Joni Budget Calculator
Where the number comes from
| Line (colors match the ledger chart) | Baseline | With headroom | Basis |
|---|---|---|---|
| Dorm, single room | fixed — single room since July | ||
| eSIM · Sakura Mobile | fixed | ||
| Eating out | median Apr–Aug | ||
| Groceries / konbini | median Apr–Aug | ||
| Shopping | median Apr–Aug | ||
| Entertainment | median Apr–Aug | ||
| Other (bills, care, trips) | median Apr–Aug | ||
| Cash food | slider — Joni's call |
The honest finding behind this page: card spending has been on budget all along (≈¥90K/month vs ≈¥89K planned), and once the dorm is priced at its single-room cost of ¥85,000, July and August land under the re-based cap too. The cash number is the only line still set by promise rather than measurement.
The deal that makes it stick
1. Cash is rent first. The room can only be paid in cash, so the first ¥85,000 withdrawn each month is rent by definition and everything beyond it is the cash-food line. No guessing, no asking — the ledger reads it off the withdrawals.
2. Joni sets the sliders. A budget chosen is kept far more often than a budget assigned. Agree the number together on this page, then it's his number.
3. Weekly funding, weekly food rule. A quarter of the budget every Monday. A blown week costs one lean week — not a blown month and a bailout.
4. Under budget = Joni keeps it. Whatever's left at month-end rolls into a trip fund. Overshoot has been refunded until now — that rewards overshooting. Flip the incentive.