Government Bond Calculator USA 2026

Government bonds are the bedrock of conservative portfolio construction and cash management — and they're also among the most misunderstood asset classes for retail investors. The relationship between price and yield moves in opposite directions: when interest rates rise, existing bond prices fall; when rates fall, prices rise. Understanding why this happens — and how to calculate the impact — is essential for anyone holding bonds outside of a fund.

For US investors, Treasury bonds offer the additional advantage of being exempt from state and local income taxes. For an investor in California (13.3% state tax) or New York (10.9%), a 4.5% Treasury yield is equivalent to roughly 5.1-5.0% taxable yield — making Treasuries more competitive than they appear at face value compared to CDs and corporate bonds.

Duration is the key risk metric for bonds: it measures the sensitivity of price to interest rate changes. A bond with duration of 7 years will fall approximately 7% in price for each 1% rise in interest rates. Short-duration bonds (T-bills, 2-year notes) have much lower price sensitivity than long-duration bonds (30-year Treasuries), which helps explain why many investors in 2022-2023 who held long-term bonds saw dramatic unrealized losses.