Definition of that's about the size of it in US English:

that's about the size of it

phrase

informal
  • Said to confirm someone's assessment of a situation, especially of one regarded as bad.

    • ‘He enjoys a beer, but that's about the size of it, just as he does a party, a cigarette in his hand and the company of available young women.’
    • ‘Yes, it is certainly more enjoyable to drive around in an open top car, but that's about the size of it.’
    • ‘He'll do one or two key interviews, and that's about the size of it.’