B2 visa overstay or not?

[orso]

Hello,
My mom has 10 years tourist visa, she has been in the US in the last 3 years once for 5 months and once for 3 months.
She will be coming to visit me in 2018 Jan and will stay until July. In overall when I use time calculator it says it is 184-185 days if one looks to her entry day and leaving day on her plane tickets.However, we are planning to go Canada in April for one week of vacation, about 7 days and return back to US and then she will leave back home. After she stays 3 months here can we go to Canada for a week and come back to US without any issues?
Does this situation can be considered as overstay or not? What kind of problems it can cause? Should I change her plane ticket?
Thank you
Orso

[immihelp]

She can stay in the US until the date on I-94 form.

That is usually maximum of 6 months.

Therefore, it would not be a good idea to have the plane ticket more than that. In fact, do couple of days less.

[orso]

She can stay in the US until the date on I-94 form.

That is usually maximum of 6 months.

Therefore, it would not be a good idea to have the plane ticket more than that. In fact, do couple of days less.

Thank you for your response.
How the things are changing when we go to Canada though? Then in the reentrance she will have a new stamp with a new date on it?
Can't she not stay 3 months US + 1 week Canada and then 3 months US. This will make her total stay less than six months aka 5 months, 28 days.