The below guide is intended as exactly that, a guide! There is a lot to be said for lift capacities but the most crucial thing to remember is to correctly weight yourself in the water.
The lift capacity refers to the amount of weight a fully inflated BCD can keep afloat and is measured as a result of that weight (In Kilos or Pounds) - this is essentially the amount of negative weight the BCD can float.
Different types of diving may have different requirements in terms of the amount of lift you'll need, for recreational applications you'll likely be diving with a single cylinder a few accessories and not much else - So your lift requirements are relatively low!
Whereas if you were undertaking a tech dive with planned decompression and extended stops you may find yourself carrying one or more extra cylinders and further safety equipment, so in that case you would need a lot more lift.
- Tropical Diving - Thin wetsuits (<|3mm) an single cylinder; 8-12 kilos
- Recreational Diving - Thicker wetsuits (>3mm) / drysuits and single cylinder; 10-20 kilos
- Technical Diving - Variety of exposure suits and often multiple cylinders; 20-40+ Kilos