bitcoin Transaction) for sending BTC out, exported it to the microSD, and inserted the card into the MK4. After verifying each transaction detail on the MK4’s color screen, I signed it, saved the signed PSBT back to the card, and returned it to Sparrow for broadcasting.

Rating (Overall: 4.1/5)

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Coldcard MK4: The Air-Gapped Standard's Starting Point

As someone who started with the Coldcard Q, stepping back to the MK4 feels like visiting an older, more minimalistic relative. The MK4 has all the essentials: robust security, full air-gap capabilities, great multisig support, and granular control over your funds. It was, without a doubt, the best Bitcoin-only hardware wallet of 2022 and most of 2023.

But here’s the thing: everything great about the Coldcard MK4 is also present in the Coldcard Q—and then some.

For about $70 more, the Coldcard Q gives you:

• A larger, easier-to-read screen
• A full physical keyboard
• Built-in QR code scanner (not fast, but usable)
• Internal power via 3x AAA batteries—no ColdPower adapter, 9V or USB cable needed
• The same excellent NFC + microSD air-gap workflows

That makes the MK4 feel a little boxed in. At its current price of $177.94 + $17 for the power-only USB cable, it sits uncomfortably close to a superior product that fixes many of its limitations. If the MK4 were priced closer to $100, it’d be a no-brainer for secure, no-frills Bitcoin cold storage. But where it stands now, the Q overshadows it in nearly every way.

Lukas is your trusted guide for navigating the best crypto hardware wallets of 2025. Their deep dives cut through the noise, empowering you to protect your digital assets. Explore more of their invaluable resources here:

• Best Bitcoin-Only Hardware Wallets of 2025 – For maximalists who value simplicity and sovereignty.
• Best Metal Seed Phrase Backups in 2025 – The only way to protect your seed words from fire, water, and time.
• Top 20 Hardware Wallets for Crypto Cold Storage – A complete guide to the most secure and trusted devices available today.
• Best Biometric Hardware Wallets in 2025 – Because privacy and convenience don’t have to be opposites.
• Best Credit Card-Sized Hardware Wallets in 2025 – Perfect for semi-cold storage and covert carry.
• Top 6 Hardware Wallets for NFTs in 2025 – Yes, even your digital collectibles deserve cold storage.

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FAQs

• What is the Coldcard MK4?

The Coldcard MK4 is a highly regarded hardware wallet developed by Coinkite, a Canadian company dedicated to Bitcoin-specific security. It's built for air-gapped operation, meaning it can sign Bitcoin transactions without ever directly connecting to an internet-connected computer, maximizing security. 

• Is the Coldcard MK4 the best Bitcoin hardware wallet?

The Coldcard MK4 is one of the most secure Bitcoin-only hardware wallets on the market, but whether it's the best Bitcoin hardware wallet depends on your priorities. If you're looking for maximum security, air-gapped operations, and Bitcoin-only support, it’s a strong contender. However, for those prioritizing ease of use, QR code support, or a friendlier setup, other options might suit them better. Check out our guide to the Best Bitcoin-Only Hardware Wallets of 2025 for a complete breakdown.

• Is the Coldcard MK4 a Bitcoin Lightning wallet?

No, the Coldcard MK4 is not a Bitcoin Lightning wallet and is not compatible with Bitcoin Lightning network wallets. It is designed specifically for cold storage of Bitcoin on-chain.

• Do I need a microSD to sign transactions? 

Not strictly, you can also sign using NFC cards or directly from the device. But microSD signing remains the fastest and most frustration-free method for large PSBTs.

• What are the current Bitcoin price predictions?

There’s no shortage of Bitcoin price predictions from analysts, economists, and Bitcoin maximalists. Long-term forecasts are especially popular:

• BTC price 2030 projections by figures like Michael Saylor, Cathie Wood, and Arthur Hayes commonly point to $1 million per Bitcoin.
• PlanB's Bitcoin price prediction using his stock-to-flow model places BTC above $500,000 within this decade.
• More conservative models estimate the Bitcoin price in 2026 between $150,000 and $250,000, factoring in post-halving market cycles.

Whether these projections materialize or not, they serve as useful reference points for long-term holders planning UTXO management, address segregation, and wallet backup strategies.

• Will Bitcoin crash to zero?

The idea that Bitcoin will go to zero is a common concern, but highly unlikely. For BTC to crash to zero, it would require a catastrophic bug in the protocol or a complete loss of global demand. Given Bitcoin’s distributed and immutable ledger, paired with strong institutional, sovereign, and retail ownership, a total collapse is improbable. Even in a severe network failure, the system could likely be rolled back to a prior state. In short, will Bitcoin crash to zero? It's theoretically possible—but practically implausible.

• How can I buy Bitcoin without an ID or verification?

If you're looking to buy Bitcoin without ID or buy Bitcoin online without verification, there are several privacy-respecting peer-to-peer (P2P) platforms available. HodlHodl, Bisq, and Peach Bitcoin offer users the tools and tutorials on how to buy Bitcoin anonymously, without the need to upload government documents or complete KYC procedures. These methods are ideal for funding your Coldcard MK4 securely and privately, though they often come with slightly higher premiums.

• Should I buy Bitcoin before or after the halving?

Historically, buying Bitcoin before the halving has been more profitable, but not always immediately. Price action often lags the event, with major moves occurring 6–18 months later. So, should you buy Bitcoin before or after the halving? Honestly, the best time was four years ago—the next best time is probably now. For peace of mind, many opt for regular dollar-cost averaging (DCA) regardless of timing.

Testimonials

Special thanks to Crypto Guide and BTC Sessions for their in-depth tutorials. Their content was invaluable in helping me confidently set up and use my Coldcard MK4 the right way:

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