alt.hn

2/24/2026 at 3:50:54 PM

Show HN: Quantifying opportunity cost with a deliberately "simple" web app

 https://shouldhavebought.com/

by b0bbi

2/25/2026 at 10:21:32 AM

I first heard about bitcoin sometime in college (2007-2011). At the time I thought about buying a couple just for fun (might have been a few dollars worth? Can’t remember). But I decided it was a waste of money.

And at the time, it was a complete waste of money. I don’t regret it at all.

Only with knowledge of the future would it have been worthwhile.

But today when I see what cryptocurrency has become, I regret my decision even less.

There are countless ways I could have made millions if I knew the future. I don’t waste my time regretting those.

by nkrisc

2/25/2026 at 10:25:23 AM

I was gonna buy $1000 of bitcoin in 2016 but I couldn’t find my passport to verify my identity with Coinbase and then forgot about it. Ah well.

by jonplackett

2/25/2026 at 10:27:06 AM

Would you have $100k now or would you have sold it when it tripled to $3000 because that would've felt like a really good return already, though?

by rkomorn

2/25/2026 at 10:36:43 AM

Yeah this is the story I tell myself to make me feel better. I may well have even more regret! Or thought I was an investment genius and invested loads more and then sold it at a bad time.

by jonplackett

2/25/2026 at 11:52:59 AM

yeah as Warren Buffett once said: "Our favorite holding period is forever".

by b0bbi

2/25/2026 at 12:09:29 PM

That is basically my strategy. Everything I buy is with the intent of selling in a couple of decades when retirement comes, at the earliest.

by rkomorn

2/25/2026 at 12:46:00 PM

It's a great strategy as long as there's agreement between people and that the "S&P500" (paste your) means something :)

by b0bbi

2/25/2026 at 10:37:49 AM

would you keep it till today?

by b0bbi

2/25/2026 at 8:32:26 PM

Probably would have sold it when it doubled and felt like a genius… and then an idiot.

by jonplackett

2/25/2026 at 9:37:12 PM

yeh, that's true :) btw, I'm sure many did just that

by b0bbi

2/25/2026 at 8:33:31 AM

The first thing one has to do when analysing past money decisions is to judge the decision based on the information available at the time.

I too watched from the sidelines as btc, nvda and others went to the moon. But with the information available at the time, investing in those was not a sound strategy.

by PowerElectronix

2/25/2026 at 9:19:02 AM

Survivor bias again - these are the few that made it while many others did not.

by cs02rm0

2/25/2026 at 11:30:55 AM

Even if I would've bought Nvidia, Bitcoin, or whatever stock... who is to say I would've had the balls to hold it all the way to whatever they're at today. I probably would've ended up like the guy who spent 10,000 bitcoin on a pizza.

by lofties

2/25/2026 at 8:54:27 AM

It's true.

In my experience, you'll be able to evaluate the correctness of your actions today in about five years, when you have more data and results.

by b0bbi

2/25/2026 at 8:45:00 AM

There are plenty of people that thought WeWork would go to the moon, too.

by hsbauauvhabzb

2/25/2026 at 11:59:24 AM

You are 100% right about survivorship bias. That's actually exactly why the calculator already supports a status "BULLET DODGED"!

by b0bbi

2/25/2026 at 7:31:26 PM

Do you account for all the factors of the worldwide market? Because there are certainly more busts then there are crypto level books.

The whole pre-tense of your site is flawed by survivorship bias to the point where it has no value, and you suggesting you’ve accounted for that proves that you’re ignorant to economic realities.

by hsbauauvhabzb

2/25/2026 at 9:35:50 PM

Either I misunderstood the question, or you misunderstood what this project is about. All I consider is historical data. Based on this data and the dates entered, I calculate the result. I don't need to consider economics.

by b0bbi

2/25/2026 at 9:25:54 AM

hindsight is 20/20. If I'd known that Nvda, Aapl, Amzn etc. would go up, it's easy to now to regret how much money we'd have. Same thing with "RSU's" we get at FAANG. I often hear from coworkers that if they wouldn't have sold them when they got them, they'd be rich right now. Yes, they would be - but in an alternate universe, they'd have little/nothing and wouldn't have bought the car/camera/vacation they got out of the money when they sold the RSUs.

I added something related to this idea to my life-planning app: what if for projections. I track all my expenses/incomes/investments in my app. I then can with 1 click run a scenario where I move certain expenses to investments. I.e. cancelling netflix for 10 years, or xbox gamepass etc. and seeing what it would actually do to my 10 year projection (which already accounts for ETFs/Stock with variable return rates etc.). i.e.:

Exclude Recurring Expenses Simulate cutting these expenses and investing the savings Redirecting €19.99/month to investments

Then I see black on white what would happen if I get rid of all the 'small' subscriptions, on a visual chart. It's eye opening when one selects items that add up to a ~100 Euro ++ a month.

by Bishonen88

2/25/2026 at 9:55:40 AM

I tracked every single daily expense for a few years, until I hit a point where I realized I already knew exactly where my money was going and how much I could realistically save. It just comes down to discipline.

