Calculator Index
Browse all 270 free calculators by category or from A to Z.
Biology Calculators
Punnett Square Probability Calculator
Estimate genotype and phenotype probabilities for a simple single-gene inheritance cross.
Hardy-Weinberg Equilibrium Calculator
Calculate expected allele and genotype frequencies under Hardy-Weinberg equilibrium.
Allele Frequency Calculator
Calculate allele frequencies from observed genotype counts.
Genotype Frequency Calculator
Calculate observed genotype frequencies from population counts.
DNA Base-Pair Percentage Calculator
Calculate DNA nucleotide percentages using counts of A, T, G, and C bases.
DNA Molecular Weight Calculator
Estimate DNA molecular weight from the number of base pairs or nucleotides.
DNA Dilution Calculator
Calculate stock DNA volume and diluent volume using C1V1 = C2V2.
PCR Master Mix Calculator
Scale reagent volumes for multiple PCR reactions with optional extra volume.
PCR Annealing Temperature Calculator
Estimate primer melting temperature and a starting PCR annealing temperature.
Cell Doubling Time Calculator
Calculate population doubling time from starting count, ending count, and elapsed time.
Bacterial Growth Calculator
Estimate bacterial population after a given number of generations.
Colony-Forming Units Calculator
Estimate colony-forming units per milliliter from plate count, dilution, and plated volume.
Microscope Magnification Calculator
Calculate total microscope magnification from eyepiece and objective lenses.
Hemocytometer Cell Count Calculator
Estimate cells per milliliter from hemocytometer counts and dilution factor.
Solution Dilution Calculator
Calculate the unknown value in a standard C1V1 = C2V2 dilution.
Molarity Calculator
Calculate solution molarity from moles of solute and solution volume.
Serial Dilution Calculator
Calculate final concentration after repeated equal dilution steps.
Population Growth Calculator
Estimate future population using exponential growth.
Biodiversity Index Calculator
Calculate Simpson's Diversity Index from species counts.
Predator-Prey Population Estimate Calculator
Estimate one-step predator and prey population changes using a simplified Lotka-Volterra model.
Games, Lotto & Casino Calculators
Lottery Odds Calculator
Calculate the jackpot odds for choosing numbers from a larger lottery pool.
Lottery Ticket Cost Calculator
Estimate the cost of buying lottery tickets over time.
Lottery Prize Split Calculator
Divide a lottery prize among multiple winners after an optional tax estimate.
Raffle Odds Calculator
Calculate your probability of winning one or more prizes in a raffle.
Keno Match Odds Calculator
Estimate the probability of matching a chosen number of spots in a generic keno drawing.
Bingo Card Probability Calculator
Estimate the chance that all required numbers on a simple bingo pattern have been called.
Coin Toss Probability Calculator
Calculate the probability of getting an exact number of heads in repeated fair coin tosses.
Dice Roll Probability Calculator
Calculate the probability of rolling a target value on one die over multiple rolls.
Two-Dice Total Calculator
Calculate the probability of a specific total when rolling two standard dice.
Craps Pass Line Odds Calculator
Show the standard probability and house edge for a basic craps pass line wager.
Roulette Odds Calculator
Compare the probability and payout for common American or European roulette bets.
Blackjack Hand Value Calculator
Total a blackjack hand while treating aces as 1 or 11 as appropriate.
Blackjack Bust Probability Calculator
Estimate the chance of busting on the next card using a simplified infinite-deck model.
Baccarat Hand Value Calculator
Calculate baccarat hand values using the ones digit of the card total.
Poker Hand Odds Calculator
Estimate the chance of completing a drawing hand from known outs and unseen cards.
Video Poker Draw Odds Calculator
Estimate the probability of hitting at least one desired card when drawing replacements.
Slot Machine RTP Calculator
Estimate expected return and expected loss from a slot machine RTP percentage.
Casino House Edge Calculator
Calculate expected casino advantage and player return from a house-edge percentage.
Expected Gambling Loss Calculator
Estimate long-run expected loss from average wager, number of bets, and house edge.
