Lake Forest, IL vs Oak Brook, IL: Cost of Living

Which city costs less?

Oak Brook, IL has a modeled overall cost index 1.9% lower than Lake Forest, IL.

Lake Forest, IL · modeled 2BR rent: $2,670 / month
Oak Brook, IL · modeled 2BR rent: $2,450 / month

These are saved estimates, not current rental listings. Some cities use adjusted regional data. Your household budget can differ from the overall index. Sources and assumptions

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Cost of Living Comparison 2026

Compare Lake Forest, IL and Oak Brook, IL using saved regional data and explicit budgeting assumptions. Rent estimates are not live listings. Change the salary below, then check the source notes before applying a result to your household.

Saved regional estimates · Sources and assumptions

Current salary in Lake Forest, IL

Numbers update automatically as you type

Estimated savings: $122/month in Oak Brook, IL

$150,000 in your current city has a modeled equivalent of $148,530 in Oak Brook, IL

Regional cost estimates: Lake Forest, IL uses Chicago, IL. Oak Brook, IL uses Chicago, IL. Available city ZIP rent estimates are shown separately.

Overall Cost

↓ 1.9%

Less expensive

Monthly Impact

$122

Savings

Annual Impact

$1.5K

Per year

Assumes 60% of current gross income goes to living costs. The headline uses the category budget below; taxes, moving costs and savings goals are excluded.

Lake Forest, IL

Population:19K

Cost Index:

96.2

100 = national average

Typical Home:$1.11M

Oak Brook, IL

Population:8K

Cost Index:

94.4

100 = national average

Typical Home:$1.15M

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Lake Forest, IL

The Prairie State

19K

Population

State Tax

Yes

Located in Illinois, this city has a population of 19K residents.

Oak Brook, IL

The Prairie State

Population

State Tax

Yes

Located in Illinois, this city has a population of 8K residents.

Cost Breakdown by Category

Estimated monthly spending: Lake Forest, IL vs Oak Brook, IL

Assumes 60% of your current gross income is spent on these categories. The headline and totals use this same budget. Rent estimates below are separate reference data. Rounded amounts may differ by $1.

Category	Lake Forest, IL	Oak Brook, IL	Difference	Change
Housing	$2,444/mo	$2,398/mo	↓ $46.07less	1.9%
Other	$1,557/mo	$1,527/mo	↓ $29.34less	1.9%
Transportation	$1,488/mo	$1,460/mo	↓ $28.04less	1.9%
Groceries	$966/mo	$957/mo	↓ $9.15less	0.9%
Healthcare	$558/mo	$553/mo	↓ $5.29less	0.9%
All Utilities	$487/mo	$483/mo	↓ $4.61less	0.9%

Housing

↓ 1.9%

Lake Forest, IL

$2,444

Oak Brook, IL

$2,398

Difference

$46.07

less

Other

↓ 1.9%

Lake Forest, IL

$1,557

Oak Brook, IL

$1,527

Difference

$29.34

less

Transportation

↓ 1.9%

Lake Forest, IL

$1,488

Oak Brook, IL

$1,460

Difference

$28.04

less

Groceries

↓ 0.9%

Lake Forest, IL

$966

Oak Brook, IL

$957

Difference

$9.15

less

Healthcare

↓ 0.9%

Lake Forest, IL

$558

Oak Brook, IL

$553

Difference

$5.29

less

All Utilities

↓ 0.9%

Lake Forest, IL

$487

Oak Brook, IL

$483

Difference

$4.61

less

🏠Rent Comparison

Studio

From$2,220

To$2,040

↓ $180

1 Bed

From$2,370

To$2,170

↓ $200

2 Bed

From$2,670

To$2,450

↓ $220

3 Bed

From$3,440

To$3,160

↓ $280

Lake Forest, ILZIP-level data

1BR range: $2,370–$2,370/mo

Oak Brook, ILZIP-level data

1BR range: $2,170–$2,170/mo

💡 Note: HUD Fair Market Rents estimate 40th-percentile gross rents, including most tenant-paid utilities. City ZIP summaries are medians of those estimates, not market median rents. Actual prices vary by neighborhood, amenities, and condition. Source: HUD Small Area Fair Market Rents FY2026.

