3 times the rent "rule"

[George Pan]

Hello,

I just read the ultimate guide sticky post about screening and renting.

I have a question about tenant income.
They suggest that a tenant should have at least 3 times the rent in monthly (gross) income.
If we were to use an example of a 3 bedroom apartment for say $1,200 per month. So, each tenant is responsible for $400 each month. That means that each tenant should gross at least $1,200 per month or $14,400 per year!

I think that is cutting it a little too close?

What are your thoughts on that?

Which approach do you use when looking at income?