Day-count conventions (30/360 · Actual/365 · Actual/360)

Pick how interest days are counted per loan, set an org-wide default in Settings, and understand what changing it does to the schedule.

Updated July 9, 2026

Different notes count interest days differently. NoteHarbor supports the three standard day-count conventions, per loan:

  • 30/360 (the default) — every month is 30 days, every year 360. The convention most seller-finance notes and standard amortization tables assume.
  • Actual/365 — actual days elapsed over a 365-day year.
  • Actual/360 — actual days elapsed over a 360-day year (common on commercial paper; yields slightly more interest per day).

Setting it

  • Per loan — choose the convention in the loan wizard's terms. Match whatever the signed note says.
  • Org default — set your organization's default under Settings; the wizard prefills it so your usual paper is one less thing to pick.

Changing it on an existing loan

The convention is a real term of the loan, so changing it is an audited term edit: it takes a note, and NoteHarbor regenerates the unpaid schedule under the new convention (paid rows are history and stay put).

If a migrated loan's interest is off by pennies per period, the day-count convention is the first thing to check against the original note.

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Day-count conventions (30/360 · Actual/365 · Actual/360) · NoteHarbor Help