Percentage & Rate Calculators
A hundred one-formula calculators — discounts, tax, interest, concentration
📐 Results update as you type, and every page shows the formula.
Price & Discount27
Discount CalculatorFind the final price and how much you save from a list price and a percentage off.Reverse DiscountWork out the percentage off when you only know the list price and the sale price.Stacked DiscountSee the true percentage off when a coupon is applied on top of an already reduced price.Fixed Coupon vs Percent OffCompare a flat-amount coupon against a percentage discount to see which saves more.Markup PricingSet a selling price by adding a markup percentage to your cost.Profit Margin CalculatorGet profit, margin on revenue, and markup on cost from a cost and a selling price.Price for Target MarginWork backwards from the margin you want to the price you need to charge.Break-Even UnitsHow many units you must sell to cover your fixed costs.Price per 100gCompare products of different sizes on the same per-unit basis.Price IncreaseApply a percentage increase and see the new price and the difference.Stacked Discount (3 Coupons)Find the real percentage off when three discounts pile up.Buy X Get Y FreeTurn a “buy two get one free” offer into a plain percentage off.Cost per UseDivide a big purchase by the number of times you will actually use it.Bundle vs SinglesCheck whether the multipack is actually cheaper than buying singles.Free Shipping Top-UpDecide whether adding to your basket beats paying for delivery.Paid Membership Break-EvenHow many uses it takes before the annual fee pays for itself.Currency Exchange SpreadSee how far the rate you were given sits from the mid-market rate.Resale Value DepreciationWhat something is worth after losing a fixed share of its value each year.Discount CeilingThe deepest discount you can give and still keep your target margin.Pay in Full vs Interest-Free InstalmentsCompare an upfront discount against spreading the cost for free.Price per KilogramDivide price by weight to compare packs of different sizes on the same footing.Real Price per Item with ShippingSpread the delivery fee across the items to see what each one really costs.Bulk Tier Price CalculatorTotal and true unit cost when the price drops at a quantity threshold.Split a Bill by UsageDivide a shared bill by how much each side actually used.Trade-In Discount CalculatorWhat a trade-in credit is really worth as a percentage off.Average Order Value Uplift CalculatorThe uplift a target AOV needs, and the revenue it adds at unchanged order volume.Lease vs Buy CalculatorTotal cost of leasing for a term against buying and reselling at the end.
Tax & Payout23
Add VATAdd VAT to a net amount to get the total you should invoice.Extract VATSplit a VAT-inclusive total into the net amount and the tax.Tip CalculatorAdd a tip to the bill and split it across the table.Split the BillDivide a total across people and round up to a convenient amount.Withholding TaxTake withholding tax off a freelance payment to see the net amount.Commission & PayoutSubtract a platform commission from your sales to see the actual payout.Effective Tax RateFrom gross and net pay, see what share was actually deducted.Gross-Up CalculatorWork out the contract amount needed to hit a target net payment.Add Sales Tax (Any Rate)Enter your own tax rate to get the price with tax added.Tax-Free to Taxable Equivalent YieldWhat a taxable product must pay to match a tax-free one.Service Charge Plus TaxWork out a hotel or restaurant bill where tax is charged on the service charge too.Two Fees StackedWhat lands in your account when a platform cut and tax are taken in turn.Pro-Rata RefundHow much comes back when you cancel part-way through a term.Import Landed CostThe real total once customs duty and consumption tax are added.Over the Duty-Free AllowanceTax on the part of your purchase that exceeds the allowance.Take-Home Hourly RateTurn a monthly salary, deduction rate and hours into a real hourly wage.Hourly Pay to MonthlySee monthly and yearly income from an hourly rate and the hours you work in a month.Price to Net a Target AmountWork back to the asking price when you know what you want left after commission.Crossing a Tax BracketWhat actually changes when income passes a bracket threshold.Straight-Line Depreciation CalculatorYearly and monthly depreciation plus the book value after n years, from cost, salvage and life.Freelance Hourly Rate CalculatorThe hourly rate a target yearly income needs, once non-billable time is counted.Salary vs Hourly Rate CalculatorTurn a salary plus benefits into the hourly rate that matches it at your billable hours.Real Return After Tax CalculatorStrip tax from a nominal return, then inflation, to see what purchasing power actually gained.
