Fix amortization float rounding leaving non-zero final balance #21

New Issue

tonym · 2026-06-06T19:58:13Z

tonym commented

2026-06-06 19:58:13 +00:00

Severity: medium
Category: correctness
Location: mortgage.py:51-55

Problem

Per-row round() over 360 months accumulates ~$3-5 error; the final schedule row shows a small non-zero balance so the loan looks unpaid at term.

Suggested fix

Track raw floats internally, round at display only, and append a final corrective payment if balance>0.

Filed by automated code review.

**Severity:** medium **Category:** correctness **Location:** `mortgage.py:51-55` ### Problem Per-row round() over 360 months accumulates ~$3-5 error; the final schedule row shows a small non-zero balance so the loan looks unpaid at term. ### Suggested fix Track raw floats internally, round at display only, and append a final corrective payment if balance>0. _Filed by automated code review._

tonym added the

correctness

severity:medium

labels 2026-06-06 19:58:13 +00:00

Sign in to join this conversation.

1 Participants

Notifications

Due Date

No due date set.

Dependencies

No dependencies set.

Reference: bonna61/Moon-Household-Budget#21