There are actually two separate ratios to consider:
- Housing to income ratio:
[Y]our future monthly housing expense, including principal, interest, taxes, insurance, and any housing association or condominium fees
- Debt to income ratio
Total your monthly debt: Include minimum credit card payments, auto and student loans, consumer loans, and other financial obligations including child support and alimony. Do not include your current housing payment, unless you own your home and will keep that property.
Add in your estimated future housing expense, including principal, interest, taxes, insurance, and any housing association or condominium fees
(Quotations from Wells Fargo "How to Calculate Your Ratios" page)
The housing to income ratio should be under 28% or so. Debt to income ratio includes housing plus your other debts, and should really be under 36% or so; 43% is getting into the higher interest rate products that can be expensive.
"Insurance" above means home insurances - including flood or other insurances taken out for your home - but not health or car insurance.