If Your Stack Could Pay Off Your Mortgage, Would You?

Part 1 of 2 in Bitcoin and the House. Reddit's money fight argues that it's about the interest rate. We think the bigger variable is when to do it. Lending rates verified as of July 28, 2026.

When a Reddit user asked whether they'd sell a slice of their stack to pay off the house, the thread turned into a debate. Roughly 45% said never. Their 2.75% and 3% mortgages were cheap money. A smaller camp wanted the debt gone at any price. The rest said it depends. Nearly everyone argued about a single number: the interest rate.

The rate matters, but the decision tree starts before that. Can you afford to wait, and where we are in the cycle, are better starting points. Since mortgage payoffs are priced in dollars and paid in bitcoin, the opportunity cost swings widely across the cycle. Similarly, income and expenses can also swing depending on job status, tuition bills, and unexpected liabilities.

For the purposes of this analysis, we will use a worked example throughout.

1. Affordability, and Which Way It's Heading

Start with the house, not the stack. One ratio does the work:

Why 2.2 and not 1? Because the mortgage isn't your only bill. Take-home pay also covers groceries, gas, insurance, the car, the kids. For a typical household those fixed costs eat roughly half of income, so the budget actually breaks even on cash flow when the payment reaches about 45% of take-home. That's C = 2.2. Below that line, the household is quietly borrowing from somewhere else to keep the house.

The snapshot matters less than the direction. C falls when income slips, or when the payment creeps up with taxes and insurance. If yours is drifting toward 2.2, selling bitcoin starts becoming an option worth looking at. If it has already broken 2.2, selling the minimum makes sense: a $100,000 paydown costs about 1.8 BTC at today's price, drops the required payment, and buys back the margin the budget lost. Survival outranks CAGR.

Our example household earns $8,500 against a $2,500 payment. C = 3.4, and stable. They have the luxury of choice, which is what the rest of this article prices.

2. Where's the Cycle?

Now the stack. You can't hand the bank $400,000 by selling $400,000 of bitcoin. The sale is taxable, so using our example, clearing the debt means liquidating about $479,000 of bitcoin: 7.4 of the 10 BTC, with a tax bill near $79,000 on gains realized in a down market.

Ten months ago, at the October peak of $126,000, the identical payoff cost 4.0 BTC.

So the cycle question splits in two. Closer to the bottom, it isn't whether to sell. It's how long you can last before the upswing. The last two cycles bottomed near month 12 after their peaks (December 2017 to December 2018, November 2021 to November 2022) and staged real recoveries in months 18 to 30. We're at month 10, so call the runway 8 to 20 more months. If C holds that long, waiting is cheap: 12 months of interest runs about $25,600, covered if bitcoin finishes roughly 5% higher. And the ladder rewards patience with less bitcoin sold at every leg: 5.4 BTC at $90,000, 4.5 at $110,000, 4.0 back at the peak.

Closer to the top, the logic flips. That's when the payoff is cheapest in BTC, and selling into strength saves nearly half the stack cost of selling into weakness. Price two things before pulling the trigger. First, the tax: a low-basis stack pays up to about $101,000 on this payoff. Second, the rebuy: if the plan is to repurchase in the next trough, you've turned a payoff into a round trip with execution risk. Plenty of people nail the sale and miss the re-entry.

3. The Cost of Capital

Only now does the Reddit argument enter. Paying off a 6.4% mortgage earns a guaranteed, tax-free 6.4%, so bitcoin must beat 6.4% to justify holding.

In our example H is 5.3%, not 6.4%. Basis moves both numbers. A $50,000-basis buyer from last cycle pays about $23,000 in tax on the payoff and faces a 6.0% hurdle. A $10,000-basis early stack pays about $101,000 and faces 5.1%. Deeper gains, bigger toll, lower bar.

Selling today's 7.4 BTC instead of the peak's 4.0 hands over 3.4 extra BTC to clear the same $400,000 of debt. If price round-trips to the old high, that's roughly $428,000 of stack spent retiring $400,000 of mortgage. The cycle doesn't change what you owe. It changes what the payoff costs you.

Now the rate. A 2.75% mortgage nets a hurdle near 2.3%, and bitcoin has cleared 2.3% in every rolling 4-year window it has ever printed. Debt like that is about as close to free money as a household gets. You service it, let the stack ride, and nearly half that Reddit thread had this exactly right. At 7%, the hurdle runs 5.3% to 6.6%, and bitcoin's weakest 4-year stretches landed in the single digits, right on that line. That's a fair fight. It gets settled by Questions One and Two.

One more job for H. It also prices the wait from Question Two:

History's recoveries from this depth paid multiples of 5.3% a year. If this cycle breaks the rhythm and the price just sits, every flat year adds one hurdle-year to the bill. Pattern, not promise.

The Other Door: Borrowing Against the Stack

The thread's favorite alternative: borrow against the bitcoin, keep the stack, kill the mortgage. The arithmetic is unkind right now. Bitcoin-backed lenders in the BoB Rate Index charge 8.75% to 11.49% on a standard 50% LTV loan, 10.42% on average as of July 28. Swapping a 6.4% mortgage for 10.42% bitcoin-secured debt runs about $16,000 a year in negative carry on $400,000, and $9,000 even at the cheapest lender. It also trades a loan that can't be margin-called for one that can. Only on-chain rates (4.38% TVL-weighted, and variable) undercut the mortgage, at the price of automatic liquidation and nobody to call.

So at today's rates the borrow path isn't a payoff engine. It's a bridge for the household whose C won't hold the runway: defer the forced sale out of the trough, revisit near the top, pay for the time. If that's the door you're considering, the mechanics of pledging bitcoin against a house are worked through in our guide to bitcoin-backed mortgage loans, which covers the three structures on offer and which of them can margin call you. A fourth door is opening too, and we'll keep it brief: bitcoin that earns yield can help carry debt on its own. When the yield on the stack clears the cost of the debt, the loan starts servicing itself, and the whole mortgage calculation changes.

The Order of Operations

Affordability first: compute C and watch its direction. Below 2.2 or falling toward it, sell the minimum and recast. Cycle second: near the bottom, the question is whether C outlasts the 8-to-20-month runway to recovery; near the top, the sell window is open once you've priced the tax and the rebuy. Cost of capital last: a sub-4% mortgage nets a hurdle bitcoin has never lost to, so hold what's closer to free money, while a 7% mortgage is a fair fight the first two questions settle. Here's the whole decision on one page:

Everything above assumes the mortgage already exists. If you are on the other side of it, buying rather than paying off, the same tax logic runs in reverse: pledging bitcoin is not a disposition, which is why the crypto-collateralized mortgage structures exist at all, and why the Coinbase and Better program credits BTC at 40% of market value rather than lending against it at par. The broader case for borrowing instead of selling is in bitcoin loans versus selling.

Stay tuned for Part 2: paying off the mortgage with BTC yield. Not whether to kill the loan, but how to service the monthly payment from a stack without selling the stack, and what that costs across structures.

Steven Han and Michael Song are the co-founders of Borrow/On/Bitcoin, an independent comparison publisher for bitcoin-backed lending. Lending figures verified by the BoB Rate Index, July 28, 2026; the 6.4% mortgage figure reflects the average 30-year fixed rate in late-July industry data; historical cycle dates from public market data. This article is general information, not investment or tax advice; capital-gains rates vary by income and state. BoB is not a lender and may earn referral fees from lenders it compares; lenders cannot pay for placement or ranking.