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 St. Louis County, MO vs Lake 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.

Does WatchPennies require an account for comparisons?

No. County comparisons are available without creating an account.

St. Louis County, MO vs Lake County, IL: Cost of Living Difference

Is it cheaper?

St. Louis County, MO is cheaper than Lake County, IL.

Moving to Lake County, IL is estimated to cost $13,352 more per year.

Cheaper County

St. Louis County, MOSpend $13,352 more per year.

Salary needed

$50,000 in St. Louis County, MO is about $63,830 in Lake County, IL.

Biggest drivers

Housing increases by $5,509 per year. Food saves $92 per year.

Housing: $5,509 higher in Lake County, IL

Taxes: $4,585 higher in Lake County, IL

Childcare: about the same in both counties

Healthcare: $64 higher in Lake County, IL

Food: $92 lower in Lake County, IL

Transport: $1,606 higher in Lake County, IL

St. Louis County, MO→Lake County, IL

Equivalent salary in Lake County, IL

$63,830

+27.66% higher

Current salary: $50,000

Household: 1 adult · 0 children

Median Income in St. Louis County, MO: $108,392

Median Income in Lake County, IL: $132,828

Living Index in St. Louis County, MO 44.53%

Living Index in Lake County, IL 46.39%

This estimate matches your purchasing power (equivalent salary) when moving from St. Louis County, MO to Lake 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 St. Louis County, MO to Lake County, IL is estimated to cost $13,352 more per year. To maintain similar purchasing power, a $50,000 salary in St. Louis County, MO would need to be about $63,830 in Lake County, IL. The biggest increase is housing, followed by taxes.

This is a 27.66% increase in modeled annual costs. Housing is $5,509 per year higher (44.69%); Taxes is $4,585 per year higher (49.78%).

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 Lake County, IL.

Biggest Cost

Largest annual cost increase when moving to Lake County, IL

Annual Increase:

$5,509 per year

HOUSING has the largest annual increase when moving to Lake County, IL.

Biggest Savings

Largest annual savings when moving to Lake County, IL

Annual Savings:

$92 per year

FOOD has the largest annual savings when moving to Lake County, IL.

Breakdown of price percentages per category.

Numbers are average costs per section.

Category	Difference
Housing	44.69% higher
St. Louis County, MO Lake County, IL Average Cost $12328.00 $17837.00 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	-1.94% lower
St. Louis County, MO Lake County, IL Average Cost $4731.00 $4639.00 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	13.71% higher
St. Louis County, MO Lake County, IL Average Cost $11710.00 $13316.00 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	1.28% higher
St. Louis County, MO Lake County, IL Average Cost $4996.00 $5060.00 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	31.76% higher
St. Louis County, MO Lake County, IL Average Cost $5296.00 $6978.00 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
St. Louis County, MO Lake 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	49.78% higher
St. Louis County, MO Lake County, IL Average Cost $9210.00 $13795.00 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 Lake County, IL, modeled annual costs are $61,624 compared with $48,272 in St. Louis County, MO.

Overall, annual costs are higher in Lake County, IL. The category breakdown above shows whether housing, taxes, transportation, healthcare, food, childcare, or other necessities are driving the increase.

In this case Lake County, IL and St. Louis County, MO are both metropolitan locations.

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