What does WatchPennies calculate?

WatchPennies estimates cost of living by US county across housing, food, transportation, healthcare, childcare, other necessities, taxes, and income context.

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Can I compare two counties on WatchPennies?

Yes. WatchPennies lets you compare counties and adjust salary and family type to estimate relative cost differences.

What does the Contra Costa County, CA vs DuPage County, IL comparison show?

It compares estimated living costs by category, including housing, food, transportation, healthcare, childcare, other necessities, taxes, and income context.

Can I change the salary and family type?

Yes. The comparison calculator supports salary and family type inputs so you can model costs for different households.

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Contra Costa County, CA vs DuPage County, IL: Cost of Living Difference

Is it cheaper?

DuPage County, IL is cheaper than Contra Costa County, CA.

Moving to DuPage County, IL is estimated to save $10,053 per year.

Cheaper County

DuPage County, ILSave about $10,053 per year.

Salary needed

$50,000 in Contra Costa County, CA is about $43,370 in DuPage County, IL.

Biggest drivers

No measured category is higher in DuPage County, IL. Housing saves $3,019 per year.

Housing: $3,019 lower in DuPage County, IL

Taxes: $2,887 lower in DuPage County, IL

Childcare: about the same in both counties

Healthcare: $1,866 lower in DuPage County, IL

Food: $196 lower in DuPage County, IL

Transport: $1,087 lower in DuPage County, IL

Contra Costa County, CA→DuPage County, IL

Equivalent salary in DuPage County, IL

$43,370

-13.26% lower

Current salary: $50,000

Household: 1 adult · 0 children

Median Income in Contra Costa County, CA: $146,002

Median Income in DuPage County, IL: $136,376

Living Index in Contra Costa County, CA 51.94%

Living Index in DuPage County, IL 48.23%

This estimate matches your purchasing power (equivalent salary) when moving from Contra Costa County, CA to DuPage County, IL.

* Living index is estimated as (estimated total cost / area median income) * 100. A living index above 100% means modeled costs exceed median income.

Cost of Living Breakdown by Category

Summary

Moving from Contra Costa County, CA to DuPage County, IL is estimated to save $10,053 per year. A $50,000 salary in Contra Costa County, CA would have similar purchasing power to about $43,370 in DuPage County, IL. The largest savings come from housing and taxes.

This is a 13.26% decrease in modeled annual costs. Housing is $3,019 per year lower (12.97%); Taxes is $2,887 per year lower (15.94%).

Below we break down the annual categories behind the difference using Economic Policy Institute 2026 Family Budget data.

What changed the most?

The following cards show the annual category differences that most affect the move to DuPage County, IL.

Biggest Cost

Largest annual cost increase when moving to DuPage County, IL

Annual Increase:

No increase

No measured category is higher in DuPage County, IL.

Biggest Savings

Largest annual savings when moving to DuPage County, IL

Annual Savings:

$3,019 per year

HOUSING has the largest annual savings when moving to DuPage County, IL.

Breakdown of price percentages per category.

Numbers are average costs per section.

Category	Difference
Housing	-12.97% lower
Contra Costa County, CA DuPage County, IL Average Cost $23270.00 $20251.00 INFO: Housing costs are based on Department of Housing and Urban Development data. The estimate uses 40th percentile rent for privately owned rental units in each area. Studio apartments are paired with one-adult households, one-bedroom apartments with two-adult households, and two-bedroom apartments with households that have children.
Food	-3.94% lower
Contra Costa County, CA DuPage County, IL Average Cost $4973.00 $4777.00 INFO: Food costs are based on the U.S. Department of Agriculture's food plans. Numbers are normalized to each area using Feeding America and Meal Gap data. This estimate assumes most food is bought at local grocery stores and prepared at home.
Transport	-7.89% lower
Contra Costa County, CA DuPage County, IL Average Cost $13780.00 $12693.00 INFO: Transportation costs are a combination of auto ownership, auto use, and public transit. Data is collected from the Center for Neighborhood Technology (CNT).
Healthcare	-26.97% lower
Contra Costa County, CA DuPage County, IL Average Cost $6920.00 $5054.00 INFO: Healthcare expenses come from average insurance premiums and out-of-pocket costs. The estimate assumes families purchase the lowest-cost available insurance plan under the Affordable Care Act. Data comes from Kaiser Family Foundation and the U.S. Department of Health and Human Services (HHS).
Other Costs	-11.39% lower
Contra Costa County, CA DuPage County, IL Average Cost $8769.00 $7770.00 INFO: This cost is calculated through the average spending of categories deemed necessary by the Bureau of Labor Statistics Consumer Expenditure Survey. These include apparel, personal care, household supplies, reading materials, and school supplies.
Childcare	0.00% higher
Contra Costa County, CA DuPage County, IL Average Cost $0.00 $0.00 INFO: Childcare expenses are based on combined costs for center-based care and family-based care for 4-year-olds and school-aged children. For households with one child, the estimate assumes the child is 4 years old. For households with two children, the estimate assumes the second child is 8 years old.
Taxes	-15.94% lower
Contra Costa County, CA DuPage County, IL Average Cost $18115.00 $15228.00 INFO: Taxes are calculated from the National Bureau of Economic Research. The number weighs in personal income tax, state income tax, federal Social Security, and Medicare taxes.

In DuPage County, IL, modeled annual costs are $65,774 compared with $75,827 in Contra Costa County, CA.

Overall, annual costs are lower in DuPage County, IL. The category breakdown above shows where the move creates the most room in the budget.

In this case DuPage County, IL and Contra Costa County, CA are both metropolitan locations.

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