A travel converter with one input
Every other converter asks what you are converting before it asks for the number. That question is the tap that costs you the moment in the shop. Convert Once never asks — the price on the tag is also a temperature, a distance and a weight, and all of them answer at the same time.
$9.99 once. No subscription, no ads, no account.
Change country — the number you typed stays put. That is the whole idea: 500 yen re-read as 500 pesos, without retyping.
The magnitude rule
One number answering every unit only works while the answers stay readable. Nobody types 1,500 and means degrees. So every tile is graded against the size of the number — not a guess about you, a statement about the physical world — and the ones that are not a real thing at that scale get out of the way.
Tipping
A 20% button in Tokyo teaches the wrong thing. Convert Once carries the actual custom for all 152 countries — including whether a service charge is already on the bill, and whether tipping would be an awkwardness rather than a kindness. Tour guides get their own entry, because a guide's custom is frequently the opposite of the restaurant's.
The rest of it
Like the weather app. One location fix per launch, on the device, to work out which country you are standing in. Never stored, never sent anywhere.
A rate table is compiled into the app, so it answers on first launch with no network at all. Every figure says whether it is live, cached, built-in, or one you set by hand.
A price typed before the phone went into your pocket is one you have walked away from. A stale figure over the keypad is worse than an empty one.
Here and home, side by side, with the day difference — because the question is never "what time is it there", it is "can I call them".
Siri, Spotlight and the Shortcuts app answer conversions, rates and tipping. Put it on the Action button and it is one press from anywhere.
The rate for wherever you are, how old it is, and what tipping means there — on the home screen and the lock screen.
Price
Once. Not a subscription.
Free to try for your first five days of actual use — days you open it and type something, not days on a calendar. A travel app installed while you are planning should not expire before you land.
iPhone and iPad · iOS 18 or later