Parlay Odds Calculator
Combine independent decimal odds to estimate a parlay payout and implied probability.
Statistics Calculators
Mean Calculator
Calculate the arithmetic mean, count, sum, minimum, and maximum of a dataset.
Median Calculator
Find the median and middle position of an ordered dataset.
Mode Calculator
Find the most frequently occurring value or values in a dataset.
Range Calculator
Calculate the range, minimum, maximum, and midrange of a dataset.
Variance Calculator
Calculate population and sample variance from a dataset.
Standard Deviation Calculator
Calculate population and sample standard deviation from a dataset.
Standard Error Calculator
Calculate the standard error of the mean from sample standard deviation and sample size.
Z-Score Calculator
Calculate how many standard deviations a value lies above or below the mean.
Percentile Calculator
Estimate a percentile value from an ordered dataset using linear interpolation.
Quartile Calculator
Calculate the first quartile, median, and third quartile of a dataset.
Interquartile Range Calculator
Calculate Q1, Q3, the interquartile range, and common outlier fences.
Correlation Coefficient Calculator
Calculate Pearson's correlation coefficient for paired x and y values.
Linear Regression Calculator
Fit a least-squares line to paired x and y data.
Confidence Interval Calculator
Calculate a normal-approximation confidence interval for a population mean.
Sample Size Calculator
Estimate a sample size for a population proportion using confidence level and margin of error.
Chi-Square Calculator
Calculate a chi-square goodness-of-fit statistic from observed and expected counts.
t-Test Calculator
Calculate a two-sample Welch t statistic from summary statistics.
Normal Distribution Calculator
Estimate the cumulative probability below a value in a normal distribution.
Binomial Distribution Calculator
Calculate the probability of exactly k successes in n independent trials.
Probability Distribution Calculator
Calculate the expected value and variance of a discrete probability distribution.
Advanced Finance Calculators
Mortgage Extra Payment Calculator
Estimate interest savings and payoff time when adding extra monthly mortgage payments.
Biweekly Mortgage Payment Calculator
Compare standard monthly mortgage payments with a biweekly payment schedule.
Mortgage Points Calculator
Estimate the upfront cost of mortgage discount points and the break-even period.
Mortgage Closing Cost Calculator
Estimate total mortgage closing costs from percentage-based and fixed fees.
Home Affordability Calculator
Estimate an affordable home price from income, debts, down payment, rate, and housing-cost assumptions.
Rent vs. Buy Calculator
Compare simplified five-year housing costs for renting versus buying.
Auto Loan Extra Payment Calculator
Estimate payoff acceleration and interest savings from extra auto-loan payments.
Auto Loan Trade-In Calculator
Calculate the amount financed after trade-in value, payoff, taxes, fees, and down payment.
Personal Loan Comparison Calculator
Compare monthly payment and total interest for two personal-loan offers.
Debt Snowball Calculator
Estimate payoff order using the debt snowball method, from smallest balance to largest.
Debt Avalanche Calculator
Estimate payoff order using the debt avalanche method, from highest interest rate to lowest.
Balance Transfer Calculator
Compare a promotional balance transfer with keeping debt on the current card.
Credit Utilization Calculator
Calculate credit utilization across one or more revolving accounts.
Certificate of Deposit Calculator
Estimate certificate-of-deposit growth from principal, APY, term, and compounding frequency.
Bond Yield Calculator
Estimate current yield and approximate yield to maturity for a coupon bond.
Dividend Reinvestment Calculator
Estimate portfolio growth when dividends are reinvested.
Dollar-Cost Averaging Calculator
Estimate shares accumulated and average cost from repeated investments at changing prices.
Capital Gains Tax Estimate Calculator
Estimate taxable capital gain and tax using a user-provided tax rate.
Investment Fee Calculator
Estimate the long-term effect of annual investment fees on portfolio growth.
Required Minimum Distribution Calculator
Estimate a required minimum distribution using an entered prior-year balance and life-expectancy factor.
Retirement & Wealth Calculators
Net Worth Growth Forecast Calculator
Project future net worth from current assets, liabilities, annual savings, growth, and debt reduction.
