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Finance calculators

Calculators for growing savings, planning retirement, adjusting for inflation and solving time value of money problems, plus a portfolio standard deviation calculator for investment risk. They suit savers checking a plan and students working through a finance course.

Which calculator do I need?

You have or wantUse
A lump sum and an interest rate, and want the balance after some yearsCompound interest calculator
Regular monthly contributions, and want the end balance or the contribution a target needsInvestment calculator
Current savings and a retirement age, and want to know how long the money lastsRetirement calculator
A price today, and want its cost in the future or the value of past moneyInflation calculator
Four of N, I/Y, PV, PMT and FV, and want the fifthFinance calculator (TVM)
A series of cash flows, and want NPV, IRR or the payback periodFinancial mathematics calculator
Asset weights, volatilities and correlations, and want the portfolio’s riskPortfolio standard deviation calculator

Saving and investing

See how a lump sum or regular deposits grow with compound interest.

Planning for the future

Check whether savings will cover retirement and what inflation does to their value.

Time value of money and risk

Solve textbook TVM problems, value cash flows, and measure the volatility of a portfolio.

One formula behind most of these calculators

Compound growth, FV = PV × (1 + r)ⁿ, sits under nearly every calculator here. The compound interest calculator applies it to a lump sum; the investment calculator adds regular contributions (an annuity); the retirement calculator runs it forwards to retirement and then draws the balance down; and the inflation calculator uses the same formula with the inflation rate to move prices through time. The finance calculator solves the general time value of money equation for any one of N, I/Y, PV, PMT or FV, as a BA II Plus would. The financial mathematics calculator extends this to uneven cash flows, NPV and IRR.

Worked comparison: how compounding frequency matters

Put $10,000 away at 6% a year for 10 years:

CompoundingBalance after 10 years
Yearly$17,908.48
Monthly$18,193.97
Continuous$18,221.19

Monthly compounding adds about $285 over yearly, and continuous compounding only another $27. The rate matters far more than the frequency. With 3% inflation, the monthly-compounded $18,193.97 is worth about $13,538 in today’s money, since prices rise by a factor of 1.03¹⁰ = 1.344.

Common mix-ups

  • Nominal rate vs APY. 6% compounded monthly is an effective annual yield of 6.17%. Compare accounts on APY.
  • Sign convention in TVM. Money you pay out is negative and money you receive is positive; entering PV and FV with the same sign usually gives no solution.
  • Nominal vs real returns. A 7% return with 3% inflation grows purchasing power by about 3.9% a year, not 7%.
  • Portfolio risk is not the average of the risks. Unless assets are perfectly correlated, the portfolio standard deviation is lower than the weighted average of the individual SDs.

Guides to read alongside

Common questions

What is the difference between the compound interest and investment calculators?
The compound interest calculator focuses on a single deposit and can solve for the rate, time or starting amount. The investment calculator is built around regular contributions and can find the monthly amount needed to reach a target.
Do these calculators account for tax and fees?
Not directly. Subtract annual fees from the return rate, and use an after-tax rate if returns are taxed each year, to get a closer estimate.
What does the rule of 72 tell me?
Divide 72 by the annual percentage rate to estimate the years it takes money to double. At 6% that is 12 years; the exact figure with yearly compounding is 11.9 years.

Written and reviewed by our editorial team. Last updated . Method and sources: how these numbers are computed.