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Basic Inflation Calculations
The Inflation Calculator computes purchasing power changes across time periods using CPI data. Here are common calculation examples:
/* How much is $100 from 1990 worth today? */
Base year: 1990
Target year: 2024
Amount: $100.00
CPI 1990: 130.7
CPI 2024: 314.2
Calculation: $100 × (314.2 / 130.7) = $240.40
Result: $100 in 1990 has the same purchasing power as $240.40 in 2024
Inflation over 34 years: 140.4%
Average annual inflation: 2.7%
/* How much was $1,000 in 2000 worth in today's dollars? */
Amount: $1,000
From year: 2000
To year: 2024
CPI 2000: 172.2
CPI 2024: 314.2
Result: $1,000 × (314.2 / 172.2) = $1,824.62
/* What would $50,000 salary in 2010 be worth today? */
Amount: $50,000
From year: 2010
To year: 2024
CPI 2010: 218.1
CPI 2024: 314.2
Inflation-adjusted: $50,000 × (314.2 / 218.1) = $72,031
Meaning: A $50,000 salary in 2010 required $72,031 in 2024 to maintain the same purchasing powerSalary and Wage Analysis
Inflation adjustment reveals whether wages are keeping pace with the cost of living:
/* Real wage analysis */
Employee salary history:
2015: $65,000
2020: $72,000 (+10.8% nominal increase)
2024: $78,000 (+8.3% nominal increase from 2020)
Inflation-adjusted values (in 2024 dollars):
2015: $65,000 × (314.2 / 237.0) = $86,130
2020: $72,000 × (314.2 / 258.8) = $87,380
2024: $78,000 (current)
/* Real wage change */
2015 to 2024:
Nominal increase: +$13,000 (+20%)
Real change: -$8,130 (-9.4%)
→ Employee's purchasing power DECREASED by 9.4%
2020 to 2024:
Nominal increase: +$6,000 (+8.3%)
CPI increase: +21.4% (2020-2024 high inflation period)
Real change: -$9,380 (-10.7%)
→ Significant real pay cut during high inflation period
/* Salary negotiation context */
To maintain 2015 purchasing power in 2024:
Required salary: $86,130
Current salary: $78,000
Gap: $8,130 (10.4% raise needed just to break even)Investment Return Analysis
Inflation-adjusted returns reveal the true growth of investments:
/* Real vs nominal investment returns */
Investment: $10,000 in S&P 500 index fund
Period: 2010 to 2024 (14 years)
Nominal performance:
2010 value: $10,000
2024 value: $52,400 (424% total return, ~11.5% annual)
Inflation adjustment:
CPI 2010: 218.1
CPI 2024: 314.2
Inflation: 44.1% over 14 years
Real (inflation-adjusted) performance:
Nominal return: 424%
Inflation: 44.1%
Real return: 263% (still excellent!)
Real annual: ~9.5%
/* Savings account comparison */
Savings account: 0.5% annual interest (2010-2024)
Nominal value after 14 years: $10,724
Inflation-adjusted value: $7,441
Real return: -25.6% ← Lost purchasing power!
/* Rule of 72 — inflation impact */
At 3% inflation, purchasing power halves in: 72/3 = 24 years
At 7% inflation, purchasing power halves in: 72/7 = 10 years
At 2% inflation, purchasing power halves in: 72/2 = 36 yearsHistorical Price Comparisons
Convert historical prices to today's dollars for meaningful comparisons:
/* Famous historical prices in 2024 dollars */
Item Year Original 2024 Equivalent
------------------ ---- --------- ---------------
Ford Model T 1908 $825 $27,400
Average US house 1950 $7,354 $93,200
Gallon of gas 1970 $0.36 $2.84
McDonald's Big Mac 1968 $0.49 $4.30
Average US salary 1960 $4,743 $49,200
Harvard tuition 1980 $6,000 $22,400
iPhone (original) 2007 $499 $742
/* Calculation example: 1950 house */
CPI 1950: 24.1
CPI 2024: 314.2
$7,354 × (314.2 / 24.1) = $95,800
/* What $1 could buy in different decades */
$1 in 1950 = $13.03 in 2024
$1 in 1970 = $7.89 in 2024
$1 in 1980 = $3.73 in 2024
$1 in 1990 = $2.40 in 2024
$1 in 2000 = $1.82 in 2024
$1 in 2010 = $1.44 in 2024
$1 in 2020 = $1.21 in 2024Retirement Planning with Inflation
Inflation significantly impacts how much money is needed for retirement:
/* Retirement nest egg calculation */
Current age: 35
Retirement age: 65
Years to retirement: 30
Current expenses: $60,000/year
Expected inflation: 3% per year
/* How much will $60,000/year cost at retirement? */
Future value = $60,000 × (1 + 0.03)^30
= $60,000 × 2.427
= $145,620/year needed at retirement
/* Nest egg needed (4% withdrawal rule) */
$145,620 / 0.04 = $3,640,500 needed at retirement
/* Without inflation adjustment (common mistake) */
$60,000 / 0.04 = $1,500,000 — severely underestimates!
/* Inflation impact on fixed income */
Pension: $3,000/month starting 2024
After 20 years at 3% inflation:
Nominal: still $3,000/month
Real purchasing power: $3,000 / (1.03^20) = $1,661/month
→ Pension lost 44.6% of its purchasing power
/* Social Security COLA (Cost of Living Adjustment) */
/* SS benefits are adjusted annually for CPI-W inflation */
/* This protects against inflation erosion */
/* Private pensions often have no COLA — plan accordingly */