Calculator methodology
Every number has a method.
Here is exactly what the calculators do—and what remains outside the model.
Growth projection
Let P be starting value, C the end-of-month addition, r the effective annual growth assumption, f the annual value-based fee fraction, and N the number of years. The monthly growth factor is (1+r)1/12; the monthly fee factor is (1−f)1/12. Each month: next value = previous value × growth factor × fee factor + C.
The effective annual rate after the modeled fee is (1+r)(1−f)−1. Today’s-dollar value divides each year-end balance by (1+inflation)year. Fees on a benefit base, premium bonuses, indexed crediting, rate renewals, taxes, surrender charges and market value adjustments are not modeled. Not all contracts accept later contributions.
Income gap and fixed-period drawdown
Starting spending and existing income are monthly amounts at the start of the modeled period. Each increases once per year at its entered rate. Monthly gap = max(0, monthly spending − existing monthly income). The modeled reserve is the sum of each monthly gap discounted to the start at the constant net return assumption.
For a separate level drawdown, monthly return i = (1+r)1/12−1 and n = years × 12. The payment is P × i / [1−(1+i)−n]. At a zero return it is P/n. Payments occur at month-end and exhaust the modeled balance at the end of the selected period. This is not insurer pricing, a sustainable-withdrawal estimate or a lifetime promise. Inflation does not increase this separate fixed-payment result.
Written quote comparison
Starting monthly payment = premium × entered annual payout percentage / 12. Payments increase annually by the entered adjustment. Cumulative payments add every scheduled payment through the selected year. Purchasing-power results divide payments by (1+inflation)year−1. The comparison assumes all payments occur; it does not model death, survivor changes, refunds, surrender values, fees, tax or probability.
Use the same premium, start date and payment protections for both quotes. A payout percentage includes return of capital; it is not an interest rate or internal rate of return. Defaults are examples. No carrier rate feed is connected.
Index crediting example
This simplified one-year model uses credit = max(0, min(cap, index change × participation − spread)). It then applies the entered account-value fee to the post-credit value. Actual contracts can use different measurement periods, crediting methods, fee bases and ordering. This example is neither a carrier illustration nor a registered index-linked annuity model. A zero interest credit can still produce a negative net value change when fees apply.
Model boundaries
All four tools are deterministic. They do not simulate market sequences, mortality, changing tax law or an insurer’s solvency. Whole-year horizons range from 1 to 50. Results round for display; calculations use unrounded values. Explore different assumptions rather than treating one scenario as a forecast.
Privacy and saved scenarios
Calculator values are processed locally in your browser. Saving downloads a JSON file to your device; loading reads a selected file locally. CSV exports include inputs and results. The site does not transmit these values to a CRM or advertising system. Keep downloaded files private if they contain your personal financial assumptions.