FIRE Calculator
Estimate the portfolio target and time needed to reach financial independence.
Coast FIRE Calculator
Estimate whether current retirement savings can grow to a future target without additional contributions.
Barista FIRE Calculator
Estimate the investment portfolio needed when part-time income covers part of annual expenses.
Safe Withdrawal Rate Calculator
Estimate annual and monthly withdrawals from a portfolio using a chosen withdrawal rate.
Retirement Income Gap Calculator
Compare desired retirement income with expected Social Security, pension, and other income.
401(k) Employer Match Calculator
Estimate employee contributions, employer match, and total annual retirement contributions.
Roth vs. Traditional IRA Calculator
Compare simplified after-tax future values of Roth and Traditional IRA contributions.
Roth Conversion Calculator
Estimate taxes due on a Roth conversion and the future after-tax comparison.
Pension Lump Sum vs. Annuity Calculator
Compare a pension lump sum with the present value of lifetime monthly payments.
Social Security Break-Even Calculator
Estimate the age when delaying Social Security may produce more cumulative benefits.
529 College Savings Calculator
Project a 529 college-savings balance from current savings and monthly contributions.
College Cost Projection Calculator
Estimate future college costs after tuition inflation.
Annuity Payout Calculator
Estimate a level monthly payout from a fixed principal over a chosen period.
Annuity Present Value Calculator
Calculate the present value of equal future payments.
Inflation-Adjusted Return Calculator
Convert a nominal investment return into an inflation-adjusted real return.
Real Rate of Return Calculator
Calculate real return after inflation and estimated taxes.
Portfolio Withdrawal Calculator
Estimate how long a portfolio may last with regular withdrawals and investment growth.
Financial Independence Date Calculator
Estimate the calendar year when investments may reach a financial-independence target.
Lifetime Wealth Projection Calculator
Project long-term wealth from savings, returns, major withdrawals, and years invested.
Real Estate Investing Calculators
Cap Rate Calculator
Calculate a property's capitalization rate from annual net operating income and property value.
Cash-on-Cash Return Calculator
Estimate annual cash-on-cash return from pre-tax cash flow and total cash invested.
Net Operating Income Calculator
Calculate net operating income from gross rental income, other income, vacancy, and operating expenses.
Debt Service Coverage Ratio Calculator
Calculate debt service coverage ratio from annual net operating income and annual debt payments.
Gross Rent Multiplier Calculator
Calculate gross rent multiplier from property price and annual gross rental income.
Rental Cash Flow Calculator
Estimate monthly and annual rental property cash flow after operating expenses and debt service.
Rental Property ROI Calculator
Estimate total annual return on a rental property from cash flow, principal paydown, and appreciation.
Property Appreciation Calculator
Project a property's future value using an annual appreciation rate.
Rent Increase Calculator
Calculate a new rent amount from a percentage or dollar increase.
Vacancy Loss Calculator
Estimate annual vacancy loss from monthly rent, number of units, and vacancy rate.
Repair Budget Calculator
Estimate a property repair budget from individual project costs, contingency, and carrying costs.
House Flip Profit Calculator
Estimate house-flip profit after purchase, renovation, financing, holding, and selling costs.
BRRRR Investment Calculator
Estimate cash left in a BRRRR deal after renovation and refinance.
Seller Financing Calculator
Calculate payment and total interest for a seller-financed property purchase.
Land Contract Calculator
Estimate monthly payment, balloon balance, and interest for a land contract.
Commercial Loan Calculator
Estimate monthly payment and balloon balance for a commercial real estate loan.
Rental Property Break-Even Calculator
Estimate the monthly rent needed to cover operating expenses, vacancy, and debt service.
Equity Growth Calculator
Project real estate equity from appreciation and mortgage principal reduction.
Closing Cost Comparison Calculator
Compare two real estate closing-cost estimates and determine the lower-cost option.
Rent vs. Mortgage Investment Calculator
Compare monthly rent income with mortgage and operating costs for a rental investment.