$40K in Boise = $31,238 in Rockford

Your $40K salary in Boise (COL 105) has the same purchasing power as $31,238 in Rockford (COL 82). Rockford is cheaper — your money goes 22% further there.

$40K in Boise, ID
$2,535/mo take-home
Rent: $1,600/mo (63% of take-home)
Difficult
$31,238/yr in Rockford, IL
$2,001/mo take-home
Rent: $1,050/mo (52% of take-home)
Difficult

Budget breakdown — $40K in both cities

What $40K actually buys you in each city after taxes and core expenses.

Expense
Boise
$40K
Rockford
$40K (same salary)
Monthly take-home$2,535$2,562
1BR rent$1,600$1,050
Groceries$372$357
Transport$45$50
Utilities$145$158
Internet$60$58
Left after essentials$313/month$889/month
To match your Boise purchasing power in Rockford, you'd need to earn $31,238/year (22% less than $40K). At that salary, you'd have $328/mo left after essentials — vs $313/mo in Boise.

Frequently asked questions

What is $40K in Boise equivalent to in Rockford?

$40K in Boise (COL index 105) has the same purchasing power as $31,238 in Rockford (COL index 82). That's 22% less than your current salary.

If I move from Boise to Rockford keeping my $40K salary, will I be better off?

Yes. If you keep earning $40K after moving to Rockford, you'd have $576 more per month after core expenses — because Rockford is cheaper than Boise.

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 ÷ 105) = $31,238. This adjusts for differences in housing, food, transport, and general cost of living.

Other salary amounts — Boise to Rockford

$50K → $39,048$60K → $46,857$75K → $58,571$80K → $62,476$100K → $78,095$120K → $93,714$150K → $117,143
$40K in Rockford → BoiseMoving from Boise to RockfordBoise vs Rockford — full comparisonCan I afford Boise vs Rockford on $40K?

Equivalency uses overall COL index ratio. Take-home uses simplified federal/state brackets. Zillow · BLS · Numbeo · Q1 2026 · For general guidance only