US Savings Bond Calculator Series I

Series I Bond Value Formula:

\[ V = P \times \left(1 + \frac{\text{fixed} + 2 \times \text{inflation} + \text{fixed} \times \text{inflation}}{2}\right)^{2 \times y} \]

Purchase Amount (P):

USD

Fixed Annual Rate:

decimal

Semiannual Inflation Rate:

decimal

Years Held (y):

years

Current Value (V):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the US Series I Savings Bond?

US Series I Savings Bonds are government-issued savings bonds that offer a combination of a fixed interest rate and an inflation-adjusted rate. They are designed to protect investors from inflation while providing a guaranteed return.

2. How Does the Calculator Work?

The calculator uses the Series I Bond value formula:

\[ V = P \times \left(1 + \frac{\text{fixed} + 2 \times \text{inflation} + \text{fixed} \times \text{inflation}}{2}\right)^{2 \times y} \]

Where:

$ V $ — Current value of the bond (USD)
$ P $ — Purchase amount (USD)
$ \text{fixed} $ — Fixed annual interest rate (decimal)
$ \text{inflation} $ — Semiannual inflation rate (decimal)
$ y $ — Number of years the bond has been held

Explanation: The formula combines the fixed rate with twice the semiannual inflation rate, plus their product, then compounds this combined rate semiannually over the holding period.

3. Importance of Series I Bond Calculation

Details: Accurate calculation helps investors understand the real return on their Series I Bonds, accounting for both fixed interest and inflation protection components over time.

4. Using the Calculator

Tips: Enter the purchase amount in USD, fixed annual rate as a decimal (e.g., 0.035 for 3.5%), semiannual inflation rate as a decimal, and years held. All values must be non-negative.

5. Frequently Asked Questions (FAQ)

Q1: What are the current Series I Bond rates?
A: Rates are announced every May and November. Check TreasuryDirect.gov for current fixed and inflation rates.

Q2: How long must I hold Series I Bonds?
A: Minimum holding period is 1 year. If redeemed within first 5 years, you lose the last 3 months of interest.

Q3: Are there purchase limits for Series I Bonds?
A: Yes, currently $10,000 per person per year electronically, plus up to $5,000 in paper bonds via tax refund.

Q4: How is the inflation rate determined?
A: Based on the Consumer Price Index for All Urban Consumers (CPI-U) published by the Bureau of Labor Statistics.

Q5: Are Series I Bonds taxable?
A: Federal income tax applies, but state and local taxes are exempt. Tax can be deferred until redemption or maturity.