How about a picture of your current panel?

How many amps is it?

An electrician can easily add a subpanel as long as your home line can support the extra power. This is what they did with our remodel. Not too expensive I might add.

Subpanels are common.

There is an electric forum here and they can help. I am not an electrician, but it looks like you couldn't be overloaded. You have a normal 200 amp service and you don't currently have even one 30, or 40 amp 220 volt draw.

I don't know if there are extender bars or something or if you could just replace the bars with the correct length ones, but it seems plausable to me. Ask over in electric. You could instead replace a couple of the standard size breakers with the compact breakers to make room for the new 220 breaker pair. I assume that you would need to run a new heavy gage cable to the oven, but it sounds like that would be very easy since the panel is presumably accessable from the inside as is the floor above.

Don't think you need a sub panel. Looks like you have plenty of space in your current panel!

I’m married to an electrician and it’s not how many twist outs you have leftover, it’s how many amps in each breaker that adds up to the panel. This panel is a 100 amp service and a 220 circuit would have to be dedicated to the double oven (same with stove, if electric, and the microwave (110 circuit), etc. If you are maxed out, then the electrician will have to install a new panel and service (additional 100 amp service is normal). It took my husband 2 days to replace our 100 amp Sub panel. It’s many hours of work.

Now your next picture should be one where you've removed the screws that mount the cover and taken the cover off. Then we'll have all the info.

It is best to install a new 200 amp panel for the additional load that is going to be needed. Rough estimate is about $3000 plus permit fees.

If you go down the route of replacing the panel, have a conversation with your electrician about what you'll need in the future. You don't want to spend $3000 today in order to upgrade to 200A service, and then spend another $4000 in five years to install a charger for your electric car.

Breakers are intended to protect the conductors beyond them. The main breaker in a service entry box protects the box and the service entry conductors. The actual load on each breaker, in concert with the probabilities of simultaneous specific loads on all the other breaker circuits, determines the load that the breaker box should be designed for.

In other words, demand factors (see NFPA 70 sec. 220 for example) have to be applied to the calculations for the box and various circuits. In other other words, a breaker box does not have to be rated at the sum of the rated values of the breakers connected to it. This does not mean that one can blithely fill a box with large breakers protecting multiple downstream breaker boxes without limit; the load and demand factor calculations have to be performed.

Kaseki is correct, there’s a math formula that goes into deciding how full a panel is, so the amps may add up to more than 100 assuming you won’t be turning everything on all at once. I would definitely be worried though if your House is prone to ghosts turning all the electricity on at once (joke). I think 3k is a bit high for another panel, it will be less if you live in a lower cost of labor area. As for the car charger, put it on a new service entirely and put that on a night rate and charge it cheaper in the dead of night. That’s what we do. Otherwise that electric car will add hundreds to your bill.