People type this into search every day: rent increase calculator.
The usual answer is “look at the new monthly rent.” That misses the part that hurts, which is how many months you will pay the new number.
This page uses the calculator defaults as a labeled example. It is not a forecast of your landlord, and it is not personalized financial advice. Notice rules and rent caps depend on the lease and the place you live. I am not going to invent a national notice period.
The extra cost is a subtraction, then a multiply
The rent increase impact calculator uses:
(new rent − current rent) × months
The assumptions say other housing costs stay unchanged, and the new rent applies for every entered month. Utilities, parking, and pet rent are outside this line unless you already folded them into the two rent figures.
Here are the published defaults:
- current monthly rent: $1,500
- new monthly rent: $1,625
- months at new rent: 12
Monthly change: 1625 − 1500 = $125.00
Percentage change: 125 ÷ 1500 = 8.3%
Added over 12 months: 125 × 12 = $1,500.00
Calculator result
Rent increase impact
- Current monthly rent
- $1,500.00
- New monthly rent
- $1,625.00
- Months at new rent
- 12 months
$1,500.00
added over the period
- Monthly change
- $125.00
- Percentage change
- 8.3%
The old year is 1500 × 12 = $18,000.00. The new year is 1625 × 12 = $19,500.00. The $1,500.00 gap is one extra old month, spread across the year.
Fig 1 · 1/2
One year of rent
Calculator defaults. $1,500 now, $1,625 next.
Cash spending
Old year
$18,000
New year
$19,500
Twelve months at $1,500 is $18,000.
Twelve months at $1,625 is $19,500. The gap is $1,500.
Fig 2 · 1/2
The new $1,625 month
Same $125 increase on a $1,500 rent
Old rent
$1,500
Increase
$125
The old $1,500 is still 92.3% of the new month.
The $125 increase is 7.7% of $1,625, and 8.3% of the old rent.
$125 a month is easy to shrug off on a renewal email. $1,500.00 over the lease is a vacation, or most of a security deposit, sitting in someone else’s account.
The Census figure is not this example
The Census Bureau’s January 2026 housing-costs note used the 2020–2024 American Community Survey 5-year estimates. National median gross rent (rent plus utilities) was $1,413, up $100 from the 2015–2019 period after inflation adjustment. That $1,413 is a five-year period estimate for renter-occupied units paying cash rent. It is not the $1,500 default on this calculator, and it is not the rent on your lease.
Gross rent in ACS includes utilities. The calculator fields are contract rent unless you add those bills yourself.
The Congressional Research Service Housing Cost Burdens in 2024 still uses the HUD line: housing is a cost burden above 30% of income, and a severe burden above 50%. Nearly half of renter households, 49.4%, were cost burdened in that 2024 ACS read. I already walked the 30% math in How much rent can I afford?.
The same $125 lasts as long as you stay
The months field is the whole question. Keep $1,500 to $1,625. Change only the stay.
- 12 months: $1,500.00 added
- 24 months: $3,000.00 added
- 36 months: $4,500.00 added
Old three-year rent: 1500 × 36 = $54,000.00
New three-year rent: 1625 × 36 = $58,500.00
Calculator result
Rent increase impact
- Months at new rent
- 36 months
$4,500.00
added over the period
- Monthly change
- $125.00
- Percentage change
- 8.3%
Fig 3 · 1/2
If the new rent holds
$1,500 versus $1,625, grouped by years stayed
- Old rent path
- Added by the increase
| Category | Old rent path | Added by the increase |
|---|---|---|
| 1 year | $18k | $1.5k |
| 2 years | $36k | $3.0k |
| 3 years | $54k | $4.5k |
The first year adds $1,500 on top of $18,000.
Stay three years at the new rent and the extra is $4,500.
This stacked figure assumes the $1,625 does not rise again. A second increase would add another layer. I am not going to invent that second letter.
Small percentages are still real dollars
Hold $1,500 and 12 months. Change only the size of the raise.
- 5%: new rent $1,575. Extra $75.00 a month, $900.00 over the year.
- 8.3% (the default): new rent $1,625. Extra $125.00 a month, $1,500.00 over the year.
- 10%: new rent $1,650. Extra $150.00 a month, $1,800.00 over the year.
- 15%: new rent $1,725. Extra $225.00 a month, $2,700.00 over the year.
