Investing

How to use the Investing calculators

Time value of money, compounding, bonds, funds, and project math.

There are 25 calculators in Investing. Each one has its own fields and its own formula. They are listed on this page so you can pick the question you actually have. Open the tool, replace the example, and press Calculate. The result stays in the browser.

Do not treat this index as a single worksheet. A payment, a payoff date, and a tax estimate answer different questions. Adding the headlines together mixes kinds of dollars. Read one result, then open the next tool if the question changed.

What each calculator is for

Finance Calculator — Solve future value, payment, rate, periods, or present value the way a five-key financial calculator does. The form includes N (# of periods), I/Y (Interest per year), PV (Present Value), PMT (Periodic Payment). FV, PMT, I/Y, N, and PV, with the sign convention shown.

Compound Interest Calculator — Project compound growth with regular contributions and a compounding frequency you choose. The form includes Starting amount, Contribution each period, Annual interest rate, Compounds per year. Interest that starts earning interest of its own.

Simple Interest Calculator — Calculate simple interest with I = P × r × t and the amount you would have at the end. The form includes Principal, Annual rate, Time in years. Interest that never earns interest of its own.

Interest Calculator — See the interest a starting balance and ongoing contributions earn at a compound rate. The form includes Initial investment, Annual contribution, Monthly contribution, Contribute at the. A direct answer to how much interest you earn.

Interest Rate Calculator — Solve the annual interest rate that links a present value, payment, future value, and number of periods. The form includes N, periods, Present value, Payment, Future value. The rate that makes the other four numbers true.

Investment Calculator — Project an investment from a starting balance, a monthly contribution, and an annual return. The form includes Starting balance, Monthly contribution, Expected annual return, Years. Starting balance plus a monthly contribution.

Savings Calculator — Grow a savings balance with monthly deposits and a compound annual rate. The form includes Current savings, Monthly deposit, Annual yield, Years. What a monthly deposit becomes.

Savings Goal Calculator — Find the monthly deposit that reaches a goal, counting what you have already saved. The form includes Goal, Already saved, Months, Annual yield. The deposit that hits a dated goal.

CD Calculator — Project a certificate of deposit from its APY and term in months. The form includes Deposit, APY, Term. APY in, value at maturity out.

Bond Calculator — Price a fixed coupon bond from face value, coupon, yield, and payment frequency. The form includes Face value, Coupon rate, Yield, Years to maturity. Price moves when the yield and the coupon disagree.

Mutual Fund Calculator — Grow a mutual fund balance after subtracting the expense ratio from the gross return. The form includes Starting balance, Monthly contribution, Gross annual return, Expense ratio. Gross return minus the expense ratio.

Average Return Calculator — Compare the simple average of yearly returns with the compound average that links them. The form includes Yearly returns, one percent per line. Simple average beside the compound average.

IRR Calculator — Find the internal rate of return for uneven cash flows, one period per line. The form includes Cash flows, time zero first. The rate that sets NPV to zero.

The rest of this set

ROI Calculator — Measure total and annualized return on investment from cost, amount returned, and years. The form includes Amount invested, Amount returned, Years. Total ROI and the annualized rate.

Payback Period Calculator — Find the payback period, the discounted payback, and the cash-flow return for a growing or uneven investment. The form includes Cash flow pattern, Initial investment, Cash flow per year, Yearly increase. Years to earn the cost back, with a discount rate.

Present Value Calculator — Discount a future amount and a payment stream back to a present value. The form includes Periods, Discount rate per year, Payment each period, Future value. What a future sum is worth today.

Future Value Calculator — Grow a present amount and a periodic payment forward to a future value. The form includes Periods, Interest per year, Present value, Payment each period. What today’s balance becomes.

CAGR Calculator — Calculate the compound annual growth rate between a beginning value and an ending value. The form includes Beginning value, Ending value, Years. One smooth rate between two values.

Rule of 72 Calculator — Estimate how long money takes to double, and compare the rule of 72 with the exact compound time. The form includes Solve for, Annual rate, Years. A mental estimate, checked against the exact time.

NPV Calculator — Discount a list of cash flows at a hurdle rate and read the net present value. The form includes Discount rate per period, Cash flows, time zero first. Cash flows discounted at the rate you require.

