Business arithmetic
Interactive tools with transparent methods. Change the inputs, check the example and use the result with its assumptions.
Gross Margin Calculator
Gross margin is revenue minus included cost of goods, divided by revenue, multiplied by 100. Revenue of 1,000 and cost of 650 gives a gross profit of 350 and margin of 35%.
Markup Calculator
Markup equals selling price minus cost, divided by cost, multiplied by 100. Buying at 80 and selling at 100 gives a 25% markup, while the margin is 20%.
Target Margin Selling Price Calculator
Required selling price equals unit cost divided by one minus the target-margin fraction. A cost of 60 and a 40% target margin gives a price of 100.
Unit Price Calculator
Unit price equals total package price divided by quantity. A package costing 18 for 12 equivalent units costs 1.50 per unit.
Discount Price Calculator
Discount amount equals original price multiplied by the discount fraction. Subtract it from the original price to obtain the price after discount.
Stacked Discount Calculator
Apply each discount to the price remaining after the previous one. A 20% reduction followed by 10% reduces 200 to 144, equivalent to a total reduction of 28%.
Add a Tax Rate Calculator
Tax amount equals taxable subtotal multiplied by the entered rate divided by 100. A subtotal of 250 at an assumed 8% rate gives tax of 20 and a total of 270.
Tax-Inclusive Price Split Calculator
For a total that includes one percentage tax on its base, divide the total by one plus the rate fraction. An inclusive total of 108 at an assumed 8% separates into 100 base and 8 tax.
Billable Hourly Rate Calculator
Modeled hourly rate equals annual gross earnings target plus annual overhead, divided by billable weeks and billable hours per week. Separate billable work from total time worked.
Project Cost Estimate Calculator
Base estimate equals hours × hourly rate plus direct expenses. Add the selected percentage of that base as contingency to obtain the modeled project estimate.
Break-Even Sales Units Calculator
Break-even units equal fixed costs divided by selling price minus variable cost per unit, rounded up. The model requires a positive contribution per unit.
Inventory Days of Coverage Calculator
Days of coverage equal usable inventory divided by average daily demand. A stock of 420 units at 30 units per day covers 14 days in this simplified model.
ROAS vs ROI: revenue return is different from profit return
ROAS divides attributed revenue by ad spend. Here ROI divides revenue minus all included costs by those costs. Revenue of 1,200, ad spend of 200 and product costs of 600 gives 6× ROAS but 50% all-cost ROI.
Margin vs markup: one profit, two denominators
Margin divides profit by revenue; markup divides the same profit by cost. Buying for 80 and selling for 100 produces a 20% margin and a 25% markup.
Sequential discounts vs adding discount percentages
Sequential discounts multiply the remaining price fractions. A 20% discount followed by 10% off the reduced price gives a combined 28% discount, not 30%.
Break-even units vs break-even sales revenue
Break-even units divide fixed costs by contribution per unit. Break-even sales revenue divides fixed costs by the contribution-margin fraction. With fixed costs of 1,000, price 20 and variable cost 12, break-even is 125 units or 2,500 in sales.
Break-even ROAS table by contribution margin
In the simplified model, break-even ROAS equals one divided by the pre-ad contribution-margin fraction. At a 40% contribution margin, revenue must equal 2.5 times ad spend to cover that spend.
Extra sales needed to recover profit after a discount
Required volume multiplier = original margin fraction ÷ (original margin fraction − discount fraction). At a 40% pre-discount contribution margin, a 10% price discount requires 33.33% more units to preserve contribution.
Discount percentages and final prices from a base of 100
A discount subtracts a percentage of the original price. This base-100 table separates the amount saved from the remaining price, so you can scale both to your own amount.