Finance Calculator Guide: Every Financial Tool on Apex Conversion

The Compound Interest Calculator is the most fundamental finance tool on the site. Enter a principal amount, annual interest rate, time period, and compounding frequency to see how a lump-sum investment grows. It also supports monthly contributions, making it suitable for modeling retirement savings, college funds, or any regular investment plan. For background, see How Compound Interest Works and Compound vs Simple Interest.

The CAGR Calculator (Compound Annual Growth Rate) solves the inverse problem: given a starting value and ending value over a known period, what was the annual growth rate? This is essential for evaluating investment performance, comparing portfolio returns to benchmarks, or analyzing business revenue growth. The Finance Formula Handbook covers the underlying CAGR formula and related concepts.

The Mortgage Calculator computes your monthly payment, total interest paid over the life of the loan, and total repayment amount from four inputs: home price, down payment, interest rate, and loan term (15 or 30 years). It is the fastest way to assess affordability and compare scenarios. The Amortization Schedule goes deeper: it generates a full payment-by-payment breakdown showing exactly how much of each payment goes to principal vs interest throughout the loan.

The Loan Calculator handles any loan type — auto, personal, student — with the same logic as the mortgage tool but without the home-specific parameters. For background on mortgage math: Mortgage Payment Formula explains the amortization formula, and How Loan Interest Works covers interest calculation mechanics. APR vs APY explains why the mortgage APR (which includes fees) differs from the stated interest rate.

The Savings Calculator projects a savings account balance over time, given a starting balance, monthly contribution, and APY (Annual Percentage Yield). It shows how regular contributions combined with compound interest grow a balance — the Savings Calculator Guide explains how to use it effectively for specific financial goals. The Retirement Calculator adds employer match functionality and projects a retirement balance from current age through retirement age.

For planning context: the Retirement Calculator Guide covers contribution strategies, 401(k) vs IRA considerations, and safe withdrawal rules. The Inflation Calculator shows how inflation erodes purchasing power over time — projecting how much a future sum is worth in today's dollars, or how much you will need to maintain purchasing power.

Beyond calculators, the site has a growing library of finance articles that explain the concepts behind the tools. How Compound Interest Works: the mathematics of exponential growth, compounding frequency, and the power of time. Compound vs Simple Interest: why compound interest grows so much faster over long periods. Rule of 72 Explained: the mental math shortcut for estimating investment doubling time.

APR vs APY: why the stated interest rate and true annual yield differ, and when each matters. Future Value vs Present Value: the time value of money, discounting, and how to evaluate any cash flow across time. Finance Formula Handbook: a reference page for the exact formulas behind compound interest, mortgage payments, CAGR, NPV, and more.

For current contribution limits, tax data, and historical inflation figures, the References section provides regularly updated tables. The Finance Reference Center includes retirement contribution limits (401k, IRA, Roth IRA), HSA limits, tax brackets for current and prior years, and historical US inflation rates.

Use these reference tables alongside the calculators: enter current 401(k) limits into the Retirement Calculator to model maximum-contribution scenarios; use historical inflation rates with the Inflation Calculator to see how your purchasing power has changed over specific time periods.