Working notes
The arithmetic behind the calculators, worked out in public. Every number on these pages is computed at build time by the same code the tools run, so the tests that guard the calculators guard the writing too.
These are not guides. A guide answers a question that does not change — what a sinking fund is, how many paychecks are in a year. A note here carries a date and a table: something it would be dishonest to present as timeless, like which months of a specific year hold a third paycheck.
February can hold three paydays in 2028
A 28-day February cannot fit three biweekly paydays: the third lands on the 29th. In a leap year one schedule gets it. All fourteen 2028 cycles, with dates.
Read itWhen the extra paycheck lands in 2027
A biweekly year holds 26 paydays but only 24 two-payday slots, so two months get a third one. All fourteen possible 2027 schedules, with the dates.
Read itA printable envelope chart hides the only hard part
Charts stop at the total. $347 is 8 bills as one lump and 26 once it is split five ways, and the second number is the one you have to hand a teller.
Read it