Free
Calculators and tools
Percentages, rule of three, VAT, weighted average, travel allowances and a non-breaking space generator. They do the maths for you, no registration.
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Pricing strategy calculator
Selling price from costs and margin, margin from price, and the difference between margin and markup, the most common pricing mistake.
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Travel allowances
The allowance for a business trip by car: kilometres times the basic rate plus fuel consumed. The 2026 statutory rates are pre-filled, you…
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CLV calculator
Customer lifetime value: how much the average customer spends with you over the whole relationship, and how much of that is profit.
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CPA calculator
Cost per acquisition: how much one acquired customer or conversion from a campaign costs on average.
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VAT calculator
Both directions of the value-added tax calculation: add the tax to a net price, or work it back out of a gross price. Set the 21 % or 12 %…
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Which generation do I belong to
Enter your birth year and find out which generation you belong to, what its range is and how old you are this year. From the Silent…
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Nbsp generator
Adds non-breaking spaces to your text according to the rules of Czech typography: prepositions, abbreviations, units after numbers, dates…
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PNO calculator
Share of costs in revenue: what percentage of your sales the advertising swallowed. The basic metric of Czech PPC campaigns.
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Percentage calculator
The three most common percentage calculations: how much is X % of a number, what percentage one number is of another, and by what…
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ROAS calculator
Return on advertising spend: what percentage of revenue every crown invested in the campaign returned to you.
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ROI calculator
Return on investment: what percentage the money you put in earned, or lost. The result updates as you type.
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ROMI calculator
Return on marketing investment: by what percentage the return attributable to marketing exceeded its costs.
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SEO calculator
The value of organic traffic in crowns: what search engines bring you each month and how your SEO investment pays off.
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Rule of three
Direct and inverse proportion without setting up an equation: enter three known values and the calculator works out the fourth as you type.
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Weighted average
An average where every value has its own weight: grades of varying importance, an average price from purchases of different sizes. Add rows…
What the calculators are for
Every calculator runs right in your browser and the result updates as you type: no button, no waiting, no registration. Below each calculation you'll find the formula with the procedure and examples, so you know not just how much, but also why.
The maths calculators, that is percentages, the rule of three and the weighted average, handle the most common everyday calculations from discounts to grade averages. The business tools, that is VAT and travel allowances, work with current rates and statutory values. And the non-breaking space generator adds hard spaces to your text according to the rules of Czech typography, the same rules every text on this website goes through.