I really appreciate the idea and saved it for potential future features! My only hesitation is that adding practical projection tools might make shouldhavebought lose its fun, curious spirit and turn it into a serious financial app.

by b0bbi

2/25/2026 at 10:10:32 AM

You're right of course. For me the difference maker is in seeing on a projection chart that if I just cancel 2x zwift, disney and netflix, I can save up to:

Savings from Cuts

€11,048

€60/mo @ 8%

within 10 years. That's HUGE! While the 60 Euro a month seems kind of irrelevant on its own.

by Bishonen88

2/25/2026 at 12:12:05 PM

I applaud the technical journey, but I really do not understand the purpose. What's the point of knowing last week's lottery numbers?

by Propelloni

2/25/2026 at 12:24:05 PM

Think of it as art :) It’s an interactive museum of missed opportunities. We all know we can't change the past, but it's strangely entertaining to calculate exactly how much a 2015 pizza cost us in today's Bitcoin.

by b0bbi

2/25/2026 at 12:39:00 PM

Art needs no justification. So, well done ;)

by Propelloni

2/25/2026 at 10:20:50 AM

> He made a bold claim that one day it might reach $100k per coin. I remember thinking it sounded unrealistic - and even if it wasn't, I wasn't going to break my rule.

> ... The opportunity cost came out to tens of millions of dollars.

It doesn't sound, though, like you'd have held until 100k. This calculation only applies to people who'd have held for some reason; e.g. just after the conversation, you slipped into a coma and you just woke up now.

But I usually hear it from people who "could've bought at $2 but didn't!"

If you didn't buy at $2, you wouldn't have held at $4. If you didn't buy at $300, you wouldn't have held at $600. Etc.

Me neither fwiw :)

by nothrabannosir

2/25/2026 at 10:41:16 AM

Haha, or maybe the flash drive got lost in the junk at home :)

I would have sold it when I made X2 - good profit.

by b0bbi

2/25/2026 at 11:17:21 AM

Crudely, if my aunt had a dick she'd be my uncle.

In terms of feedback: - need BTC prices pre 2014 to really feel the pain - The date format for earliest date available is different to the date format then used in the input below

by intheitmines

2/25/2026 at 11:46:43 AM

You are 100% right about pre-2014 BTC. Any suggestion where to download trusted prices?

Regarding the date format - it can really cause confusion. Let me explaine. The "calculator" date format is "YYYY-MM-DD" (ISO 8601). But the input field's date format adapts based on your device settings. For better UX.

by b0bbi

2/25/2026 at 8:27:01 AM

Wouldn't this need to know what I actually did instead?

When I use it, it tells me that the form was incomplete. I tried to figure out how much I regret having bought 0 bitcoin so far.

Perhaps needs a better error message? I think it actually doesn't like the zero, but prevents it doesn't like incomplete data. Zero is also a number.

> CAUSALITY_ERROR: You cannot SELL before you BUY.

https://en.wikipedia.org/wiki/Short_(finance)

Needs at least a better error message that short sells aren't supported, instead of trying to be too clever by half about causality.

by eru

2/25/2026 at 8:49:50 AM

Thanks for the "zero", it really does matter in a calculator like this.

Fair point on the shorting - I definitely prioritized retro drama over actual market mechanics there!

by b0bbi

2/25/2026 at 10:56:39 AM

fixed, btw

by b0bbi

2/25/2026 at 9:24:03 AM

Why stop at financial loss? I did https://whentheywere.com - enter your DOB and get a feel on how you compare to Einstein, Michael Jordan, Steve Jobs and others.

Here's one for 01/01/1990: https://whentheywere.com/?date=1990-01-01

You can subscribe to a calendar and get notified when you are exactly the age someone was, when they achieved something.

by con

2/25/2026 at 12:05:12 PM

The opportunity cost is what I can do instead. The opportunity cost of investing is just a 3% return really. So much that we do in life is just throwing the money away though. You should just go to work, invest all your money, then when you are 65 you will be able to live off your savings.

by z3t4

2/25/2026 at 12:30:42 PM

I spent 20 years of my adult life on a cold and calculating lifestyle (as you described), I can’t say that I was unhappy, but one morning I woke up and realized that everything that had been acquired was lost due to circumstances beyond my control.

So?

by b0bbi

2/25/2026 at 9:47:41 AM

Most reasonable people will not have enough conviction to make a serious amount of money even if they’re right. I think a better question is how much would you have invested to make $500k/ $1mn (or whatever a life changing sum is for you) on the investment then you can consider whether you had the stomach to do that.

by jbjbjbjb

2/25/2026 at 10:45:56 AM

By the way, a "Reverse Mode" (calculating the initial stake needed to hit exactly $1M) is actually a brilliant idea.

