Understanding US Treasury Bills in Google Sheets

August 7th, 2026

US Treasury bills (T-bills) are short-term government securities sold at a discount and redeemed at face value — no coupon payments along the way. Google Sheets has three dedicated functions for them: TBILLPRICE, TBILLYIELD, and TBILLEQ. This guide explains what each number means and works through concrete formulas.

What a T-bill is (in one paragraph)

You buy a T-bill for less than $100 face (per $100 of par), hold it to maturity (often 4, 13, 26, or 52 weeks), and receive $100. The gap between purchase price and par is your return. Because there is no coupon, pricing is driven by a discount rate and the fraction of a year left until maturity — not by periodic interest math like a coupon bond.

Three related numbers: price, discount yield, bond-equivalent

| Concept | What it answers | Sheets function | | --- | --- | --- | | Price | Dollars per $100 face, given a discount rate | TBILLPRICE | | Discount yield | Market-style T-bill yield from a price | TBILLYIELD | | Bond-equivalent yield | Annualized yield comparable to coupon bonds | TBILLEQ |

Discount yield is the conventional quote for T-bills: it annualizes the dollar discount on a 360-day year using face value in the denominator. Bond-equivalent yield (also called investment yield) annualizes the return on the money you actually paid, on a 365-day basis — closer to how you compare a T-bill to a note or bond.

TBILLPRICE — price from settlement, maturity, and discount

TBILLPRICE returns the price per $100 face value:

=TBILLPRICE(settlement, maturity, discount)

Example: settle 15 January 2026, mature 15 July 2026 (about 181 days), discount rate 5%:

=TBILLPRICE(DATE(2026,1,15), DATE(2026,7,15), 0.05)

That returns about 97.486 — you pay roughly $97.49 per $100 of face. The bill matures at 100; the $2.51 discount is the return if held to maturity.

Shorter bill, same discount rate — less total discount, higher price:

=TBILLPRICE(DATE(2026,1,15), DATE(2026,4,15), 0.05)

About 98.75 per $100 face for a ~90-day bill at 5% discount.

TBILLYIELD — discount yield from a market price

When you observe a purchase price instead of a quoted discount, TBILLYIELD backs out the discount yield:

=TBILLYIELD(settlement, maturity, price)

Using the first example in reverse — price 97.486 for the Jan–Jul bill:

=TBILLYIELD(DATE(2026,1,15), DATE(2026,7,15), 97.486)

Returns about 0.05 (5%), matching the discount we priced from. Another worked price:

=TBILLYIELD(DATE(2026,3,1), DATE(2026,8,28), 98.2)

A bill bought at 98.2 with ~180 days to maturity shows a discount yield a bit under 4% — cheaper discount dollars, lower yield.

TBILLEQ — bond-equivalent yield from the discount rate

TBILLEQ converts a T-bill discount rate into a bond-equivalent (investment) yield so you can compare apples-to-apples with coupon securities:

=TBILLEQ(settlement, maturity, discount)

=TBILLEQ(DATE(2026,1,15), DATE(2026,7,15), 0.05)

Returns roughly 0.0519 (~5.19%) — higher than the 5% discount rate because bond-equivalent yield is based on purchase price and a 365-day year, not on face and 360 days.

For a 52-week-style span:

=TBILLEQ(DATE(2026,1,15), DATE(2027,1,14), 0.04)

About 0.042 — again slightly above the 4% discount quote.

Worked mini-model in a sheet

| Cell | Input | | --- | --- | | B1 | Settlement =DATE(2026,1,15) | | B2 | Maturity =DATE(2026,7,15) | | B3 | Discount rate 0.05 |

=TBILLPRICE(B1, B2, B3)
=TBILLEQ(B1, B2, B3)
=TBILLYIELD(B1, B2, B4)

Put the price result in B4 (or reference the TBILLPRICE cell). TBILLYIELD on that price should recover B3; TBILLEQ gives the comparable annualized yield for portfolio math.

Common mistakes

• Maturity more than one year from settlement. T-bill functions are for bills with term ≤ 1 year; longer instruments need bond functions like PRICE / YIELD.
• Confusing discount yield with return on cash invested. A 5% discount is not "I earn 5% on the money I paid." Use TBILLEQ (or price + holding period) for that comparison.
• Price must be per $100 face. TBILLYIELD expects a price like 98.5, not a full notional dollar amount for a $10,000 bill (scale to per-100 first).
• Settlement ≥ maturity. Both dates must be valid and settlement before maturity or you get #NUM!.

Which function should you pick?

| Goal | Function | | --- | --- | | Fair price from a discount quote | TBILLPRICE | | Discount yield from a traded price | TBILLYIELD | | Bond-like annualized yield from discount | TBILLEQ |

Going further

For loans, NPV/IRR, and coupon bonds in the same toolkit, see Mastering Financial Functions in Google Sheets. Reference pages: TBILLPRICE, TBILLYIELD, and TBILLEQ.