DISC Function in Microsoft Excel: Syntax, Examples & Troubleshooting
Find a security discount rate in Excel with DISC. Calculate a 90-day example, distinguish redemption-based discount from investment yield and audit basis and price units.
Verification status: See the evidence and test scope described in this guide. How formula examples are checked
Quick answer: DISC annualizes a security’s discount relative to its redemption value. Its denominator is redemption, which distinguishes a discount quotation from a return calculated on the price paid.
Syntax and arguments
=DISC(settlement, maturity, pr, redemption, [basis])
Settlement, maturity, pr and redemption are required. pr is the price per 100 face value and redemption is the redemption amount on the same scale. Basis is optional.
Use real date values or DATE formulas for settlement and maturity. Settlement is the purchase settlement date, which is not necessarily the original issue date. The optional basis selects 0 or omitted = US (NASD) 30/360; 1 = actual/actual; 2 = actual/360; 3 = actual/365; 4 = European 30/360. Microsoft documents that settlement, maturity and basis are truncated to integers; time-of-day fractions are not used for intraday accrual.
The examples use January 15 through April 15, 2026, an independently checked 90-day interval. Actual/360 therefore gives a year fraction of 90/360 = 0.25. Enter =DATE(2026,1,15) in B2, =DATE(2026,4,15) in B3 and 2 in B6. Using fixed dates rather than TODAY makes the expected results reproducible.
Worked example: a price of 98 redeemed at 100
- Enter 98 in B4 (price) and 100 in B5 (redemption).
- In D2 enter
=DISC(B2,B3,B4,B5,B6). - Expected result: 0.08, displayed as 8% with Percentage formatting.
The independent calculation is (100-98)/100*360/90 = 0.08. The price difference of 2 is 2% of redemption over the quarter; annualizing on the 360-day basis multiplies it by four.
Second example: change the annual day-count denominator
=DISC(B2,B3,B4,B5,3) is expected to return approximately 0.08111111111, or 8.111111111%. The actual 90 days remain unchanged, but basis 3 annualizes them against 365 rather than 360: 2/100*365/90.
The default basis is not actual/360. With these specific equal-day-of-month dates, omitted US 30/360 happens to give 8% too; that coincidence must not obscure the omitted argument’s meaning.
Advanced application: reconcile discount and investment return
The same security earns 2 on a price of 98 over the interval. Dividing by the invested price gives 2/98*360/90, approximately 8.163265306%. This is higher than the 8% redemption-based discount rate even though the cash flows are identical.
An audit sheet can keep the two denominators side by side. A price of 96 instead produces a DISC result of 16%, from 4/100*4, while the corresponding simple annual return on price is 4/96*4 = 16.66666667%. Do not label the DISC output as a compound annual growth rate or an interest-on-investment yield.
The equation image in the Microsoft page labels its price term “par,” while the actual argument table names the purchase price pr. The examples here use the documented price input, 98 per 100, and redemption 100. They do not substitute an extra face-value argument that is absent from the function’s syntax.
Troubleshooting and edge cases
Microsoft documents #VALUE! for invalid date inputs and #NUM! for settlement greater than or equal to maturity or basis outside 0 through 4. It also documents #NUM! when price or redemption is zero or negative.
A percent-formatted result and its stored decimal are the same rate: 8% is 0.08. Do not multiply a rate by 100 and then apply percentage formatting again. Keep a price per 100 separate from the entire investment amount, and preserve full precision until the reporting step.
Actual/actual and the two 30/360 variants have their own date rules; one ordinary 90-day example does not certify every leap-year or month-end boundary. Match the contract’s convention rather than choosing whichever basis produces the most attractive number. The examples explain calculation mechanics and exclude transaction costs, taxes and advice about a real investment.
Compatibility and verification
Microsoft’s reference checked on October 17, 2026 lists: Excel for Microsoft 365 Excel for Microsoft 365 for Mac Excel 2024 Excel 2024 for Mac Excel 2021 Excel 2021 for Mac Excel 2019 Excel 2016. This current support list does not establish the first release. The introduction version and last functioning version have not been established from the reviewed documentation. No retirement is asserted.
Example verification: Expected numerical results are independently calculated; text and shape expectations follow the documented contract. These examples have not been tested in Microsoft Excel. No screenshot or native execution is claimed.
Related guides and source
DATE in Excel | DAYS in Excel | ROUND in Excel
- Microsoft DISC reference, retrieved October 17, 2026.