Percentage & Change51
Percent of a NumberFind what a given percentage of a value comes to.A is What Percent of BFind what share a part represents out of a whole.Percent ChangeFind the percentage increase or decrease between two values.Percentage DifferenceCompare two values relative to each other when neither is the baseline.Percentage Point vs PercentTell apart a 1-point rise and a 25% rise when a rate goes from 4% to 5%.Reverse PercentageRecover the original value when you only know the value after a change.Split by RatioDivide an amount in a ratio like 3:2 and see each share.Simplify a RatioReduce a ratio of two numbers to its smallest whole-number form.Proportion SolverSolve for the missing term in A : B = C : ?CAGR CalculatorConvert total growth over several years into one steady annual rate.Ratio to PercentageTurn a ratio like 7:3 into the percentage each side represents.Weighted Average RateCombine the rates of two groups of different sizes into one overall rate.Percentage of a PercentageWork out what 25% of 40% comes to as a share of the whole.Two Changes in a RowThe total change after something rises and then falls.Percent ErrorHow far a measurement strayed from the true value, as a percentage.Growth Rate NeededThe yearly growth required to hit a target within a set time.Top Percentage & PercentileTurn a rank out of a total into a top-x% and a percentile.Split Three Ways by RatioDivide an amount between three people in an agreed ratio.Per Mille (‰) & ppm ConverterSee a small share as a percentage, per mille and parts per million at once.Inverse Proportion (People × Days)How the schedule shrinks when you add people.Percentage RemainingSee what share is left and what share is gone.Rebase to an Index of 100Set a base period to 100 and express the current value as an index.Multiple to Percent IncreaseConvert a multiple into a percentage increase and back.Time to Halve CalculatorHow many years it takes to fall to half at a steady rate of decline.Price Elasticity of DemandHow much demand shifts for a given price change.Equity Dilution CalculatorHow much a new share issuance shrinks your ownership percentage.Population Growth Rate CalculatorAnnualized growth rate from a population at two points in time.Unemployment Rate CalculatorUnemployment rate from the unemployed count and labor force size.Cap Rate CalculatorReal-estate return from net operating income and purchase price.Dividend Payout Ratio CalculatorHow much of net income a company pays out as dividends.Debt-to-Equity Ratio CalculatorCompare total debt to shareholders' equity to see financial leverage.Current Ratio CalculatorCompare current assets to current liabilities to see short-term solvency.Interest Coverage Ratio CalculatorHow many times operating profit covers interest expense.Population Density CalculatorPeople per square kilometer, from population and area.Margin vs Markup CalculatorConvert between markup on cost and gross margin on revenue, in both directions.Target Profit Units CalculatorHow many units you must sell to reach the profit you want.Contribution Margin CalculatorContribution per unit, the contribution ratio, and the units it takes to cover fixed costs.Cross Rate CalculatorChain two quoted rates into the third-currency rate nobody quotes directly.ROAS CalculatorReturn on ad spend as a multiple and a percentage, against the break-even ROAS your margin implies.CPM, CPC and CTR CalculatorCPM, CPC and CTR from impressions, clicks and spend — and how CTR moves CPC at a fixed CPM.EBITDA Margin CalculatorEBITDA and the EBITDA margin from revenue, operating profit and depreciation.Inventory Turnover CalculatorTurns per year and days of inventory from COGS and average stock.Degree of Operating Leverage CalculatorHow many percent operating profit moves for each percent of sales, from contribution and fixed costs.Rule of 40 CalculatorAdd revenue growth to profit margin and measure the sum against the 40 line.Churn Rate CalculatorMonthly churn and the implied average customer lifetime, from starting and lost customers.Customer Retention Rate CalculatorMonthly retention and what it compounds to over twelve months.Customer Lifetime Value CalculatorWhat one customer contributes in total, from monthly revenue, gross margin and churn.LTV to CAC Ratio CalculatorLifetime value against acquisition cost, measured on the 3:1 rule of thumb, plus months to recover CAC.CAC Calculator (Customer Acquisition Cost)Blended and paid-only CAC from sales and marketing spend and the customers won.MRR Growth Rate CalculatorMonthly growth, net new MRR, ARR and the annualised rate from this month and last.Conversion Rate CalculatorConversion rate from visitors and orders, and the extra traffic it would take to match a target rate at today's rate.
