TBillLab

13 Week T-Bill Calculator

Yield and profit on a 13-week (91-day) T-bill.

Your T-bill numbers never leave your browser — all math runs locally.
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Try: Face value=1000, Purchase price=988, Days to maturity=91 → $1,000, $988, $12, 0.0475%, 0.0487%, 0.0487%

How to use

The 13-week bill is the classic 3-month T-bill and a benchmark for short-term rates.

FAQ

Is 13 weeks the same as 3 months?

Close — 91 days vs a calendar quarter, the standard convention for T-bills.

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