# Phone numbers

How should a phone number (MSISDN) be formatted in E.164? Sinch provides utility tools that help with correct formatting.

The phone number should be specified according to the E.164 number formatting ([http://en.wikipedia.org/wiki/E.164](http://en.wikipedia.org/wiki/E.164)) recommendation and should be prefixed with a `+`. For example, to verify the US phone number 415 555 0101, the phone number should be specified as `+14155550101`. The `+` is the required prefix and the US country code `1` prepended to the local subscriber number.

The Android SDK provides API for formatting phone numbers. The primary class for this functionality is [PhoneNumberUtils](https://developer.android.com/reference/kotlin/android/telephony/PhoneNumberUtils). The function [formatNumberToE164](https://developer.android.com/reference/kotlin/android/telephony/PhoneNumberUtils#formatnumbertoe164) should be especially useful to convert the number user has typed to format accepted by the Sinch API.
A key thing when parsing user input as a phone number is the concept of *default country ISO*. If a user enters their number in a local format, the parsing must know which region / country to assume. Sinch SDK provides a simple helper method to get the default country ISO code.

Example usage:


```kotlin
// Get user's current country code by carrier info
val defaultCountryIso = SinchPhoneNumberUtils.getDefaultCountryIso()
```

Important!
When passing a number as a string to create a `Verification`, the string should contain a number in *E.164* format.

A number can be formatted as *E.164* like this:


```java
val phoneNumberInE164 = PhoneNumberUtils.formatNumberToE164(phoneNumberString, defaultRegion);
```