A common guideline is to spend no more than 28-30% of your income on rent. The classic rule uses gross (pre-tax) income, but this calculator applies your percentage to take-home (after-tax) pay for a more honest target. If your take-home is about $4,500/mo, that's roughly $1,260-$1,350. In expensive cities some people stretch to 35%, but that leaves less room for savings and emergencies.