About CalcRoost

Last updated: September 8, 2026

Why CalcRoost exists

Most calculator sites hide the math. You get a number, but not the formula behind it, not the rates that were assumed, and not the date the rates were last checked. When a platform changes its fees or a tax bracket moves, those tools quietly go wrong.

CalcRoost takes the opposite approach: every tool shows its formula on the page, every rate is an editable input with its default explained, and every benchmark cites an official source — Amazon Seller Central, the IRS, HMRC, state revenue agencies.

What we build

Today CalcRoost offers dozens of calculators across five clusters: real estate investing (cap rate, cash-on-cash, NOI), e-commerce seller fees and profit (Amazon FBA, Etsy, eBay, TikTok Shop and more), freelancer & tax (1099, self-employment tax, VAT), contractors (roof pitch, deck, fence, concrete), and beauty professionals (service pricing, color mixing).

How the numbers stay honest

Three rules govern every tool on this site. First, formulas are industry-standard and printed on the page — you can check the math yourself. Second, rates that change over time are always editable inputs, so a tool never becomes silently wrong. Third, every page lists its sources and a last-updated date.

When platforms change fees (they do, constantly), we update defaults — but you never have to wait for us, because you can always type the current rate yourself.

Who it is for

Property investors comparing deals, e-commerce sellers pricing products, freelancers estimating taxes, contractors quoting jobs, and beauty professionals setting prices. Especially: people who want to understand the number, not just receive it.

Independence

We do not take money to rank, recommend, or feature anything. The site is funded by advertising only, and ads never influence tool logic or content.

Contact

Suggestions, corrections, or requests for a new calculator: hello@calcroost.com.