Gross rent vs net effective rent
Gross rent is the monthly rent written in your lease. Net effective rent is the average you pay per month once free months and other one-time concessions are spread across the whole lease. Listings often lead with the net number because it is lower. You will still write a check for the gross amount in most months.
The formula
Net effective rent = (gross rent × lease months − gross rent × free months − other concessions) ÷ lease months.
Working backwards from an advertised net price: gross rent = (net effective × lease months + other concessions) ÷ (lease months − free months). Use the calculator’s “Advertised net effective” mode for this.
Worked examples
| Listing | Gross rent | Net effective | Paid over lease |
|---|---|---|---|
| $4,000, 12 months, 1 month free | $4,000.00 | $3,666.67 | $44,000 |
| “$3,500 net,” 13 months, 1 month free | $3,791.67 | $3,500.00 | $45,500 |
In the first case you save $4,000 over the year, but 11 of 12 checks are $4,000. If the landlord offers a renewal at the same gross rent with a 3% increase, the new rent is $4,120: $453.33 more per month than the $3,666.67 you thought you were paying. In the second, the $3,500 headline hides a real monthly rent of about $3,792.
What to check before you sign
- Which rent the lease states. Your lease should show the gross rent and describe the concession. Make sure the free month is written into the lease, with the month it applies to.
- What the renewal is based on. Ask in writing whether a renewal offer would start from the gross rent. For market-rate apartments, the increase is usually a negotiation; see negotiating a market-rate renewal.
- Which rent sets the income test. The 40x income rule is a landlord practice, not a law. At 40x, the gap between $4,000 gross and $3,666.67 net is $13,333 of required yearly income. Read more in the NYC 40x rent rule.
- Every fee. Under the FARE Act, the city’s Department of Consumer and Worker Protection says listings must clearly disclose all fees a tenant must pay, and you must sign an itemized fee disclosure before the lease.
Edge cases
- Half a free month (two weeks) works the same way: enter 0.5.
- A landlord credit toward a move-in cost counts as an “other concession.”
- If free months equal or exceed the lease term, the math breaks down; the calculator stops you.
- The calculator ignores the time value of money. A free first month is worth slightly more to you than a free last month.
Next steps
Check whether the gross rent fits your budget with the rent affordability calculator, and total your upfront cash with the NYC move-in cost calculator. For a longer explanation, read net effective rent vs gross rent.