Plans & strategy

How surplus gets routed

The math-optimal split across three buckets in priority order: reserve, high-APR debt, then investing.

Given a period's free cash (income minus bills, caps, and goals), Keel computes a math-optimal split across three buckets, in priority order:

  1. Reserve. If cash is below 3 months of expenses, it tops up first. A thin cushion is the highest-priority risk to close.
  2. High-APR debt.Any debt whose APR beats your plan's expected return by at least 2 points (e.g. 7% expected → a 9% threshold) gets attacked, highest APR first. Paying it is a guaranteed return at that rate.
  3. Investing.Whatever's left flows to the plan's investment rule.

This is "invest the leftover" done properly: the tool isn't telling you how much to deposit — it's showing where your available surplus mathematically goes furthest, and you decide. The split (and its plain-English rationale) appears inside each prescription's "Why?" expander.

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