Find the Salesforce ID of a Record Type

Get Record Type ID for a Standard Object

In Salesforce Classic

1. Click Setup.
2. Under 'Build,' click Customize | click the object of your choice | Record Types.
3. Click on the Record Type Label name and inspect the URL to get the ID.

In Lightning Experience

1. Click the gear icon.
2. Click Setup.
3. Select the Object Manager.
4. Select the object of your choosing.
5. Select Record Types.
    
6. Select the Record Type Label name and inspect the URL to get the ID.

Get Record Type ID for a Custom Object
 

In Salesforce Classic

1. Click Setup. 
2. Under 'Build,' click Create | Objects | click on the object of your choice | the name of the record type.

In Lightning Experience

1. Click the gear icon.
2. Click Setup.
3. Select the Object Manager.
4. Select the object of your choosing.
5. Select Record Types.
6. Select the Record Type Label name and inspect the URL to get the ID.

Note:

In Classic, the URL for this page looks like this:

https://na1.salesforce.com/setup/ui/recordtypefields.jsp?id=012300000012BYN&type=

The 15 alphanumerical characters found between "jsp?id=" and "&type=" constitute the ID of the record type (For example, 012300000012BYN).

In Lightning Experience, the URL for this page looks like this:
 

https://na1.lightning.force.com/lightning/setup/ObjectManager/Case/RecordTypes/012300000012BYNQAG/view?0.source=alohaHeader
 

The 15 alphanumerical characters can be found by removing the last 3 digits of the characters between "RecordTypes/" and "/view' (For example, 012300000012BYN by removing the QAG in 012300000012BYNQAG).