Rent keeps climbing. Here’s the math nobody explains.

If you’ve signed a lease in the last few years, you already know the feeling: the number on the renewal letter went up again, and your paycheck didn’t keep pace.

The short version

Rent is set by how many homes exist and how many people want them. For years the country built fewer homes than it needed, and the shortfall shows up in prices.

Why it hits first-time renters hardest

Landlords can raise rent most easily on new leases. Someone who has lived in the same apartment for five years is often paying less than the person who just moved in next door.

• New leases reset to whatever the market will bear.
• Moving costs, deposits and application fees stack on top.
• Entry-level jobs often pay the least in the cities with the most openings.

What to watch

Local zoning votes. They don’t make headlines, but they decide how many homes can be built near you, and that decides what you’ll pay.