$40K in Lafayette = $38,588 in Rockford
Your $40K salary in Lafayette (COL 85) has the same purchasing power as $38,588 in Rockford (COL 82). Rockford is cheaper — your money goes 4% further there.
Budget breakdown — $40K in both cities
What $40K actually buys you in each city after taxes and core expenses.
| Expense | Lafayette $40K | Rockford $40K (same salary) |
|---|---|---|
| Monthly take-home | $2,585 | $2,562 |
| 1BR rent | $1,100 | $1,050 |
| Groceries | $361 | $357 |
| Transport | $42 | $50 |
| Utilities | $208 | $158 |
| Internet | $58 | $58 |
| Left after essentials | $816/month | $889/month |
Frequently asked questions
What is $40K in Lafayette equivalent to in Rockford?
$40K in Lafayette (COL index 85) has the same purchasing power as $38,588 in Rockford (COL index 82). That's 4% less than your current salary.
If I move from Lafayette to Rockford keeping my $40K salary, will I be better off?
Yes. If you keep earning $40K after moving to Rockford, you'd have $73 more per month after core expenses — because Rockford is cheaper than Lafayette.
How is the salary equivalent calculated?
The equivalent salary is calculated by multiplying your current salary by the ratio of the two cities' overall cost of living indices: $40K × (82 ÷ 85) = $38,588. This adjusts for differences in housing, food, transport, and general cost of living.
Other salary amounts — Lafayette to Rockford
Equivalency uses overall COL index ratio. Take-home uses simplified federal/state brackets. Zillow · BLS · Numbeo · Q1 2026 · For general guidance only