The answer first
$1,083 against $1,146. The 15 month lease wins by $63 a month.
That's the answer for the case below, worked out the same way our true monthly cost page shows. The math is simple. Renewal is the part that can flip it.
The case
Same building, same floorplan, two offers at $1,250 headline rent.
| Offer A | Offer B | |
|---|---|---|
| Term | 15 months | 12 months |
| Concession | 2 months free | 1 month free |
| Daily rate | $41.10 | $41.10 |
| Lease days | About 456 | 365 |
| Free rent | 2 months of rent | 1 month of rent |
| Gross lease cost | $18,750 | $15,000 |
| Concession value | $2,500 | $1,250 |
| Net lease cost | $16,250 | $13,750 |
| Effective monthly | $1,083 | $1,146 |
A free month comes off as one full month of rent, so there's no day count to do here. The daily rate (monthly rent × 12 ÷ 365) comes in when an offer is quoted in weeks or days. See how effective rent works if you want the reasoning behind it.
Why the longer term wins here
Two months free takes $2,500 off. One month free takes $1,250 off. The extra free month is worth $1,250, whatever month it lands in. Spread it over three extra months and the bigger concession still cuts more off each month.
That's the general pattern: when the free rent grows faster than the term, the longer lease wins on effective rent.
It isn't a rule. Six weeks free on 15 months against one month free on 12? That one's much closer, and it can go the other way. Run both instead of guessing.
What the number does not include
The community fees. Identical in this case, since it's the same building. Across two different buildings, the gap in fees can be bigger than the $63, so add the community fees before you rank them.
The clawback. If you have to pay back the concession when you break early, offer A leaves you on the hook for 15 months instead of 12. Three extra months of that risk is a real cost if there's any chance you'll leave.
The renewal. This is the one that matters most.
Concessions apply to year one
On offer A, rent moves back toward market rate in month sixteen. On offer B, it happens in month thirteen. Ask what the unit renewed at last year and whether the concession repeats. If it doesn't, the jump at renewal can wipe out the $63 you saved in year one.
A longer lease moves your renewal season
Sign 15 months in March and the lease ends around June. Sign 12 months in March and it ends around March.
Dallas leasing is seasonal. Summer is the busiest stretch, and July concessions don't look like February ones. Where your renewal or next search lands on that calendar matters. Some renters pick 15 months for exactly that reason, not for the concession.
How to decide
- Turn both offers into effective monthly rent.
- Add each building’s community fees to get true monthly cost.
- Ask the clawback question on both.
- Ask what the unit renewed at last year on both.
- Ask yourself if you'll really stay 15 months.
If the answer to step 5 is yes, the longer term usually wins. Any doubt at all? Then the $63 isn't worth the risk.