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 Maricopa County, AZ vs St. Louis County, MO 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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Maricopa County, AZ vs St. Louis County, MO: Cost of Living Difference

Is it cheaper?

St. Louis County, MO is cheaper than Maricopa County, AZ.

Moving to St. Louis County, MO is estimated to save $9,186 per year.

Cheaper County

St. Louis County, MOSave about $9,186 per year.

Salary needed

$50,000 in Maricopa County, AZ is about $42,005 in St. Louis County, MO.

Biggest drivers

Food increases by $600 per year. Housing saves $6,147 per year.

Housing: $6,147 lower in St. Louis County, MO

Taxes: $1,671 lower in St. Louis County, MO

Childcare: about the same in both counties

Healthcare: $170 higher in St. Louis County, MO

Food: $600 higher in St. Louis County, MO

Transport: $416 lower in St. Louis County, MO

Maricopa County, AZ→St. Louis County, MO

Equivalent salary in St. Louis County, MO

$42,005

-15.99% lower

Current salary: $50,000

Household: 1 adult · 0 children

Median Income in Maricopa County, AZ: $100,929

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

Living Index in Maricopa County, AZ 56.93%

Living Index in St. Louis County, MO 44.53%

This estimate matches your purchasing power (equivalent salary) when moving from Maricopa County, AZ to St. Louis County, MO.

* 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 Maricopa County, AZ to St. Louis County, MO is estimated to save $9,186 per year. A $50,000 salary in Maricopa County, AZ would have similar purchasing power to about $42,005 in St. Louis County, MO. The largest savings come from housing and other costs.

This is a 15.99% decrease in modeled annual costs. Housing is $6,147 per year lower (33.27%); Other Costs is $1,722 per year lower (24.54%).

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 St. Louis County, MO.

Biggest Cost

Largest annual cost increase when moving to St. Louis County, MO

Annual Increase:

$600 per year

FOOD has the largest annual increase when moving to St. Louis County, MO.

Biggest Savings

Largest annual savings when moving to St. Louis County, MO

Annual Savings:

$6,147 per year

HOUSING has the largest annual savings when moving to St. Louis County, MO.

Breakdown of price percentages per category.

Numbers are average costs per section.

Category	Difference
Housing	-33.27% lower
Maricopa County, AZ St. Louis County, MO Average Cost $18475.00 $12328.00 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	14.52% higher
Maricopa County, AZ St. Louis County, MO Average Cost $4131.00 $4731.00 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	-3.43% lower
Maricopa County, AZ St. Louis County, MO Average Cost $12126.00 $11710.00 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	3.52% higher
Maricopa County, AZ St. Louis County, MO Average Cost $4826.00 $4996.00 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	-24.54% lower
Maricopa County, AZ St. Louis County, MO Average Cost $7018.00 $5296.00 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
Maricopa County, AZ St. Louis County, MO 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	-15.36% lower
Maricopa County, AZ St. Louis County, MO Average Cost $10881.00 $9210.00 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 St. Louis County, MO, modeled annual costs are $48,272 compared with $57,458 in Maricopa County, AZ.

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

In this case St. Louis County, MO and Maricopa County, AZ are both metropolitan locations.

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