Think with your brain.
Work with your thumbs.
Notes, math, unit conversions, and time zones — all in one scratchpad. Type a line, get an answer. Nothing leaves your device.
Calculate as you type
Every line evaluates instantly — no equals button, no modes. Plus a full scientific set: sqrt, log, trig, factorial, pi, e.
Convert anything
Length, volume, weight, temperature, data, speed, area, CSS units. Exact ratios, clean decimals.
Skip the timezone math
“9am PST to UTC”, “time in Tokyo” — written the way you'd actually say it.
Many thumbs
Keep a scratchpad for everything. Rename, reorder, search, import and export.
Private & offline
No account, no tracking, no network. Everything stays on your device.
Share & export
Send a thumb as text, or back it all up as JSON, Markdown, or CSV.
See it in action.
Real screens. Type it how you'd say it — the answer lands on the same line.
One app. Many thumbs.
A separate scratchpad for each corner of your life. Reorder them, rename them, keep them forever.
“The calculator I always wanted on my phone — it reads like my notes, and every line just works.”