01Profitability
Price and margin determine contribution.
Net profit margin = Net profit ÷ Revenue
Start by seeing what remains after the costs included in your model.
Business decisions, reduced to useful numbers
Make business decisions with the numbers in front of you.
Free calculators for profitability, pricing, customer economics, growth, and cash planning—built to make your assumptions easier to see and compare.
- Free to use
- No sign-up
- 10 focused tools
Example business snapshot
Illustrative values
Revenue$120kMonthly example
Direct costs$48k40% of revenue
Gross margin60%$72k contribution
A
Acquisition$18k ÷ 90CAC · $200
B
Customer value$960CLV:CAC · 4.8×
C
Net burn$45k/moCash use
D
Runway8.0 mo$360k ÷ $45k
Each output is useful alone. The relationship between them gives the decision context.
Choose by business question
What are you trying to figure out?
Start with the decision, then choose the smallest useful calculation for it.
Profitability & pricing
Work from unit economics toward a viable price and profit.
01.01Profit Margin CalculatorSee how revenue and costs move gross, operating, and net margin.01.02Markup CalculatorCompare cost, selling price, markup, margin, and unit profit.01.03Break-even CalculatorFind the sales volume needed to cover fixed and variable costs.01.04Business ROI CalculatorTest an investment against projected return and payback time.01.05Pricing CalculatorBuild a unit price from costs, sales volume, and target margin.
Customers & growth
Check what customers cost, contribute, and retain.
Cash & survival
Understand monthly cash use and the time it leaves.
One connected operating picture
A metric changes the question after it.
Business numbers are not isolated scores. Read in sequence, they show where a decision starts—and what it affects next.
02Sales target
Contribution determines the break-even point.
Break-even units = Fixed costs ÷ Contribution per unit
A viable contribution per sale turns fixed costs into a concrete volume target.
03Growth quality
CAC and CLV show whether growth is sustainable.
CAC = Acquisition costs ÷ New customers
Compare what it costs to acquire a customer with the gross profit value the relationship may create.
04Operating time
Burn rate determines how long the business can keep operating.
Runway = Cash balance ÷ Net burn
When net burn is positive, available cash turns the current spending pattern into a time horizon.
A practical working loop
From an open question to a clearer range.
BizArith does not make the decision for you. It makes the assumptions and arithmetic easier to inspect.
- 01
Choose a question.
Begin with the uncertainty that could change your next move.
- 02
Enter your assumptions.
Use one period and one currency consistently across the inputs.
- 03
Review the result and its breakdown.
Read the main output together with the values behind it.
- 04
Compare scenarios before deciding.
Change an assumption, recalculate, and note what moves.
Before you calculate
Straight answers, before the inputs.
What the tools do, what they do not do, and how to use their results.
01What is BizArith?
BizArith is a focused collection of business calculators for testing questions about profitability, pricing, customer economics, growth, and cash planning.
02Are the calculators free?
Yes. Every BizArith calculator is free to use.
03Do I need an account?
No. You can open a calculator and use it without signing up or creating an account.
04Which calculator should I start with?
Start with the question you need to answer. Profit Margin is a useful first check for overall profitability, Break-even for a sales target, and Runway for cash planning.
05Does changing the currency convert values?
No. Currency changes the symbol and display formatting only. It does not convert amounts, so enter all monetary values in one consistent currency.
06Are the results financial or accounting advice?
No. Results are planning estimates based on the assumptions you enter. They are not financial, accounting, tax, investment, or legal advice.
07Can I use the calculators for scenario planning?
Yes. Change one or more assumptions, recalculate, and compare the outputs to see how a different price, cost, customer, or cash scenario affects the result.
Your next useful number
Start with the question costing your business the most.
Pick the closest business question, enter what you know, and turn uncertainty into a result you can compare.
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