Twin Convert

Twin Convert is a two-sided converter. Change one value and the other updates immediately. Convert currency, length, mass, volume, and temperature. On a large iPhone display the two fields sit side by side. On a smaller display they stack on one screen, with a swap control between them. On iPhone Duo the fields sit on either side of the fold when the phone is open, and stack when it is closed. Currency uses a cached rate table and can refresh from the network. Conversion itself is free. Unlock once for unlimited favorite pairs and a 90-day currency chart (free includes 4 favorites and a 30-day chart). No account. No ads. Events stay on the device.