Free US Treasury Bill Calculator: T-Bill Yield, Price & Discount Rate

What Is a U.S. Treasury Bill?

A U.S. Treasury bill (T-Bill) is a short-term government debt security issued by the U.S. Department of the Treasury. Unlike Treasury notes and bonds, T-Bills do not pay periodic interest (coupon) payments. Instead, they are sold at a discount to their face value, and the investor receives the full face value at maturity. The difference between the purchase price and the face value represents the investor's return.

T-Bills are considered one of the safest investments available because they are backed by the full faith and credit of the United States government. They are widely used by individual investors, institutions, and central banks as a risk-free benchmark and a tool for managing short-term cash positions.

T-Bill Maturities

The U.S. Treasury issues bills with the following standard maturities:

4-week (28 days): The shortest standard maturity, auctioned weekly. Ideal for very short-term cash management.
8-week (56 days): Auctioned weekly, offering slightly higher yields than 4-week bills.
13-week (91 days): Also known as the 3-month T-Bill, auctioned weekly. One of the most actively traded maturities.
17-week (119 days): Auctioned every four weeks, providing an intermediate short-term option.
26-week (182 days): The 6-month T-Bill, auctioned weekly. A popular benchmark for money market rates.
52-week (364 days): The longest standard T-Bill maturity, auctioned every four weeks.

How T-Bill Pricing Works

T-Bills are sold at a discount to their face value. The purchase price is determined by the discount rate established at auction. The formula for calculating the purchase price is:

Price = Face Value × (1 - Discount Rate × Days to Maturity / 360)

For example, a 26-week T-Bill with a face value of $10,000 and a discount rate of 5.00% would have a purchase price of $9,747.22. At maturity, the investor receives the full $10,000, earning $252.78 in interest.

Understanding T-Bill Yield Measures

There are several ways to express the yield on a Treasury bill, each serving a different purpose. Understanding these yield measures is essential for comparing T-Bills with other fixed-income investments.

Bank Discount Yield (BDY)

The Bank Discount Yield is the rate quoted at T-Bill auctions. It uses the face value as the investment base and a 360-day year:

BDY = ((Face Value - Price) / Face Value) × (360 / Days to Maturity)

BDY understates the true return because it uses face value (not the actual amount invested) as the denominator and assumes a 360-day year.

Money Market Yield (MMY)

The Money Market Yield corrects one limitation of BDY by using the purchase price as the base, but still uses a 360-day year:

MMY = ((Face Value - Price) / Price) × (360 / Days to Maturity)

MMY is useful for comparing T-Bills with other money market instruments like commercial paper and certificates of deposit that also use a 360-day convention.

Bond Equivalent Yield (BEY)

The Bond Equivalent Yield uses the purchase price as the base and a 365-day year, making it directly comparable to semiannual coupon bonds:

BEY = ((Face Value - Price) / Price) × (365 / Days to Maturity)

For T-Bills with maturities greater than 182 days, a more complex coupon-equivalent formula is used to account for the semiannual compounding convention of coupon bonds.

Effective Annual Yield (EAY)

The Effective Annual Yield accounts for compounding and represents the true annualized return assuming the investment is reinvested at the same rate:

EAY = (1 + (Face Value - Price) / Price)^365/Days - 1

EAY provides the most accurate measure of annualized return and is the best metric for comparing T-Bills with other investments across different compounding frequencies.

How to Use This Treasury Bill Calculator

Yield Calculator: Enter the face value, purchase price, and days to maturity (or settlement and maturity dates). Click Calculate to see all four yield measures — Bank Discount Yield, Money Market Yield, Bond Equivalent Yield, and Effective Annual Yield.
Price Calculator: Enter the face value, discount rate, and days to maturity. Click Calculate to determine the purchase price and see the dollar discount and total return.
Quick Maturity Buttons: Use the preset buttons (4W, 8W, 13W, 17W, 26W, 52W) to quickly set standard T-Bill maturities.

Why Use Our Treasury Bill Calculator?

Four Yield Metrics

Calculate BDY, MMY, BEY, and EAY simultaneously to compare T-Bills with any fixed-income investment.

Price & Yield Modes

Calculate yields from a known price, or determine the purchase price from a known discount rate.

Standard Maturity Presets

Quick-select buttons for all six standard T-Bill maturities — 4W, 8W, 13W, 17W, 26W, and 52W.

Completely Free

No registration, no limits. Use our Treasury bill calculator as many times as you need.

Frequently Asked Questions

What is a U.S. Treasury bill?

A U.S. Treasury bill (T-Bill) is a short-term government debt obligation issued by the U.S. Department of the Treasury with a maturity of one year or less. T-Bills are sold at a discount to their face value and do not pay periodic interest (coupon) payments. Instead, the investor earns the difference between the purchase price and the face value at maturity.

What T-Bill maturities are available?

The U.S. Treasury issues T-Bills with standard maturities of 4 weeks (28 days), 8 weeks (56 days), 13 weeks (91 days), 17 weeks (119 days), 26 weeks (182 days), and 52 weeks (364 days). The Treasury also occasionally issues cash management bills with non-standard maturities.

What is the difference between Bank Discount Yield and Bond Equivalent Yield?

Bank Discount Yield (BDY) is calculated using the face value as the base and a 360-day year, which is the convention used in T-Bill auctions. Bond Equivalent Yield (BEY) uses the purchase price as the base and a 365-day year, making it directly comparable to coupon-bearing bonds. BEY is always higher than BDY for the same T-Bill.

How are T-Bills taxed?

Interest income from T-Bills is subject to federal income tax but is exempt from state and local income taxes. The discount earned (face value minus purchase price) is treated as interest income for tax purposes and is reported in the year the T-Bill matures or is sold.

What is the minimum investment for T-Bills?

The minimum purchase amount for T-Bills is $100, and they are sold in increments of $100. You can buy T-Bills directly from the U.S. Treasury through TreasuryDirect.gov, or through a bank or broker.

Are T-Bills a safe investment?

T-Bills are considered one of the safest investments in the world because they are backed by the full faith and credit of the U.S. government. They carry virtually no credit risk or default risk. However, they are subject to inflation risk and interest rate risk if sold before maturity.

Is this Treasury bill calculator free to use?

Yes, the Pineify US Treasury Bill Calculator is completely free to use with no registration required. You can calculate T-Bill yields, purchase prices, and discount rates as many times as you need at no cost.

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