Judge a business decision by the numbers
Ten calculators for the decisions a business, a freelance practice or an investment actually turns on — what it costs to break even, whether a customer is worth acquiring, whether a return justifies the risk, and how self-employment tax really works. Everything runs in your browser.
The short answer
Most business-finance questions come down to a handful of standard calculations. Use a break-even calculator to find where price and volume cover your fixed costs; a customer lifetime value calculator to see whether acquisition pays back; an ROI or NPV/IRR calculator to judge a return, remembering that a bare ROI percentage ignores time while annualized ROI (CAGR) accounts for it; and a self-employment tax calculator, because 1099 income carries the full Social Security and Medicare tax that a W2 paycheck splits with an employer. Identical gross income does not mean identical take-home pay across the two.
Price it and know your break-even
unit economics for a small businessBefore anything else, a business needs to know what it costs to run and where the numbers actually turn a profit.
Judge a return before you commit
any investment, big or smallEquipment, a rental property or a trade — the question is the same. Does the expected return justify the risk and the capital tied up?
Freelance, contractor and VAT basics
self-employment isn't taxed like a paycheckIndependent income comes with tax mechanics and compliance a regular paycheck doesn't.
Break-even and what a customer is worth
Two numbers underpin almost every early decision a small business makes: the point at which it stops losing money, and whether the customers it buys are worth more than they cost to acquire.
Break-Even Point Calculator answers the first. Give it your fixed costs, your price per unit and your variable cost per unit, and it returns the units and revenue you need to cover the fixed base — plus the contribution margin (price minus variable cost) and the contribution-margin ratio, which is the fraction of every sale left over to pay for that base. The second question is Customer Lifetime Value Calculator, and it matters most when you're spending to acquire customers: it computes an LTV:CAC ratio and a payback period once you supply your acquisition cost.
A return has to beat time, not just zero
The most expensive mistake in judging a return is ignoring how long it took. A plain ROI percentage — net profit over what you put in — treats a 50% gain in one year and a 50% gain over five years as the same result. They are not remotely the same.
ROI Calculator reports net profit, ROI%, and the investment multiple, and the moment you add a holding period it also gives annualized ROI, or CAGR, which is the figure that actually lets you compare two investments held for different lengths of time. When the money doesn't arrive in one lump but as a stream — an initial outlay followed by periodic cash flows — NPV & IRR Calculator is the right tool: it discounts those flows to a net present value, solves for the internal rate of return, and reports a payback period and an accept/reject verdict.
- Investment A
- $10,000 in, $15,000 back after 1 year
- Investment B
- $10,000 in, $15,000 back after 5 years
- Plain ROI
- Both show 50% — indistinguishable
- Annualized (CAGR)
- A is ~50%/yr; B is ~8.4%/yr
The bare percentage hides the gap entirely. Add the holding period in ROI Calculator and the annualized figure separates them.
Property and trading have their own math
Some investments come with a standard vocabulary that a generic ROI number doesn't capture. A rental property is judged on net operating income, cap rate and cash-on-cash return — NOI is rent minus operating expenses before financing, cap rate expresses that against the purchase price, and cash-on-cash measures the return on the actual cash you put down rather than the whole price. It also reports monthly and annual cash flow and the gross rent multiplier, from the purchase price, financing terms, rent and operating expenses.
Trading has its own discipline, and Stock & Forex Position Size Calculator enforces the useful half of it: you size a position by risk, not by conviction. You choose what a losing trade may cost — a percentage of the account or a fixed amount — and the tool works backwards from your stop-loss to the number of shares, coins or forex lots that makes a stop-out equal exactly that. It also shows max loss, position value and risk:reward.
- 1Confusing cap rate with cash-on-cash return
Cap rate ignores financing; cash-on-cash is built on it. A leveraged purchase can show a modest cap rate and a strong cash-on-cash return, or the reverse — they answer different questions and both belong in the decision.
