raw cost for a below-poverty annual subsidy of $12.5k to all adults in the United States:
209,128,094(&) * 12,500 = 2.6 trillion USD/year
That's equal to about 66% of the 2015 federal budget or 15% of 2015 GDP.
Would that make it affordable or unaffordable?
Notes:
Every time basic income comes up, the one thing persistently avoided is running the budget and taxation numbers needed to support it (and there are endless excuses raised for why that discussion is avoided).
$2.6 trillion (basic income) + $600 billion (military) + $1.2 trillion (SS) + $1 trillion (M/M) = $5.4 trillion, and that's before you get into all the other costs of government. Throw on another $400 billion in other mandatory spending costs, and another couple hundred billion in other discretionary spending items.
$6 trillion is the minimum out of that, just for the Federal Government.
Now throw in $3 trillion for local and state.
$9 trillion in total government costs out of an $18 trillion economy. Pretty obvious what would happen to that system. And it's why nobody ever wants to discuss actual numbers.
I do. I want to talk about actual numbers because I think it'll be interesting to work out what might or might not be affordable. But I get rather frustrated that people either provide no numbers or do what you've just done and multiply the basic income amount by the total number of people and go no further.
You're making the assumption that everyone gets $12.5k more post-tax. That's not what many people would propose. There's also a reduction in the number of benefits and other programs that need to be funded (in the UK, anything above £4000 would eliminate the need for job-seekers allowance and several other benefits). SS is $1.2T, but some portion of that would be covered by BI.
The money also doesn't evaporate, one of the arguments in favour of large scale wealth redistribution like this is the people you distribute it to are the ones who are most likely to spend it.
It's an extremely complex issue, and both those saying "everything would be wonderful" and "X * Y = $$$ is too much" are doing it a disservice.
That's the raw cost for providing a post-tax increase of 12.5k for all adults.