Buying a new house and don't want to take out a loan. House and stock prices are a crap shoot. So, have to decide. I'll miss 3 or 4 hundred a month in dividends, but should make out in the long run. Last time I took out a bridge loan on my house and got lucky and it sold right away and had only made one payment.

Vanguard pulled a ha-ha funny on me in December. There was a huge slug of sales that month. I had until January 15 to make an estimated payment. I ended up wildly overpaying. I’ll bet I get hit with a penalty anyway, just because.

It’ is seriously impossible to come up with an accurate estimate without going through a Capital Gains worksheet or a Schedule D worksheet. I’d send you an Excel worksheet, but even I was able to write one. Once you’ve got it, it works year after year, with minor changes.

Suggestion: move the discussion to the Personal Finance, where it will get more attention.

Full disclosure: I am not an accountant.

Best wishes.

for income over $94,000. But I don't know if you are taxed on all of the gains. With some taxes, the rates apply only above an amount. Like marginal rates, if you are in the 24% bracket, that applies to earnings over $100,000, the uincome beforte that is taxed at a lower rate.
Also you might have State taxes.

If you are filing individually, the tax rate on long term capital gains is 15 percent if your taxable income is above $48,350 but less than $533,400. If you’re filing jointly the 15 percent rate kicks if you have taxable income above $96,700. Below the threshold the tax rate is 0 percent

Note that some states impose capital gains taxes and even if you are below the federal threshold you might still owe state capital gains tax

Doubt if there will be much gain on the one I'm selling.

Thinking about selling stocks on Monday.

There's no one simple way to predict what you will owe. It depends on the source(s) of any other income you have.

For what it's worth, my current income is the highest it has ever been in my seventy-six years. But for 2024 I paid zero state or federal income taxes, because most of the money is from tax-free accounts of some kind, and the rest is below the minimum either the feds or my state care about.

Sometimes there are real advantages to being relatively poor.