- 2Sizing a trade by conviction
Deciding how much to buy by how sure you feel is how one bad call erases ten good ones. Fix the loss you'll accept first, then let the stop distance set the position size.
Freelance income is taxed differently
A paycheck hides how much tax self-employment actually carries. Side Hustle Income Tax Calculator estimates US federal tax on 1099, gig or side income: self-employment tax (Social Security plus Medicare), the 50% deduction for half of that SE tax, your marginal income tax, an effective rate, and a suggested quarterly estimated payment — because independent income isn't withheld for you. It covers US federal tax specifically, not state tax or other countries.
When you're weighing a contract against a salary, 1099 vs W2 Income Comparison Calculator puts the two side by side at the same gross figure, across federal tax, self-employment tax, FICA, state tax, retirement, health insurance and business expenses.
Which one do I want?
Several tools here overlap. The short version:
| ROI Calculator vs NPV/IRR Calculator | A single lump-sum return — money in, money out, one period. | A stream of cash flows over time, discounted for the time value of money. |
|---|---|---|
| ROI Calculator vs Rental Property ROI Calculator | Any generic investment — net profit, ROI% and annualized return. | A property specifically — NOI, cap rate, cash-on-cash and cash flow. |
| CLV e-commerce model vs SaaS model | Reordering customers — average order value × purchases/year × lifespan. | Subscriptions — ARPU ÷ monthly churn, where lifetime is the inverse of churn. |
| Side-Hustle Tax Calculator vs 1099-vs-W2 Comparison | Estimating the tax and quarterly payment on income you already earn as 1099. | Deciding between a contract and a salaried role at the same gross. |
Why this set
Break-even, CLV, ROI, NPV/IRR, cap rate, SE tax — the calculations businesses actually run, each returning the intermediate figures (contribution margin, CAGR, cash-on-cash) rather than just one number.
Revenue, costs, salaries and income run client-side. Nothing you type is uploaded, which is the only reason it's reasonable to enter a real number.
The overlaps are the point — ROI against NPV, a contract against a salary, one CLV model against the other. The set is chosen so you can weigh options, not just get an answer.
Questions
What's the difference between ROI and annualized ROI (CAGR)?
Plain ROI is net profit over what you invested, and it ignores time entirely — a 50% return earned in one year and one earned over five years both read as 50%. Annualized ROI, or CAGR, spreads the gain across the holding period so you can compare investments held for different lengths of time. The ROI Calculator reports the annualized figure as soon as you add a holding period.
When should I use NPV/IRR instead of a simple ROI calculation?
Use ROI when a return is a single lump sum — you put money in and got money back. Use the NPV/IRR calculator when the return arrives as a series of cash flows over multiple periods, because it discounts those flows for the time value of money, solves for the internal rate of return, and gives a payback period and an accept/reject verdict that a single ROI percentage can't.
Does earning the same gross as a 1099 contractor and a W2 employee give the same take-home?
No. A W2 employee splits Social Security and Medicare with their employer and typically has benefits bundled in, while a 1099 contractor pays the full self-employment tax and covers those benefits themselves. At an identical gross figure the contractor keeps less. The 1099-vs-W2 comparison calculator lays the two out side by side so you can set a contract rate that actually closes the gap.
Does the VAT number validator confirm a VAT number is real?
No — it's a structural check only. It reads the two-letter country prefix and checks the national number against that country's expected format, so a pass means the number is correctly formatted. It does not contact the EU VIES registry, so it cannot confirm the number is actually registered or active. Use it to catch typos, not as proof of a valid trader.
How do I know if acquiring a customer is worth it?
Compare what a customer is worth over their lifetime against what they cost to acquire. The customer lifetime value calculator computes an LTV:CAC ratio and a payback period once you supply your acquisition cost — pick the e-commerce model for a business with reordering customers or the SaaS model for a subscription, and apply your gross margin so you're comparing net value rather than headline revenue.