Zoho Sheet DISC Function: Discount Rates and Day-Count Checks
Calculate annual discount rates with a complete date dataset, redemption-based arithmetic controls and clear product-specific error limits.
Verification status: See the evidence and test scope described in this guide. How formula examples are checked
DISC returns an annual discount rate from a security’s purchase price, redemption value and holding dates. The discount is measured against the redemption amount. That denominator matters: a return measured against the amount invested is a different rate, even when both start with the same difference in money amounts.
Syntax and argument contract
DISC(settlement; maturity; price; redemption_value; [basis])
settlement is the purchase date; maturity is the redemption date. price is the purchase price and redemption_value is the amount received at maturity. Use the same monetary unit and scale for both amounts. This is not a coupon-frequency function.
The optional basis defaults to 0. Zoho documents 0 as US NASD 30/360, 1 as actual days with an actual-length year, 2 as actual days/360, 3 as actual days/365 and 4 as European 30/360. Those are distinct conventions. This guide uses explicit 3 for reproducible actual-day examples; omitting the final argument would change the requested convention.
Construct dates with DATE(year;month;day) rather than ambiguous text. The Zoho DATE reference documents that construction. The examples use semicolons as shown in Zoho’s help; the actual editor’s locale and accepted separators should be checked before importing formulas.
Availability and evidence scope
The official DISC reference was retrieved October 15, 2026. It documents the rolling web service but does not establish the first release or last functioning version. Both historical endpoints remain unknown, and mobile/offline parity is not certified by the web entry.
Expected numbers below are independent simple-interest or discount-model calculations from fully specified inputs, not captured native Zoho output. The source lists syntax, argument meanings, day-count options and sample results, but its embedded example input cells are not visible in the retrieved text. Those hidden datasets are not reconstructed or claimed as executed tests. The ordinary positive, forward-date examples do not resolve every boundary or coercion behavior.
Complete discount worksheet
Create a sheet named Discount with the following entries:
| Cell | Label or input |
|---|---|
| A1 | Settlement |
| B1 | Maturity |
| C1 | Purchase |
| D1 | Redemption |
| E1 | Basis |
| A2 | =DATE(2026;4;1) |
| B2 | =DATE(2026;7;1) |
| C2 | 98 |
| D2 | 100 |
| E2 | 3 |
Enter =DISC(A2;B2;C2;D2;E2) in F2. The independent expected decimal rate is 0.0802197802, or approximately 8.02197802%. There are 91 actual days between the two dates, and the discount is two units on a redemption value of 100.
A transparent arithmetic control is =(D2-C2)/D2*365/(B2-A2). It calculates 2/100 times 365/91. Formatting its decimal result as a percentage changes appearance, not the underlying rate. Multiplying by 100 and also applying percentage formatting would inflate the displayed percentage.
Example: compare purchase prices with fixed dates
Repeat the dates, redemption 100 and basis 3 in rows 3–5, using purchase prices 95, 98 and 99. The expected DISC rates are 0.2005494505, 0.0802197802 and 0.0401098901. The lower purchase price produces the larger discount because redemption and elapsed time remain fixed.
These are annualized simple rates. They are not the holding-period fractions themselves: those fractions are 5%, 2% and 1%, respectively. They also are not effective compound annual returns. Label the output with the selected day-count convention.
Advanced: separate discount rate from investment return
For the 98-to-100 example, an amount-invested annual rate uses =(D2-C2)/C2*365/(B2-A2), independently 0.0818569186. Its denominator is 98 instead of 100, so it is larger than DISC’s 0.0802197802.
This distinction is useful when reconciling differently labeled rate columns in an imported workbook. A disagreement does not necessarily indicate a rounding problem. First inspect whether the denominator is purchase price or redemption value, then inspect the year basis and whether compounding was introduced.
Advanced: test scale and day-count sensitivity
Multiply both C2 and D2 by 100. Purchase 9800 and redemption 10000 yield the same independent DISC rate because the common scale cancels. Multiplying only one amount does not preserve the contract.
Keeping the original dates and amounts but requesting basis 2 gives the independent actual/360 rate 0.0791208791. Basis 3 uses 365 instead of 360 in the annualizing numerator. Do not assume either of the 30/360 conventions gives 91 counted days, and do not use this guide’s actual-day arithmetic as a universal month-end implementation.
Documented errors and unresolved endpoints
Zoho lists #NUM! when price or redemption is less than zero, basis is outside 0–4, or settlement is after maturity. Its wording does not exclude zero monetary values or equal dates in that same rule. This guide does not convert those omissions into a claim that zero redemption or a zero-day interval works: the independent formula has a denominator problem there.
Use strictly positive amounts and a later maturity for the worked cases. Exact errors for equal dates, zero redemption, fractional basis values or malformed text dates remain untested. Shared type/name/reference errors are listed by the help, but its generic lookup-error text is not a DISC-specific lookup operation.
If an output looks implausible, check date parsing, the monetary scale, basis, decimal-versus-percentage input and the rate denominator. These fictional figures demonstrate a spreadsheet calculation, not a security recommendation or a complete investment-return assessment.