We know full sovereign coin is 8 grams and half is 4 grams. But sometimes you cant tell it is full or half coin when it fixed to a ring or a holder. Here are some details that help us to tell.

1. Dot to Dot:

Full Coin: 20mm

Half Coin: 18mm

2. Cloud:

Full Coin: 13mm

Half Coin: 11.2mm

3. Head to Cloud:

Full Coin: 16.4mm

Half Coin: 14mm

4. Thick:

Full Coin: 1.5mm

Half Coin: 1.0mm