Practice gives you a fixed number of untimed questions with immediate answer feedback. Timed Round asks you to complete as many conversions as possible before the round clock expires. Speed Challenge gives every question its own time limit.
Difficulty changes the weights being converted. Easy uses whole numbers from 15–1000 grams or 1–35 ounces. Medium uses one decimal place from 15.0–5000.0 grams or 0.5–180.0 ounces. Hard can use two decimal places from 15.00–10000.00 grams or 0.05–350.00 ounces.
Answer Precision controls how your answer is rounded. One international avoirdupois ounce equals exactly 28.349523125 grams. To convert grams to ounces, divide by 28.349523125; to convert ounces to grams, multiply by 28.349523125. The app uses exact rational arithmetic, then checks whether your numeric answer rounds to the required precision.
When Both Directions is selected, questions alternate unpredictably between grams-to-ounces and ounces-to-grams. Equivalent numeric formatting is accepted, so an answer such as 62.10 is treated the same as 62.1 when appropriate.
You can press Enter to submit, P to pause, or Esc to end the current round. Timers pause automatically when the page is hidden.