Special relativity: Lorentz factor, time dilation, length contraction, total and kinetic energy and momentum at a given speed.

Snell's law: refracted angle between two media (names or indices), critical angle and total internal reflection check.

Wave speed, frequency and wavelength, plus the Doppler-shifted frequency for sound (moving source or observer) or light.

Basketball efficiency from box-score numbers: eFG%, true shooting %, points, per-36 rates and assist-to-turnover ratio.

Convert American, decimal, fractional odds and probability; add the other side for margin, or your own chance for Kelly.

Work (force x distance x cos angle), kinetic and potential energy, and power, with joule, kWh, calorie and horsepower units.

Baseball rate stats from counting stats: AVG, OBP, SLG, OPS, ISO, BABIP for batters; ERA, WHIP, K/9, BB/9, FIP for pitchers.

Cricket batting average and strike rate, or bowling economy, average and strike rate, from raw career or match numbers.

Darts checkout routes for a remaining score of 2 to 170: the fewest darts that finish on a double, with alternatives.

Elo rating update after a game: win probability for each side, new ratings and the points exchanged.

Cycling FTP from a 20 or 8 minute test, watts per kilogram, and the seven Coggan training zones in watts.

Synonyms and antonyms of a word, ranked by relevance, with parts of speech.

Find words matching a crossword or Wordle pattern: t??k finds task, trek; ? is one letter, * any letters.

Wordle-style feedback for a guess against an answer: green, yellow and grey squares with correct duplicate-letter handling.

Historical events, births, deaths or holidays on a calendar date (month and day), with years and linked article titles.

Compare Wikipedia attention across 2 to 5 topics: total and daily average views, share of the group and growth over the window.

Word completions for a prefix, ranked by how common they are, for typeahead and name ideas.

Perfect and near rhymes for a word, with syllable counts, ranked by how common they are.

Words spelled similarly to the input: spelling suggestions. Common misspellings also appear in the vocabulary.

Check whether two words or phrases are anagrams, ignoring case, spaces, punctuation and accents; shows the letter differences.