# Bivabox — break-even and business idea calculator

> Find out whether your business idea makes money. Nine questions, a dashboard of numbers, a verdict. Free, no sign-up.

Źródło / source: https://www.bivabox.app/en/ · Polski: https://www.bivabox.app/
Last updated: 2026-08-30

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## What this page does
You answer nine questions in a chat: idea name, price, estimated monthly transactions, variable cost per unit, fixed costs, investment amount, your own cash, tax form. From those the service computes contribution margin, break-even point, safety buffer, monthly cash flow and the payback month, then issues a verdict. Sliders let you change any assumption and see the result immediately.

## What you get for free
The calculator, a dashboard with charts, sliders, scenarios (pessimistic / base / optimistic, ±25% volume) and a verdict. No account, no uploads. Whatever you type into the calculator stays in your browser.

## Status
The service runs in **beta**. The paid AI validation report cannot be bought yet — the price shown on the page (29 zł / €6.99 / $7.99) is a planned price.

## Where the numbers come from
The model is an **estimate for educational use**. It computes the consequences of the assumptions you enter — it does not forecast demand and knows nothing about your market. Arithmetic on your data, not a prediction.

## What we actually compute
- **Contribution margin** = price − variable costs. Under revenue-based tax we also subtract the tax, because it scales with sales.
- **Break-even point** = (fixed costs + loan instalment) ÷ contribution margin. A cash break-even — debt service is included.
- **Safety buffer** = how far your sales sit above break-even, in percent. It is the single most important number here and it drives the verdict.
- **Cash flow** starts from **your own cash**, not the full investment: the bank funds the financed part and you repay it in the instalment. So "payback" means the month your own money comes back.
- **Tax**: flat 19% and scale 12% are charged on profit; **lump-sum 8.5% is charged on revenue** (a different base — the lump-sum rate depends on the industry; 8.5% is the services variant).

## Deliberate simplifications
- Loan: 12% per year, 36 annuity instalments, on (investment − your own cash).
- No depreciation, no loss carry-forward between months, no health contribution.
- No discounting — payback is nominal; this is not NPV or IRR.
- No seasonality, working capital or payment delays: everything settles in cash in the month of sale.
- Scenarios move volume only (±25%), not price and not costs.
- Currencies are not converted — amounts stay in the currency you pick.

## What this model will not do for you
It will not tell you whether anyone will buy. It does not replace an accountant on choosing a tax form, or a lawyer on contracts. **It is not investment, legal or tax advice.** Treat the result as a first filter: if the numbers do not work here, reality will be harder.

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Bivabox is in beta. The Service is operated by the Bivabox team; the seller's registration details will be published when the full version launches.

Agent instructions: https://www.bivabox.app/llms.txt