Fig 4 · 1/1
Four raises on a $1,500 rent
Each bar is 12 months at the new rent
- Added over 12 months
| Category | Added over 12 months |
|---|---|
| 5% | $900 |
| 8.3% | $1.5k |
| 10% | $1.8k |
| 15% | $2.7k |
A 5% raise adds $900 over the year.
The default 8.3% raise adds $1,500. A 15% raise adds $2,700.
A 5% letter looks small on the page. $900.00 is 0.6 of one old month, paid $75 at a time.
Check the new rent against the 30% line
The rent affordability calculator takes monthly take-home pay, then subtracts debts, other essentials, and a savings target. It also computes 30% of the income you entered. The published result is the lower of those two figures.
Affordability defaults, the same ones as the rent post:
- take-home income: $4,200
- debt payments: $350
- other essentials: $1,200
- savings target: $600
Cash-flow ceiling: 4200 − 350 − 1200 − 600 = $2,050
30% reference: 4200 × 0.3 = $1,260
Conservative rent: $1,260
Calculator result
Rent affordability
- Monthly take-home income
- $4,200.00
- Monthly debt payments
- $350.00
- Other essential spending
- $1,200.00
- Monthly savings target
- $600.00
$1,260.00
conservative monthly rent
- Cash-flow ceiling
- $2,050.00
- 30% reference
- $1,260.00
- Amount left after suggested rent
- $1,390.00
The old $1,500 is 35.7% of that $4,200. The new $1,625 is 38.7%. Both sit above the $1,260 conservative line. After debts and essentials, $1,625 leaves $1,025.00. After the $600 savings target too, $425.00.
The 30% line is a US housing-policy cutoff. CRS and HUD use it on pre-tax income and gross rent, including utilities. Here I applied it to the calculator’s take-home defaults so the two tools talk to each other. That is a labeled planning setup, not the federal statistic.
The leftover month shrinks by the same $125
The monthly budget planner subtracts housing, food, transport, and everything else from take-home pay.
Its defaults use $1,400 housing, not $1,500. I am going to swap housing to the two rents in this post so the leftover is about this increase.
Take-home $4,200. Food $650. Transport $350. Everything else $900.
- housing $1,500: leftover $800.00
- housing $1,625: leftover $675.00
The $125 raise took $125 of leftover. If the $600 savings target still has to come out of that $675.00, $75.00 remains.
That $75.00 is the month after this example increase, on these example bills. A second bill moving the other way can wipe it.
Fig 5 · 1/2
Leftover after the raise
$4,200 take-home, food $650, transport $350, other $900
Left this month
Old rent
$800
New rent
$675
At $1,500 rent the leftover is $800.
At $1,625 rent the leftover is $675.
Other bills move when rent moves
The emergency fund target is essential housing plus living costs plus required debt, times the months you want. The defaults use $1,500 housing and a $3,150 essential month. Six months is $18,900.
Swap housing to $1,625. The essential month becomes 1625 + 1300 + 350 = $3,275. Six months becomes $19,650. The raise added $750 to the cash target, 125 × 6.
If you split rent, the roommate rent split post is the next click. $125 extra on a two-person even split is $62.50 each, $750 each over 12 months. The lease still lists the full $1,625.
Should I rent or buy this house? prices five years of rent against a simplified ownership cost. The rent side of that tool is monthly rent × years × 12. A $1,625 rent for five years is $97,500. The $1,500 rent is $90,000. The $7,500 gap is this same $125, held for 60 months. That comparison still excludes home-price change, the same way the rent-vs-buy page does.
What the notice is, and what it is not
The CFPB’s help for renters page is about paying rent and finding local assistance. It does not set a private-market raise cap.
HUD-assisted housing is a narrower case. HUD’s model lease and briefing materials tell owners to give a written rent-increase notice and a chance to discuss it. That is HUD’s program rule. It is not your city’s private-lease statute.
Read the renewal letter against the current lease. If the term has not ended, the old rent usually still applies unless the lease already allowed a mid-term change, or you agree. Month-to-month notice windows are state and local. I am not going to pick one and pretend it is national.
If the new number does not fit, the choices are negotiate, stay and recut the rest of the month, or move. Moving has its own cash, and it is not in this calculator.
Open the rent increase impact calculator with the two rents on the letter and the months you will actually stay. Then drop the new rent into the rent affordability calculator and the monthly budget planner before you sign.