Real estate: how much to put down?
If a VETERAN zero, if you go USDA zero, FHA 3.5%, Conventional 20%. It depends on which type loan you can qualify for. Talk to a lender.
However much your lender tells you to. It will also depend on whether you are buying land (expect 20% down) or a house. Minimum down payment on a house is 0% if you are a vet or the house qualifies for a USDA loan. After that, FDHA has loans for 3.5% down while conventional loans will require 10% and up. After that its is up to you - just remember to factor in closing costs which can run 5 - 6%,
Typically either whatever you have or as little as they'll allow. Requirement are as little as 3.5% on FHA but probably 20% on anything investor or 2nd home.
20% If you asked about the required down payment, sure the above answers have merit. You asked "how much to put down" which implies you are asking how much you should put down, not how much you must put down. If your lender requires a specific percentage, you already have your answer. So, my 20% suggestion is based on my recommendation...but sure, if you qualify, go with a lower one...we'll answer your questions about being underwater after the next downturn. Also...PMI... https://www.bankrate.com/finance/mortgages/the-basics-of-private-mortgage-insurance-pmi.aspx