The formula, first
Daily rate = (monthly rent × 12) ÷ 365
Everything else comes from that one line. It's the math you use to check move-in specials prices.
- Daily rate × days in the lease = gross lease cost
- Daily rate × free days = concession value
- (Gross − concession) ÷ lease months = effective monthly rent
Step one is always the day count
Concessions get quoted in weeks or in months. Weeks are a day count, so count the days first. A month free is one month of rent, whatever month it is.
| Quoted as | Days free |
|---|---|
| Four weeks free | 28 |
| Six weeks free | 42 |
| Eight weeks free | 56 |
| One month free | No day count: one month of rent, any month |
| Two months free | No day count: two months of rent |
“Six weeks free” and “a month and a half free” differ by about 3.6 days. At a $50 daily rate, that's $180. Plenty to decide between two close offers.
Six weeks free, step by step
$1,500 rent, 12 month lease, six weeks free.
- Daily rate: (1,500 × 12) ÷ 365 = $49.32
- Lease days: 365
- Gross lease cost: 49.32 × 365 = $18,000
- Free days: 42
- Concession value: 49.32 × 42 = $2,071
- Net lease cost: 18,000 − 2,071 = $15,929
- Effective monthly: 15,929 ÷ 12 = $1,327
The sign says $1,500. You average $1,327. That's the number to use when you compare offers. See net effective rent for the full definition.
Don't average the free weeks into months
“Six weeks free is about a month and a half” feels close enough, and it's wrong enough to rank two offers backwards. Do the days. A month free is the easy one: it is one month of rent, so only weeks and days need this math.
What the effective rent does not cover
Fees. Amenity, parking, package, valet trash, pest, pet rent, split utility bills (RUBS), and bulk internet come every month, and no concession touches them. Add them on top.
The clawback. If breaking early means paying back the free rent, you only get that effective rent by finishing the lease. Read the concession addendum.
Renewal. Concessions apply to year one. In month thirteen, the rent goes back toward market.
Our move-in specials page covers all three in more detail.
Longer terms and partial months
Two things come up a lot.
Terms other than 12 months. A 15 month lease has roughly 456 days. Use the real lease length in step one. The daily rate stays the same.
Prorated first month. If you move in partway through a month, the first month is prorated at the daily rate. It's the same number doing a different job, so check that the property figures it the way you do.
A month free is one month of rent, in any month
Rent is a monthly price. So a free February and a free July take off the same amount: one month of rent. At $1,825 rent, either one is worth $1,825. Don't turn a month free into days.
Days matter for weeks. At $1,825 rent the daily rate is $60. Four weeks free (28 days) is worth $1,680, which is $145 less than a month free. Six weeks free (42 days) is worth $2,520.
Ask the office: "Is the special a month of rent or a set number of days?" Then price it the right way.
Where this gets used
Use it any time two offers differ on lease length or on how they word the concession. Convert both, add each building's community fees, and then you just subtract one from the other.
Rather skip the arithmetic? Our net effective rent calculator will do the conversion for you.