Rates, margins, break-even math, taxes, invoices, and small-business planning guides with worked calculation examples.
Our Business category is built for entrepreneurs, freelancers, and small-business owners who need clear answers to daily financial questions. Articles cover profit margin and markup calculations, break-even analysis, ROI measurement, discount and pricing strategy, and business valuation methods. Each guide includes scenario tables showing how changes in costs, prices, or volume affect your bottom line. Every article links directly to the matching calculator so you can apply the concept immediately to your own business numbers.
Margin, markup, and break-even are three separate questions
The guides most often confused with each other are margin and markup, and the confusion costs real money. Markup is profit as a percentage of cost; margin is profit as a percentage of the selling price. A 50% markup on a $10 item produces a $15 price and a 33% margin. Quote the 50% as a margin instead and the price is underquoted by a third. Read the margin guide and the markup guide as answering related but distinct questions, not interchangeable ones.
Break-even is a volume question, not a pricing one: fixed costs divided by the profit each unit contributes after variable cost. The pricing guide sets the price; the break-even guide then tests whether the volume needed to cover overhead at that price is realistic for your market.
Articles
Where to start in business
If you only read one article here, start with How to Build a Complete Price Quote: Markup, Overhead & Sales Tax Together, Markup Formula: A Complete Guide for Business Owners & Students, and How to Calculate Discount Percentage: Formula, Examples & Fake Discounts. These cover the most common questions in this category and link to the calculator that matches.
39 articles are published in this category so far. Each one follows the same structure: the formula or method, a worked example, a comparison table where relevant, and a direct link to the live calculator.
Context
The costs guides assume you will supply yourself
Business guides walk through the formula using round example costs, but the real cost categories that get left out of a first-pass estimate are payment processing (typically 1.5–3% plus a fixed fee), platform commission, returns, and a tax reserve. A 30% margin can be close to nothing once those are subtracted, and they are easy to miss because they arrive as separate line items rather than inside the cost of goods.
Fixed and variable costs also get mixed up in practice: rent and subscriptions are fixed, materials and per-transaction fees scale with volume. Putting a variable cost in the fixed bucket flatters a break-even estimate at high volume and understates it at low volume. Check which bucket your own costs belong in before running the numbers.
Scenarios
The scenario worth running before you change a price
Model a price cut and work out the extra volume needed to hold total profit flat. At a 30% margin, a 10% price cut needs roughly a 50% volume increase to break even on profit, which is the usual argument against discounting to win a deal. Run the reverse too: a price increase, and how much volume you could afford to lose before it hurt.
For pricing and freelance-rate guides, run a cost shock through the model (a supplier price rise, a platform fee increase) and check whether your current price still clears the margin you actually need after that shock.
Comparison
Profit on paper is not cash in the account
A business can be profitable by the numbers and still run out of cash, which is why a margin guide and a cash-flow guide can point in different directions. Margin ignores the timing of payments; if customers pay in 60 days and suppliers are owed in 30, the model shows profit while the account is empty.
Valuation guides answer a third question again, and the multiple they describe is only as reliable as the earnings figure it is applied to. Before using a rule-of-thumb multiple, check whether the earnings are adjusted for owner salary and one-off costs, because an unadjusted figure will not survive scrutiny from a real buyer.
Limits
What these guides cannot settle for your business
None of these guides know your tax jurisdiction, your allowable deductions, or your VAT/GST registration status. Tax and deduction figures are rough planning estimates; the number that matters for a filing should come from an accountant who can see your actual books.
They also cannot price competitive position. A guide can show the margin a price produces; it cannot tell you whether the market will actually pay it. Use the guide to rule out prices that mathematically cannot work, then test the remaining range against real customers.
FAQ
Frequently asked questions
What do the business guides cover?
These guides explain profit margin and markup, break-even volume, ROI, discount and pricing strategy, and business valuation methods. Each one walks through the formula, a worked example, and links to the matching calculator so you can apply the method to your own numbers.
Which business guide should I read first?
Start with the article closest to your immediate question. Common starting points in this category include How to Get a Barcode for Your Product: GS1, Fees, Resellers, Amazon’s Rules and What the Numbers Mean, Barcode Types Explained: UPC, EAN, Code 128, Code 39, ITF-14, GS1-128, Data Matrix and QR: Which to Use Where, Are Electronic Signatures Legally Binding? ESIGN, UETA, eIDAS and What Still Needs Ink, Pay Stub Requirements by State: What a Wage Statement Must Show (2026), and How to Write a Receipt: What to Include, With Examples. If you are not sure, start with the broadest one and use its links to reach a more specific guide.
Are the business guides and calculators free to use?
Yes. Every guide, calculator, and template on Do The Calculation is free, with no account or signup required.
What should I have ready before reading one of these guides?
It helps to have your revenue, cost of goods, fixed and variable costs, and, for pricing guides, your current price and volume on hand, since the guide’s worked example uses illustrative numbers and the value is in matching its method to your own figures.
How accurate is the information in these guides?
The guides use published, standard methods, and each one states its assumptions so you can check the working rather than take the output on trust. Business guides are planning estimates. Tax treatment, allowable deductions, and valuation norms vary by jurisdiction and industry. Confirm with an accountant before filing or pricing a sale.
What is the most common way to misread one of these guides?
The most common mistake in this category is confusing margin (profit as a percent of price) with markup (profit as a percent of cost), which are different numbers on the same transaction. Reading the worked example carefully before applying it to your own numbers usually catches this.
Can I compare more than one scenario using these guides?
Yes. Run the matching calculator once for a baseline, change one input, and run it again. Useful angles to compare in this category include gross vs net margin, break-even volume, price elasticity, cash timing, and tax and fee drag.
How do the guides relate to the calculators?
The calculator gives you the answer; the guide explains how that answer was reached and what to do with it. Every guide links to its matching tool, and the tool links back to its guide.
Which articles are most popular in business?
Featured articles in this category include How to Build a Complete Price Quote: Markup, Overhead & Sales Tax Together, Markup Formula: A Complete Guide for Business Owners & Students, and How to Calculate Discount Percentage: Formula, Examples & Fake Discounts.
How often is this content updated?
Articles are revised when the underlying method, published guidance, or the matching calculator changes. Each article shows its published and last-updated date so you can judge how current it is.
Can I use these guides and calculators on mobile?
Yes. Every guide and calculator page is designed to work on mobile, tablet, and desktop screens.
What should I do with the result after reading a guide?
Turn it into a next action: price or evaluate a real decision with the fees, taxes, and cash-timing gaps that a headline margin number leaves out. That is the intended outcome of pairing a written guide with a live calculator instead of publishing either one alone.