Interest & Return41
Simple InterestFind the final amount when interest is paid on the principal only.Compound InterestFind the final amount when interest earns interest.Savings Plan MaturitySee what a fixed monthly deposit grows to by the end of the term.Loan Monthly PaymentCalculate the level monthly payment on a loan from amount, rate and term.Rule of 72Estimate in your head how long money takes to double at a given rate.ROI CalculatorGet return on investment and profit from what you put in and got back.Annualised ReturnConvert a short-period return into a yearly equivalent.Loss Recovery CalculatorHow big a gain you need to get back to even after a given drop.Real Interest RateStrip inflation out of a nominal rate to see the gain in purchasing power.Interest Income TaxTake the 15.4% tax off your interest to see what you actually receive.Monthly Amount to Reach a GoalHow much to set aside each month to hit a target by a date.Present ValueWhat money arriving years from now is worth today.Borrowing Limit from a Monthly PaymentTurn what you can pay each month into how much you can borrow.Interest Saved by OverpayingHow much interest disappears when you pay down principal early.Daily InterestInterest for a handful of days, worked out day by day.First Payment: Interest vs PrincipalSplit the first month’s payment into interest and principal.Instalment Fee to Effective APRConvert a flat instalment fee into the annual rate it really represents.Future Price with InflationWhat today’s price becomes after a number of years.Average Cost of Two BuysThe blended price when you bought in two lots.Return Needed to Break EvenHow far it must rise to cover the fees you already paid.Emergency Fund TargetHow many months of expenses to keep in reserve.Bond Current YieldTurn face value, coupon and purchase price into the yield you actually get.Effective Annual RateThe same headline rate pays differently depending on how often interest is added.Debt Payments Against IncomeSee what share of your take-home pay the monthly repayment eats.Remaining Loan BalanceHow much principal is still owed after a number of payments.Cost of an Interest-Only PeriodHow much extra interest a grace period adds over the life of a loan.Months to Pay It OffPayoff time and total interest from a balance, a rate and a fixed monthly payment.How Long Savings LastHow many years a lump sum lasts when you draw a fixed amount each month.Payback Period CalculatorHow many months an upfront investment takes to come back out of monthly net cash flow.Savings Rate CalculatorYour savings rate from take-home pay and the amount saved, plus how long a year of expenses takes.FIRE Number CalculatorThe portfolio that supports your yearly spending at a given withdrawal rate.Rent-to-Income Ratio CalculatorWhat share of gross monthly income your housing costs take, against a chosen guideline.NPV CalculatorNet present value and the profitability index for a level yearly cash flow.IRR Calculator (Approximate)Internal rate of return from an upfront cost and a level yearly return.WACC CalculatorWeighted average cost of capital from the weights, the two costs and the tax rate.DSO Calculator (Days Sales Outstanding)How many days it takes to collect, from revenue and the receivables balance.Debt Snowball vs Avalanche CalculatorWhich order clears two debts faster, and how much interest the choice costs.Credit Utilisation CalculatorUtilisation from balances and limits, plus the balance and paydown a target implies.Mortgage Overpayment CalculatorHow many months and how much interest an extra monthly payment removes.50/30/20 Budget CalculatorSplit take-home pay into 50% needs, 30% wants and 20% saving, and compare with what you actually spend.Pension Contribution Gap CalculatorThe monthly contribution that closes the gap between the pot your target retirement income needs and what you have.
Concentration19
Concentration CalculatorGet percent concentration from the mass of solute and solution.Water Needed to DiluteHow much water to add to bring a solution down to a target concentration.Mixing Two SolutionsFind the resulting concentration when two solutions of different strengths are combined.Make a Saline SolutionWork out the mix needed to make a given amount at a target concentration.Fold Dilution CalculatorConvert a dilution like "1:1000" into the millilitres of stock you need.% to ppm ConverterConvert a percentage concentration into ppm and mg/L.Dilute Spirits to a Target ABVHow much water to add to bring a drink down to the strength you want.Syrup to Water RatioSplit a batch into the parts a 1:4 style ratio calls for.Blend Two Strengths to a TargetHow much of each liquid to combine for the concentration you want.Reduce to Raise ConcentrationHow much water to boil off to reach a target strength.Stock Solution to Target ppmHow much of a percentage-strength stock makes a solution at a target ppm.Two-Part Mix (Resin : Hardener)Split a batch of epoxy or paint into its two components.ppm to PercentConvert a parts-per-million figure into a percentage and into mg/L.Solution Volume for a Target StrengthFind how much solution the solute you have must end up in to reach a given strength.Coffee to Water Ratio CalculatorHow much water to pour for a given dose and brew ratio.Serial Dilution CalculatorThe concentration left after diluting by the same factor several times.Pool Chlorine Dose CalculatorHow much chlorine product to add, from pool volume and the current and target free chlorine.Pool Salt CalculatorSalt and bags needed to bring a saltwater pool from its current reading up to target.Pool Drain and Refill CalculatorWhat share of the water to drain and replace to bring cyanuric acid, salt or hardness down to target.
Scores & Targets11
Score to PercentageConvert a mark out of any total onto a 100-point scale.Attendance CalculatorGet your attendance rate and how many more sessions you can miss.Achievement RateCompare actual results against a target and see what is left.Win Rate CalculatorGet win percentage and the win-loss gap from a record.Score Needed for a Target AverageWhat you must average on the remaining tests to reach your goal.Weighted Grade CalculatorYour final mark once midterm, final and coursework weights are applied.Points to the Pass MarkThe distance from where you are to the pass mark, in points and percent.Daily Pace to FinishHow much to get through each day to hit the goal in time.Raw Score from PercentageTurn a percentage back into the actual mark when you know the maximum.Sessions Still NeededCount how many more times you must show up to hit an attendance target.Grade Curve CalculatorYour adjusted score when the class average is shifted to a target.
Tax rates and interest conventions differ by country and product — check your contract for real transactions.