OpenChainGraph Suite · ART-332 · US Mortgage Compliance

Amortization Schedule Builder

Builds a full period-by-period amortization schedule for level-payment, adjustable-rate (index plus margin, caps, recast), interest-only, balloon, and temporary buydown (2-1 or 3-2-1) loans, following the unit-period and odd-days conventions in 12 CFR 1026 Appendix J. The output feeds directly into the Reg Z Appendix J APR Solver as its advances/payments input.

Reg Z Appendix J Level Payment / ARM / IO / Balloon / Buydown Cents-Integer Math Feeds APR Solver

🔒 All inputs are processed locally in your browser. No data is transmitted. Do not enter real personal data — use synthetic or anonymised inputs only.

Schedule parameters

Schedule type

Loan amount ($)

Note rate (annual %)

Initial/fixed rate for level_payment, ARM, IO, balloon, and the full note rate a temp_buydown eventually pays.

Number of payments

Periods per year

Payment override ($, level_payment only)

Leave blank to auto-compute the level payment via the standard annuity formula.

Odd days (App J unit-period)

Unit period days

Interest-only

IO periods

Balloon

Nominal amortization periods

Payment is computed on this longer term; the note matures at Number of payments above.

ARM: index, margin, caps, resets

Margin (%)

Periodic cap (+/- pts)

Lifetime cap (+pts vs initial)

Lifetime floor (pts vs initial, negative)

Recast at each reset

Rate changes (period_index:index_value_pct, one per line)

No live index fetching — supply the resolved index value your contractual lookback observed at each reset.

Temporary buydown

Buydown type

Schedule summary

Schedule (first 6 / last 3 periods)

#	t (periods)	Payment	Principal	Interest	Ending balance

Advances / payments (feeds ART-215)

advances[]1 entry: loan amount at t=0

payments[]

Totals and digest

Execution Hash (SHA-256)