Savings annuity calculator with graph help

 Settings Remark Days in year The number of days within a year can be set to: 366 days This is a leap year (normal year + 1 day extra (29 feb) 365 days Normal year (non leap year) 364 days The 364 day year derives from 52 weeks * 7 day weeks = 364 days in a year. 360 days When a month has 30 days, a year has 12 months * 30 = 360 days The nominal interest rate (R) is specified per year. The number of days within a year is important when adjusting the time period especially when the day unit is used. Example 1: How time period will be adjusted, a year has 366 days: Interest rate = 5% per year Time period = 100 days 366 days equals 1 year Thus 100 days equals 100/366 = 0.273224 days Example 2: How time period will be adjusted, a year has 365 days: Interest rate = 5% per day Time period = 100 days 365 days equals 1 year Thus 100 days equals 100/365 = 0.273973 days Example 3: How time period will be adjusted, a year has 364 days: Interest rate = 5% per day Time period = 100 days 364 days equals 1 year Thus 100 days equals 100/364 = 0.274725 days Example 4: How time period will be adjusted, a year has 360 days: Interest rate = 5% per day Time period = 100 days 360 days equals 1 year Thus 100 days equals 100/360 = 0.277778 days