Free tools
Small things that do one job, with no account and no catch. Most of them also hand their result to Decka, if you want to run it in front of a room instead of on paper.
Reaction Time Test
Catch a falling ruler and read your reaction time where you caught it
Gerrymandering Simulator
Draw districts on one fixed town and compare the seats they produce
Payoff Matrix Calculator
Explore best responses and Nash equilibria in a 2×2 game
Repeated Prisoner’s Dilemma Simulator
Compare strategies, round by round, with a deliberate action flip
Portfolio Risk Calculator
See how allocation and correlation change two-asset portfolio risk
Paired Period Calculator
Compare raw timings, normalized periods and paired measurement spread
Tax Incidence Calculator
Move a per-unit tax between buyers and sellers on the same order book
Tier List Maker
Rank anything into tiers, and share the board
Icebreaker Questions
Questions with a concrete answer, sorted by room
Word Cloud Generator
Paste text and see what it is really about
Random Team Generator
Split a list of names into fair teams
Charades Generator
Random charades words by category and difficulty
Decision Wheel
Spin to pick a name, a task, or an answer
Drawing Prompt Generator
Random things to draw, by how hard they are to draw
Bingo Card Generator
Turn a word list into printable bingo cards
Exit Ticket Template
A three-minute check on the way out of the lesson
Team Charter Template
Eight questions a team answers once, together
Bring your room together
Use Decka to run live activities that your audience joins from their phones. No app or participant accounts.
Create a presentation