Financial Scenario Planner

For fixed payment loans (annuity method), the standard amortization formula is used: M = P * [r(1+r)^n] / [(1+r)^n - 1], where P is principal, r is the periodic interest rate (annual rate divided by payments per year), and n is total scheduled periods. When the interest rate is 0%, the payment is simply principal divided by term (P / n).

Under fixed payment (annuity / 元利均等), the total periodic payment remains constant while the interest portion decreases and the principal portion increases over time. Under declining principal (equal principal / 元金均等), a fixed amount of principal is repaid each period, meaning initial monthly payments are higher and gradually decrease over time.

Yes. The calculation engine explicitly handles 0% interest rates as a distinct mathematical edge case, dividing principal evenly across periods without producing NaN or division-by-zero errors.

The schedule provides a complete periodic breakdown including payment number, payment date, scheduled payment, principal portion, interest portion, recurring fees, extra prepayment applied, total paid, and remaining loan balance, as well as aggregated yearly summaries.

Extra monthly payments are applied directly to principal reduction. By reducing the outstanding balance faster, subsequent interest charges are lower, accelerating total loan payoff and reducing the overall duration and interest cost.

Yes. You can add multiple one-time lump sum prepayments at specific payment periods or dates (for example, applying an annual bonus or tax refund). These are allocated directly to reducing the remaining principal balance.

You can define custom interest rate steps that take effect at specific period numbers (e.g., 2.0% for the first 5 years, then 3.5% thereafter). The planner recalculates subsequent monthly payments based on the remaining balance and term.

No. The tool strictly adheres to objective mathematical modeling. It presents exact differences in cost, duration, and balances, but never scores, ranks, or declares a 'winner' scenario.

Cash Flow Mode projects opening balance, recurring income, recurring expenses, and one-time financial events across a specified monthly horizon, tracking net cash flow, ending balances, and potential cash deficits.

You can specify assumed annual percentage growth for income and expenses, as well as a general inflation rate. The simulation displays both nominal projected balances and inflation-adjusted purchasing power.

The simulation flags any period where the closing balance dips below zero with an objective warning ('Cash balance becomes negative in period X'), and also alerts you if the balance drops below your desired minimum reserve.

Given an initial amount, ongoing contributions, and an expected annual return assumption, it calculates compound growth across your chosen compounding frequency (monthly, quarterly, or yearly) and projects when your target will be achieved.

Yes. By specifying a target completion date, the reverse calculation engine computes the exact regular monthly contribution required to reach your target balance by that deadline.

No. Expected returns and compounding rates are entered entirely by the user. Solasu does not recommend stocks, ETFs, mutual funds, crypto, or any financial products.

Yes. All exported cells starting with dangerous characters (=, +, -, @, tab, carriage return) are sanitized with a prepended single quote in accordance with spreadsheet security standards.

You can export all active scenarios into a structured JSON file and reload them at any time. The JSON parser includes prototype pollution defenses against malicious object manipulation.

The generated PDF includes scenario assumptions, key summary metrics, comparison tables, and schedule summaries rendered using True Unicode vector fonts. Generated PDFs are re-verified using PDF.js to ensure structural integrity.

Never. Solasu operates 100% locally in your browser memory. No loan amounts, interest rates, incomes, expenses, balances, or scenario names are ever sent across the network.

No. To ensure maximum financial privacy, no data is stored in cookies, localStorage, sessionStorage, or IndexedDB. If you want to keep your work, download it via the JSON Export feature.

Commercial lenders may employ specific daily interest accrual conventions (e.g., 30/360 or Actual/365), holiday payment date shifts, proprietary rounding rules, or specific prepayment penalties that differ from standard amortization models.

Yes. The interface is responsive down to 375px mobile screens, with accessible SVG charts, full keyboard navigation, and tabbed panels optimized for both desktop and touchscreens.