$40K in Springfield = $40,494 in Rockford
Your $40K salary in Springfield (COL 81) has the same purchasing power as $40,494 in Rockford (COL 82). Rockford is more expensive — you'd need 1% more to maintain the same lifestyle.
Budget breakdown — $40K in both cities
What $40K actually buys you in each city after taxes and core expenses.
| Expense | Springfield $40K | Rockford $40K (same salary) |
|---|---|---|
| Monthly take-home | $2,562 | $2,562 |
| 1BR rent | $1,000 | $1,050 |
| Groceries | $357 | $357 |
| Transport | $48 | $50 |
| Utilities | $155 | $158 |
| Internet | $58 | $58 |
| Left after essentials | $944/month | $889/month |
Frequently asked questions
What is $40K in Springfield equivalent to in Rockford?
$40K in Springfield (COL index 81) has the same purchasing power as $40,494 in Rockford (COL index 82). That's 1% more than your current salary.
If I move from Springfield to Rockford keeping my $40K salary, will I be better off?
Not necessarily. Core expenses in Rockford are higher, so on the same $40K salary you'd have $55 less per month. You'd need to earn $40,494 to maintain the same standard of living.
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 ÷ 81) = $40,494. This adjusts for differences in housing, food, transport, and general cost of living.
Other salary amounts — Springfield to Rockford
Equivalency uses overall COL index ratio. Take-home uses simplified federal/state brackets. Zillow · BLS · Numbeo · Q1 2026 · For general guidance only