Offset Ledger / daily-record workbench
Account for
every day.
An interest charge is a month of small calculations. Put the balances beside the bill and follow the money, one day at a time.
Timing matters.
The same opening and closing offset balances can hide very different months. Try the invented example below.
What this model can establish ↗This checks your records against an explicit model. It has not been validated against a complete real lender statement. A mismatch is a question to investigate, not proof of a bank error.
Invented example
Thirty days. Two rounding models.
Preparing the example…
Inputs changed. Reconcile again to see and export the updated result.
The reconciliation
Difference = supplied charge minus model charge. A value between two model totals can still match neither. Zero difference establishes arithmetic consistency only.
What the offset changes in this model
The no-offset comparison keeps your supplied loan balances fixed. It does not simulate the loan's alternative history, measure actual savings or calculate compensation.
Follow the month
See where interest accumulates.
Daily model amounts before rounding. The ledger below gives exact fractions; chart heights are approximate.
The daily ledger
Nothing between the rows.
| Date | Loan | Eligible offset | Rate % | Interest rounded daily |
|---|
Daily-rounded values are one hypothesis. Adding these displayed cents does not reproduce the period-end rounding model.
Take the evidence
A report you can reopen.
Includes all normalized daily records, your declarations, exact calculations and rounding comparisons. Downloads contain your financial data.
Verify it independently, offline
Download the standalone Python checker ZIP, extract it beside your report, and run:
python3 check_report.py offset-report.json
Python 3, standard library only. The checker recalculates every day without our JavaScript engine or a network connection. It checks arithmetic and internal consistency. It cannot authenticate bank records, declarations or offset linkage. Method and file format.
Reopen a saved report.
Recalculates the report before loading it. A valid file can still contain incorrect source data or declarations. The separate Python checker gives an independent calculation.
Bring a precise question to the lender.
If a charge differs, first confirm the accrual dates, interest-effective balances, rate changes, linked offsets, rounding and adjustments. This workbench does not discover which of those is wrong. A matching total also cannot prove an offset was linked correctly every day.
This version accepts complete daily records for one variable-rate loan split and fully eligible offsets. It does not reconstruct a bank transaction export, read PDFs, guess missing days, handle partial offsets or support a specific lender's statement format.
Record parsing and calculations run in your browser. This tool does not upload your inputs, put them in URLs or save them to browser storage. Closing or reloading the page clears them unless you download a report.
Calculation, sources and validation limits · More practical tools