But to your underlying point - it's the hard truth. People often act like they have infinite time and keep putting decisions off for "later". And then, boom - your peak earning years are behind you, boom - you're 70. This terminal is basically a receipt for that exact kind of procrastination.

by b0bbi

2/25/2026 at 1:22:53 PM

It is sort of brilliant (thanks btw) but also stupid to think about. It is easy for people to simply put a sensible monthly amount in a low cost fund and given enough time and steady contributions make life changing amounts of money (early retirement, house upgrade, child’s school or college paid for etc). And all without needing to take a big bet at any point.

by jbjbjbjb

2/25/2026 at 1:42:11 PM

You are welcome:)

This works as long as everything is good and stable, at least with the economy. But in the long run (decades), it still works. You just have to survive.

by b0bbi

2/25/2026 at 12:28:12 PM

If you'd bought every fad coin your brother recommended to you, even though it was a bad idea in your own judgement then I think you'd have zero dollars.

by fancyfredbot

2/25/2026 at 12:36:39 PM

My brother is not a crypto guru, we just discussed about BTC. It was a philosophical conversation in the spirit of perhaps it will become an alternative to conventional money, then it could greatly increase in value.

But I agree that buying new coins is like buying lottery tickets - if you buy all the tickets, there will be no money left.

by b0bbi

2/25/2026 at 9:20:31 AM

This is quite a fun website, what have you used for the backend, i've been wanting to get more deployments for small web tools but the hug of death always worries me

by endymion-light

2/25/2026 at 10:56:06 AM

I'm unsing Laravel. I think any framework you are familiar with will do. I'm using frameworks even for single page application, cuz you never know how it turned.

I think the danger of "hug of death" is overblown. Hardware gets more powerful over time, and bandwidth expands. I had a project with about 60k unique users per day, and that traffic lasted for several weeks. I didn't take any special measures, although I was prepared to switch to a more powerful server.

I'd be worried about what to do to get to 60k users. :)

by b0bbi

2/25/2026 at 2:24:30 PM

Maybe add something more based as a comparison? MSCI World or similar

by Garlef

2/25/2026 at 2:50:37 PM

do you mean popular shares?

by b0bbi

2/25/2026 at 9:20:10 AM

Oh good grief. $2.5m. That’s pretty funny. Hard to imagine I would have held through the ride but a pretty penny nonetheless. Not as bad as my buddy who sold his $200k grant in 2017 to buy a San Jose townhome that costs exactly the same today hahaha!

by renewiltord

2/25/2026 at 10:05:02 AM

Ouch, that San Jose townhome story is actual physical pain.

WELCOME TO REALITY. IT’S EXPENSIVE.

by b0bbi

2/25/2026 at 9:30:20 AM

Is it $149 or $149000?

by dvh

2/25/2026 at 9:57:48 AM

if the system wrote $149 this mean $149 or you found a bug. Please let me know if found a bug.

by b0bbi

2/25/2026 at 10:52:23 AM

It wow 149,000

by dvh

2/25/2026 at 11:19:20 AM

149,000 mean 149000

by b0bbi

2/25/2026 at 11:57:17 AM

It's true, most investors quit right before they're about to hit it big!

...or alternatively, you live a decent life without associating with any of this.

by rf15

2/25/2026 at 12:19:03 PM

Ah, the classic "99% of gamblers quit right before they win big" mindset! :)

But honestly, your second point is the ultimate truth. Ignorance truly is bliss. The happiest people are usually the ones who have zero idea what the current price of Bitcoin or Nvidia is, not even BTC or NVDA, hehe.

by b0bbi

2/25/2026 at 10:28:52 AM

My question is, why would you do that to yourself? Living with regrets of the past that would never have been, anyway, seems like a recipe for sadness and despair. Maybe my sense of fun or humor or whatever is off, but I just don't get doing this to yourself, man. You could have hooked into them and thought $1,000 is the highest it'll go and sold them all them. Who knows‽

No offense meant. Just my two Satoshis.

by fragmede

2/25/2026 at 11:05:03 AM

Honestly, it's mostly just dark humor and a bit of financial "exposure therapy". Sometimes seeing the absurdly huge, multi-million dollar number makes the regret feel almost comical rather than actually depressing.

But you are 100% right about the $1k mark. In reality, almost none of us would have held to the top. We would have sold the moment it doubled, bought new iphone and felt like geniuses. That's the reality this calculator conveniently ignores for the sake of the joke!

Appreciate your two Satoshis!

by b0bbi

2/25/2026 at 9:13:01 AM

[dead]

by time2buybitcoin