Dividend Calculator — Project dividend income and ending value, with or without reinvestment. The form includes Shares, Price per share, Dividend yield, Annual price growth. Yield, growth, and the choice to reinvest.

Stock Return Calculator — Combine price change and dividends into a total gain and an annualized return. The form includes Shares, Buy price, Sell price, Dividends received. Price gain plus the dividends you were paid.

Real Return Calculator — Convert a nominal return and an inflation rate into a real return. The form includes Nominal return, Inflation. The return that is left after inflation.

Perpetuity Calculator — Value a payment that continues forever and grows at a steady rate. The form includes Next payment, Discount rate, Growth of the payment. A forever payment, discounted once.

Inflation Calculator — Move an amount forward or backward in time at a constant inflation rate. The form includes Amount in today’s dollars, Annual inflation, Years, Direction. The same dollars, a different year.

What this category will not do

Investing pages on this desk are educational. They do not apply for a loan, file a return, or move money. Where a 2026 public figure is used, the methodology names the limit and the page says what it leaves out.

If a result looks wrong, check the field that does not match your paperwork before you blame the formula. A payment that includes tax and insurance will not match a quote that is principal and interest only. A contribution above a legal limit will still compound on this desk if you type it, which is why the retirement pages tell you to type only what you are allowed to add.

A session on this page

Pick one question in Investing and open only that calculator. Finance, Compound Interest, Simple Interest, Interest, Interest Rate, Investment, Savings, Savings Goal, CD, Bond, Mutual Fund, Average Return, IRR, ROI, Payback Period, Present Value, Future Value, CAGR, Rule of 72, NPV, Dividend, Stock Return, Real Return, Perpetuity, Inflation are the choices. Read the blurb under the name. If the blurb is not your question, go back and choose again. Running three tools “just in case” produces three headlines that were never meant to be added.

On the tool you chose, leave the example long enough to press Calculate once. You are checking that a result appears and that the labels match the story in the heading. Then replace every field. Time value of money, compounding, bonds, funds, and project math. The example numbers on each form are there so the formula can be demonstrated. They are not a suggestion that your price, payment, or income should look like the default.

Write down the headline and the two lines under it that you might quote later. If you cannot say which input produced them, you are not ready to use them. Change the input you are least sure about and press Calculate a second time. The size of the move tells you whether to go find a better source for that input before you decide.

After you press Calculate

Investing stays inside finance math. It does not collect an application and it does not rank products. When the result is an estimate of tax, a retirement limit, or a payment a lender could quote differently, the page says so. The disclaimer and the methodology apply to every link on this index, including Finance Calculator and Inflation Calculator.

In one line each, the set is: Finance Calculator (FV, PMT, I/Y, N, and PV, with the sign convention shown.); Compound Interest Calculator (Interest that starts earning interest of its own.); Simple Interest Calculator (Interest that never earns interest of its own.); Interest Calculator (A direct answer to how much interest you earn.); Interest Rate Calculator (The rate that makes the other four numbers true.); Investment Calculator (Starting balance plus a monthly contribution.); Savings Calculator (What a monthly deposit becomes.); Savings Goal Calculator (The deposit that hits a dated goal.); CD Calculator (APY in, value at maturity out.); Bond Calculator (Price moves when the yield and the coupon disagree.); Mutual Fund Calculator (Gross return minus the expense ratio.); Average Return Calculator (Simple average beside the compound average.); IRR Calculator (The rate that sets NPV to zero.); ROI Calculator (Total ROI and the annualized rate.); Payback Period Calculator (Years to earn the cost back, with a discount rate.); Present Value Calculator (What a future sum is worth today.); Future Value Calculator (What today’s balance becomes.); CAGR Calculator (One smooth rate between two values.); Rule of 72 Calculator (A mental estimate, checked against the exact time.); NPV Calculator (Cash flows discounted at the rate you require.); Dividend Calculator (Yield, growth, and the choice to reinvest.); Stock Return Calculator (Price gain plus the dividends you were paid.); Real Return Calculator (The return that is left after inflation.); Perpetuity Calculator (A forever payment, discounted once.); Inflation Calculator (The same dollars, a different year.). Open the one whose line matches the paper in front of you.

FAQs