Annual Inflation Rate
Expected annual rate of increase in prices over time. Used to project future costs and adjust indexed income/tax brackets. Typical range: 2-4% per year.
How it works
The inflation rate assumption determines how dollar amounts grow (or lose purchasing power) over time. This rate is applied annually to income sources, tax brackets, and expenses when inflation indexing is enabled. A 3% inflation rate means a $100,000 expense today will cost $103,000 next year, $106,090 in two years, etc.
1. Historical Inflation Baseline
Review historical inflation trends to establish a baseline. The Federal Reserve targets 2% long-term inflation. Actual rates vary: 1-2% in 2010s, 7-9% in early 2020s, then moderating back toward target.
Example: Last 10 years average: 2.5% | Last 50 years average: 3.8% | Long-term target: 2.0%2. Planning Horizon Consideration
Longer planning horizons (20-40 years) typically use conservative rates closer to long-term averages. Short-term planning (5-10 years) may reflect current economic conditions more heavily.
Conservative Approach = Long-term Historical Average (3-4%)
Example: 30-year retirement projection: Use 3.0% to avoid underestimating future costs3. Apply to Indexed Items
Inflation rate is applied to enabled items: tax brackets, wages, pensions, Social Security, and business income. Each item grows annually by the inflation rate when indexing is enabled. Note: each income item may have its own index rate, which overrides this setting.
Future Value = Current Value × (1 + Inflation Rate) ^ Years
Example: $100,000 income with 3% inflation → Year 10: $134,392 | Year 20: $180,611 | Year 30: $242,7264. Real vs Nominal Returns
Investment returns should be nominal (not inflation-adjusted) when using this assumption. The system will show real purchasing power by comparing nominal growth against inflation.
Example: 7% nominal return - 3% inflation = 4% real return (actual purchasing power growth)5. Sensitivity Analysis
Test scenarios with different inflation rates to understand impact on retirement security. Higher inflation requires larger nest eggs or higher withdrawal rates to maintain lifestyle.
Example: 2% inflation: $1M sufficient | 4% inflation: $1.4M needed for same purchasing power
Real-world context
Federal Reserve Target
The Federal Reserve targets 2% long-term inflation as optimal for economic growth. This is measured by Personal Consumption Expenditures (PCE) index. Most financial plans use 2.5-3.5% as a conservative range that accounts for possible overshooting and healthcare cost inflation.
IRS reference: Historical data from Bureau of Labor Statistics CPI-U
Social Security COLA
Social Security benefits receive Cost of Living Adjustments (COLA) based on CPI-W (Consumer Price Index for Urban Wage Earners). Historical COLA averages ~2.5% but varies widely (0% in 2010-2011, 8.7% in 2023). Using your inflation assumption for SS indexing simplifies modeling.
Tax Bracket Indexing
IRS adjusts tax brackets annually for inflation using Chained CPI. Brackets typically increase 2-3% per year. Enabling tax bracket indexing prevents 'bracket creep' (moving into higher brackets just from inflation). TCJA brackets were set to expire after 2025. Advisors should verify the current bracket structure with IRS guidance, as Congress may have extended or modified these provisions.
What drives the result
Sets the baseline rate for all inflation indexing. Higher rates increase future income projections but also future tax liabilities and required retirement savings.
2% inflation: $100k income → $148k in year 20 | 4% inflation: $100k income → $219k in year 20
When enabled, tax bracket thresholds increase annually by inflation rate. Prevents bracket creep and provides more realistic tax projections.
24% bracket starts at $201,050 (2025) → $244,262 in year 10 with 2% indexing
Should be set as nominal return (before inflation). Real return = Nominal Return - Inflation Rate. This determines actual wealth growth.
7% nominal return - 3% inflation = 4% real growth in purchasing power
Assumptions
- Inflation rate remains constant throughout projection period (reality varies)
- All indexed items increase at same rate, but can be overridden individually
- Tax brackets indexed annually (current law subject to Congressional action; consult current IRS guidance for post-2025 bracket structure)
- Social Security COLA matches inflation assumption (simplified model)
Limitations
- Does not account for potential deflationary periods
- Assumes smooth annual increases (reality: lumpy year-to-year changes)
- Does not model purchasing power parity adjustments for relocations
Related
This page explains how Stratum models this calculation. It is educational material for financial professionals, not tax or legal advice, and tax law changes. Verify current figures against primary IRS sources before relying on them with a client.