$7,500

Monthly in Lake Forest, IL

$7,378

Monthly in Oak Brook, IL

$122

Difference

Home Values

Lake Forest

Oak Brook

$1.11M

Median Value

$1.15M

↑ +9.4%

YoY Change

↑ +8.5%

↑ +52.8%

5-Year Change

↑ +37.9%

Homes in Oak Brook are 4% more expensive than Lake Forest

Calculate payment - Lake Forest Calculate payment - Oak Brook

Source: Zillow Home Value Index (ZHVI), January 2026

Tax Comparison

Annual tax burden comparison at $150.0K salary

Tax Savings

→ $0

Same taxes

Monthly Difference

Same take-home

Effective Rate Diff

0.0%

Rate difference

Lake Forest, IL

Federal Income Tax

Effective: 18.9%

$25.5K

Illinois State Tax

Effective: 5.0%

$7.4K

FICA Taxes

Social Security + Medicare

$11.5K

Total Taxes

Effective: 29.6%

$44.4K

Take-Home Pay

$8,797/month

$105.6K

Oak Brook, IL

Federal Income Tax

Effective: 18.9%

$25.5K

Illinois State Tax

Effective: 5.0%

$7.4K

FICA Taxes

Social Security + Medicare

$11.5K

Total Taxes

Effective: 29.6%

$44.4K

Take-Home Pay

$8,797/month

$105.6K

Additional Tax Information

Lake Forest, IL Tax Rates

Sales Tax:8.8%

Property Tax:2.2%

Oak Brook, IL Tax Rates

Sales Tax:8.8%

Property Tax:2.2%

💡 Note: Tax calculations are estimates based on 2024/2025 tax brackets for single filers with standard deduction. Actual taxes may vary based on filing status, deductions, credits, and local variations.

Environment

Lake Forest

Oak Brook

54 Moderate

Air Quality

54 Moderate

35.8%

Good Air Days

35.8%

100 Very High

Climate Risk

100 Very High

🌊🌡🫨

Top Hazards

🌊🌡🫨

▲+3.2°F

2050 Outlook

▲+3.2°F

18 days

Heat Days >95°F

18 days

▲+3.2°F

2050 Outlook

▲+3.2°F

18 days

Heat Days >95°F

18 days

Before moving from Lake Forest, IL to Oak Brook, IL

Use this comparison to shortlist a move, then check the costs that depend on your household.

Compare actual homes. Get current quotes in Oak Brook, IL for the same bedroom count and included utilities as your home in Lake Forest, IL. Add parking, deposits, insurance and any overlapping leases. The rent estimates above are a starting point, not available listings.
Confirm your income. Check your expected pay with your employer, including any location adjustment. Use “Different salary at destination?” above to compare two incomes. The budget model excludes taxes and one-time moving costs; it is not a take-home-pay calculation.
Price your daily routine. Check the commute from a specific address to work, school or childcare. Add household expenses missing from this model, such as childcare, debt payments and medical needs. Verify local services before signing a lease.
Plan the transition. Get moving quotes and budget for travel, setup costs and time off. Open your Lake Forest to Oak Brook moving checklist to organize the tasks and timing.

Still choosing a destination? Explore cities similar to Oak Brook, IL by cost, housing, population and region.

Frequently Asked Questions: Lake Forest, IL vs Oak Brook, IL

How do the cost estimates for Lake Forest, IL and Oak Brook, IL compare?

Oak Brook, IL has a modeled overall cost index 1.9% lower than Lake Forest, IL. This is a broad model comparison, not a survey of today's prices or a forecast of your household spending. Some cities use adjusted regional fallback data.

What does the equivalent salary mean?

At a $150,000 salary in Lake Forest, IL, the model estimates $148,530 in Oak Brook, IL. It allocates 60% of gross income to the origin city’s category budget and applies each destination category’s relative cost. The equivalent salary adds the total category difference to your income. The monthly difference is the same category difference divided by 12; it is not take-home pay or guaranteed savings. Household size, childcare and your actual lease are not inputs to this calculation.

What rent estimates are available for Lake Forest, IL and Oak Brook, IL?

The modeled two-bedroom rents are $2,670/month in Lake Forest, IL and $2,450/month in Oak Brook, IL. Where available, the source is a city median of HUD FY2026 ZIP-level estimates; otherwise a saved metro table is used. City adjustments may also apply. These are not asking rents or available listings. Compare actual properties with the same bedroom count and included utilities.

How should I use this comparison before moving?

Use it to shortlist locations, then replace modeled costs with a current housing quote, employer-confirmed income, commute costs, insurance and your household's other expenses. Add one-time moving costs separately. Source years differ and the saved datasets are not a live price feed. Read the methodology for the formulas and fallback rules.