Nothing is standard when you are comparing across North America. You really need to find out what is common in your area as that’s all that matters.

I live in Vancouver BC Canada and the cost is $300+ per square foot, friends who just built paid $475/sq foot.

Online calculators will often take your money for garbage output.

Check in with local custom builders. Visit custom spec homes for sale (not tract) and ask.

A quick hack: find a local new custom spec for sale on zillow, subtract what they paid for the lot, multiply x 120% to get to today's general cost (for that level of complexity and finish). Repeat a few times for consistency.

Costs over time move up with little exception. While lumber has fallen significantly from its temporary peak, it is still significantly above early 2020 and likely will increase.

There is no standard as mentioned above.

We have a great builder, loved by everyone he's worked with, but even some of his estimates calculated from the building plans were way off. We are double on what was budgeted for cabinets, so instead of 5 figures we went into 6 figures. Front door twice as much. Electrical we went way over. Garage doors twice as much. Irrigation well four times as much. Etc.

I think some of it is because the area we are building in, had in the past been a cheaper area to build in, but due to many reasons the last few years, the demand and pricing have creeped up to match some metro areas in the northeast. I would guess that the estimated price per sq.ft has gone up roughly $70-100 since we bought the lot 2 years ago. We are able to deal with these extra expenses, but not something you really want to have happen. You have to put things in perspective too ... we used to live in CA and built a large guest house 10 years ago. Even the elevated cost/sq.ft we are paying now, in our new area, will be less than what we paid 10 years ago in CA!

The other cost you have now during covid, with the delay of getting materials, is having to come up with money/deposit for orders much earlier than you would have in the past. You have to do this or you won't have materials arrive in time to get the house built. For example some window orders are out 7 months, when normal lead times would have been 6 weeks. The bank hasn't changed their process to account for this, so we are the ones who have bankrolled all this extra cash that normally wasn't needed as early in the process. It is what it is, but definitely a roller coaster ride many of us didn't anticipate when life plans were set into motion a few years ago!

Bottom line, don't take on a custom home build unless you have the flexibility to handle similar, or worse, events.

Good luck!