1-Year T-Bill Calculator (52-Week Treasury Bill Yield & Return Calculator)
The 1-year T-Bill is the longest T-Bill duration and usually the highest yielding. Enter your investment amount and current rate to see exactly what you pay, what you earn, and your annual return.
💡 A 1-year T-Bill usually offers the highest yield — but only if interest rates are stable or falling.
This is the amount you get back at maturity. Minimum $100.
Check latest rate → TreasuryDirect.gov (auctioned every 4 weeks)
Fixed at 364 days (52 weeks) — note: T-Bills use 364 days, not 365.
How to Calculate 1-Year T-Bill Returns
- Enter your investment amount (face value)
- Apply the discount rate over 364 days
- Calculate the purchase price (face value minus discount)
- Compute the annualized yield based on what you paid
This calculator performs all these steps instantly and shows your exact return.
What is a 1-Year T-Bill?
A 1-year Treasury Bill (also called a 52-week T-Bill) is the longest available T-Bill duration, maturing in 364 days. It is auctioned every four weeks by the U.S. Treasury and typically offers the highest yield of any T-Bill in normal market conditions. Like all T-Bills, it is sold at a discount and redeemed at full face value at maturity.
How 1-Year T-Bill Returns Are Calculated (Step-by-Step)
The formula (the calculator does this for you):
- Your profit = Investment × Rate ÷ 100 × 364 ÷ 360
- You pay upfront = Investment − Your profit
- Annual return = (Profit ÷ You pay) × (365 ÷ 364) × 100
Step 1 — Your profit:
$10,000 × 4.5% × (364 ÷ 360) = $455.00
Step 2 — What you pay today:
$10,000 − $455.00 = $9,545.00
Step 3 — Your annual return:
($455 ÷ $9,545) × (365 ÷ 364) × 100 = 4.78%
The return is slightly above 4.5% because it is calculated on what you paid ($9,545), not the full $10,000. And note: 52-week T-Bills use 364 days, not 365 — this is U.S. Treasury convention.
Who Should Use the 1-Year T-Bill?
The 52-week T-Bill is best for investors who are confident they won't need the money for a full year and want to lock in the highest available T-Bill yield.
- Investors who want maximum yield and won't need cash for 12 months
- Locking in high rates when the Fed is expected to cut rates
- Planning for a known future expense exactly one year away
- Investors building a T-Bill ladder — the 52-week is the longest rung
When to Choose 1-Year vs Shorter Durations
| Rate Environment | Best Choice | Reason |
|---|---|---|
| 🔻 Rates Falling | ✅ 52-Week T-Bill | Lock in today's high rate before it drops |
| ➡️ Rates Stable | ✅ 52-Week or 26-Week | Either works — go longer for slightly more yield |
| 🔺 Rates Rising | ❌ Avoid 52-Week | Stay short — reinvest at higher rates every few weeks |
| ❓ Uncertain | ⚖️ T-Bill Ladder | Mix durations to hedge both directions |
Not sure which direction rates are heading? Read our Best T-Bill Duration Guide for a full analysis including the inverted yield curve explained.
1-Year T-Bill vs Other Durations
| Duration | Days | Earnings on $10K at 4.5% | Annualized Yield | Liquidity |
|---|---|---|---|---|
| 4-Week | 28 | ~$35.00 | ~4.58% | ⭐⭐⭐⭐⭐ |
| 13-Week | 91 | ~$113.75 | ~4.63% | ⭐⭐⭐⭐ |
| 26-Week | 182 | ~$227.50 | ~4.68% | ⭐⭐⭐ |
| 52-Week | 364 | ~$455.00 | ~4.77% | ⭐⭐ |
Tax Treatment of 1-Year T-Bills
Like all T-Bills, 1-year T-Bill earnings are subject to federal income tax but are exempt from state and local taxes. Because the 52-week T-Bill generates the largest absolute earnings of any T-Bill duration, the state tax saving is also the largest. In California at 13.3% state tax, you save approximately $60 in state taxes on a $10,000 52-week T-Bill at 4.5% compared to a CD.
Find your real after-tax yield and the CD rate needed to match your T-Bill.
Find the exact CD rate that would beat your 1-year T-Bill after all taxes.
Related Calculators
New to T-Bills? What Are Treasury Bills — Complete Guide · Are T-Bills Worth It? · Best T-Bill Duration Guide
Frequently Asked Questions (FAQ)
Is a 1-year T-Bill a good investment?
Yes, a 1-year T-Bill is a good investment for short-term safety and predictable returns. It is backed by the U.S. government and typically offers one of the highest yields among T-Bill durations.
How much can I earn from a 1-year T-Bill?
You can earn around $450 to $500 on a $10,000 1-year T-Bill depending on the rate. The exact earnings depend on the current discount rate and your investment amount.
When should I choose a 1-year T-Bill over shorter durations?
Choose a 1-year T-Bill when interest rates are expected to fall. Locking in a higher rate protects your returns compared to shorter-term T-Bills that must be reinvested at lower rates.
How often is the 1-year T-Bill auctioned?
The 1-year (52-week) T-Bill is auctioned every four weeks by the U.S. Treasury. This makes it less frequent than shorter-duration T-Bills.