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yearfrac

Fraction of year between dates

Syntax

```YearFraction = yearfrac(StartDate, EndDate, Basis)
```

Arguments

 StartDate Enter as serial date numbers or date strings. EndDate Enter as serial date numbers or date strings. Basis (Optional) Day-count basis of the instrument. A vector of integers.0 = actual/actual (default)1 = 30/360 (SIA)2 = actual/3603 = actual/3654 = 30/360 (BMA)5 = 30/360 (ISDA)6 = 30/360 (European)7 = actual/365 (Japanese)8 = actual/actual (ICMA)9 = actual/360 (ICMA)10 = actual/365 (ICMA)11 = 30/360E (ICMA) 12 = actual/actual (ISDA)13 = BUS/252 For more information, see basis.

All specified arguments must be number of instruments (NUMINST)-by-1 or 1-by-NUMINST conforming vectors or scalar arguments.

Description

YearFraction = yearfrac(StartDate, EndDate, Basis) returns a fraction based on the number of days between dates StartDate and EndDate using the given day-count basis. Note, the number of days in a year (365 or 366) is equal to the number of days in the calendar year after the StartDate. If EndDate is earlier than StartDate, Fraction is negative.

Definitions

The difference between yearfrac and date2time is that date2time counts full periods as a whole integer, even if the number of actual days in the periods are different. yearfrac does not count full periods. For example,

```yearfrac('1/1/2000', '1/1/2001', 9)

ans =

1.0167```

yearfrac for Basis 9 (ACT/360 ISMA) will calculate 366/360 = 1.0167. So, even if the dates have the same month and date, with a difference of 1 in the year, the returned value may not be exactly 1. On the other hand, date2time will calculate one full year period:

```date2time('1/1/2000', '1/1/2001', 1, 9)

ans =

1```

Examples

expand all

Compute yearfrac When the Calendar Year After the StartDate is Not a Leap Year

Given a Basis of 0 and a Basis of 1, compute yearfrac.

Define the StartDate and EndDate using a Basis of 0.

```YearFraction = yearfrac('14 mar 01', '14 sep 01', 0)
```
```YearFraction =

0.5041

```

Define the StartDate and EndDate using a Basis of 1.

```YearFraction = yearfrac('14 mar 01', '14 sep 01', 1)
```
```YearFraction =

0.5000

```

Compute yearfrac When the Calendar Year After the StartDate is a Leap Year

Given a Basis of 0, compute yearfrac when the calendar after StartDate is in a leap year.

Define the StartDate and EndDate using a Basis of 0.

```yearFraction = yearfrac(' 14 mar 03', '14 sep 03', 0)
```
```yearFraction =

0.5027

```

There are 184 days between March 14 and September 14, and the calendar year after the StartDate is a leap year, so yearfrac returns 184/366 = 0.5027.