Methodology
Method last reviewed August 23, 2026
Direct answer
The opening balance, expected income, recurring bills, debt payments, subscriptions, and observed everyday spending. Known events keep their dates and exact amounts; uncertain spending becomes a range of complete 30-day paths.
Five stages
Each stage has a narrow job and a fail-closed boundary.
Shelter begins with connected balances and posted transactions. It does not invent a balance when the source is missing, stale, internally inconsistent, or in a different currency.
Expected income, recurring bills, debt payments, and subscriptions are represented on the date they are expected to post. Exact stored amounts stay in minor currency units so repeated calculations do not introduce rounding drift.
Everyday spending is not a single fixed number. Shelter resamples contiguous blocks of observed spending to create 200 reproducible paths through the forecast window. Keeping spending in blocks preserves the way real spending clusters across days.
Shelter accumulates the opening balance, dated income, commitments, and everyday spending day by day. It then reads lower, middle, and upper outcomes from complete balance paths rather than adding unrelated daily percentiles together.
The result is stored with its source versions, calculation policy, currency, cutoff time, and checksum. Product surfaces read that published record instead of quietly rebuilding different numbers for each screen.
Fail closed
Unavailable is safer than a confident answer built from broken money data.
Limits
Unexpected purchases and transfers can change the path immediately.
Income can arrive late or for a different amount. A biller can move a posting date.
A disconnected institution can make the account picture incomplete.
Thirty days is a short-term planning window, not a promise about long-term solvency.
Common questions
No. It is an estimate based on the connected data available at the forecast cutoff. New purchases, delayed income, changed bill dates, missing accounts, and bank-sync interruptions can change the result. Confirm the current balance with your bank before making a payment.
Bills and posted balances can be exact, but everyday spending is uncertain. Multiple whole-window spending paths make that uncertainty visible instead of hiding it inside one overconfident line.
Shelter suppresses forecast-dependent money guidance and explains that the forecast is unavailable. Missing amounts, incompatible currencies, stale source versions, and failed reconciliation are not treated as zero.
Published forecasts are scored against later balance snapshots. A calibration can move only when a windowed, directionally consistent signal is strong enough, and changing it requires a new canonical forecast before guidance resumes.
Read the security boundaries, try the manual safe-before-payday worksheet, or see how the connected forecasting product applies the same timing logic automatically.
