Getting started
What OtterCalc is and your first two minutes in it.
OtterCalc is a notepad for thinking through anything with numbers in it: a budget, a trip, a quote, a back-of-the-envelope idea. You write in plain words, one thought per line, and every line shows its answer on the right as you type. Nothing to set up, no formula bar, no cells to reference. Change a number anywhere and every line that depends on it updates at once. All the examples in these docs are live, computed by the real engine as the page loads.
A real two-minute example
Most documents look like this: a few named values, some math on them, and a question answered at the end. Give a value a name with =, then use that name below. Type this, change a number, and watch everything follow.
Sections and blocks
This is the one structural idea worth learning early. A blank line starts a new section, and so does any line of plain text or a # heading (see Basics). The words subtotal, average, and the chart words pie, bar, and line all act on the run of values directly above them, so each section can sum or chart just its own lines. Get this, and long documents organize themselves.
total reaches across the whole document
The one keyword that ignores sections is total: it adds every value in the document and never double-counts a subtotal. So you can subtotal each section and still get one grand total at the end. Charts follow the same block rule as subtotal: one word turns the values above into a picture. The Totals and Charts pages have the exact rules.
It understands more than arithmetic
Money converts with live exchange rates, dates count themselves, and units behave. Each of these has its own page in the sidebar.
Where to go next
Read Basics for the writing rules, then dip into whichever topic matches your problem: Percentages, Money, Units, Dates, or the Structure pages for totals and charts. If you would rather poke around, open the Templates gallery and pick a ready-made calculation, a budget, a trip, an invoice, then start changing numbers. New in the top bar always gives you a blank page, and Settings & languages covers the theme, number format, and working in Spanish.