Percentage & Rate Calculators
A hundred one-formula calculators — discounts, tax, interest, concentration
📐 Results update as you type, and every page shows the formula.
Price & Discount20
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.
Tax & Payout16
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.
Percentage & Change22
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.
Interest & Return22
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.
Concentration12
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.
Scores & Targets8
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.
Tax rates and interest conventions differ by country and product — check your contract for real transactions.