TIPS vs. Nominal Treasury Calculator
Compare a TIPS with a nominal Treasury using comparable quoted yields and a holding-period inflation assumption. The calculator converts Treasury-style quoted yields before showing breakeven inflation, ending value, and purchasing power.
Higher projected valueTIPS
- Exact breakeven inflation
- 2.49%
- Expected inflation margin
- 0.01%
- Nominal Treasury ending value
- $15,605.09
- TIPS ending value
- $15,619.46
- Nominal Treasury purchasing power
- $12,190.67
- TIPS purchasing power
- $12,201.90
- Difference at the horizon
- $14.37
Assumes comparable-maturity securities are held to maturity and interim cash flows compound consistently with their yields.
Does not model market-price changes, taxes, transaction costs, CPI indexation lag, or the full value of the TIPS deflation floor.
How to use this calculator
- Enter the same amount you would invest in either Treasury security.
- Enter comparable-maturity nominal and TIPS yields, using the quoted yield convention shown by your source.
- Enter the average annual inflation rate you want to test and the number of years you expect to hold the securities.
- Compare the breakeven rate with your inflation assumption, then review the ending values and purchasing-power figures.
How the TIPS and nominal Treasury comparison works
A nominal Treasury pays dollars that do not change with inflation. A Treasury Inflation-Protected Security, or TIPS, has a real yield and an inflation-adjusted principal. The useful comparison is therefore not simply the nominal yield minus the real yield. Treasury yields are commonly quoted with semiannual bond-equivalent compounding, while the inflation assumption is annual.
Let I be the starting investment, n the nominal Treasury yield, r the TIPS real yield, pi the annual inflation assumption, and T the holding period. For a Treasury quoted yield, use q = 2; for an effective annual yield, use q = 1. The calculator first converts both yields:
N = (1 + n / q)^q - 1 and R = (1 + r / q)^q - 1
The exact annual breakeven inflation rate is then B = (1 + N) / (1 + R) - 1. At that rate, both investments have the same projected ending value. The nominal Treasury grows to Vn = I(1 + N)^T. The TIPS projection grows to Vt = I[(1 + R)(1 + pi)]^T. The difference shown is Vt - Vn.
Why purchasing power matters
Dollar values at maturity are not directly comparable to today’s dollars when inflation is expected. The calculator divides each ending value by cumulative inflation. That gives nominal Treasury purchasing power of Vn / (1 + pi)^T. For the simplified TIPS model, inflation cancels out and purchasing power is I(1 + R)^T.
The nominal yield, real yield, expected inflation, and holding period all matter. A small annual gap compounds over a long maturity. Matching the remaining maturities matters too: otherwise duration, reinvestment risk, and changes in market price can overwhelm this held-to-maturity comparison.
What the calculator leaves out
This is a constant-inflation projection, not a bond-pricing model. It assumes both securities are held to maturity and that interim cash flows can be reinvested consistently with their yields. It does not model coupon dates, the three-month CPI indexation lag, accrued interest, bid-ask spreads, taxes, transaction costs, individual TIPS index ratios, or changing market prices.
In deflation, a TIPS has a maturity principal floor that can matter. The calculator warns when expected inflation is negative but does not fully value that option. Market breakeven inflation can also reflect inflation-risk and liquidity premiums, so it is not a pure forecast of future CPI.
Worked example
Suppose you invest $10,000 for 10 years. A 4.50% Treasury quoted yield converts to an effective annual yield of 4.550625%, while a 2.00% TIPS quoted real yield converts to 2.01%. The exact breakeven inflation rate is about 2.49%.
At 2.50% expected annual inflation, the nominal Treasury grows to about $15,605 and the TIPS grows to about $15,619. The TIPS has about $14 more projected value at the horizon. In today’s purchasing power under that inflation assumption, the nominal Treasury is about $12,191 and the TIPS is about $12,202.
Common questions
What is the breakeven inflation rate for TIPS?
It is the constant annual inflation rate at which a TIPS and a comparable nominal Treasury have the same projected return. This calculator converts the yields to effective annual rates before solving for it. That is more exact than subtracting the stated yields when they use semiannual quotation.
Should I buy TIPS or nominal Treasury bonds?
TIPS project a higher ending value when your inflation assumption is above the calculated breakeven rate; a nominal Treasury projects more when it is below it. The choice also depends on maturity, taxes, liquidity, and whether you could need to sell before maturity. The projection is a comparison tool, not a recommendation.
Why is exact breakeven inflation different from subtracting the two yields?
Yield subtraction ignores compounding. The nominal return must equal the product of the real return and inflation, so the exact relationship is nominal effective yield divided by one plus real effective yield, minus one. The gap is usually small, but it grows in importance with higher yields and longer holding periods.
How do Treasury quoted yields differ from effective annual yields?
Treasury bond-equivalent quotes use a semiannual convention. An effective annual yield includes the effect of both six-month periods over a year. Choose Treasury quoted yield for a usual Treasury market quote and effective annual yield only when your source already reports annual compounding.
Does breakeven inflation equal the market’s inflation forecast?
No. The market breakeven rate is a pricing difference between nominal Treasuries and TIPS, not a clean survey forecast. It can include compensation for inflation uncertainty and differences in liquidity between the two markets.