Capacity calculation in Tezos is tricky and most of the currently available tooling online gives very inaccurate capacity numbers, confusing both validators and delegators alike. This is an attempt to show how capacity for each validator can be calculated and forecasted, allowing validators to plan their reserves, and delegators to understand whether their validator can accept additional delegations. Using this capacity planner tool, a validator can never run out of available capacity.
In order to successfully create a block (bake) or assist in creating a block (endorse), a Tezos validator must deposit a certain amount of XTZ tokens. If there are enough capacities, the validator can successfully bake or endorse these blocks. If there are not enough capacities, the validator will be unable to bake or endorse and miss out on available rewards for itself and its delegators.
For Tezos, the number of baking and endorsement scheduled for a validator is determined ahead of time for several cycles by the protocol. For each row in the table that shows "Exact", the amount of deposit required is an exact calculation of how much this validator needs to put up to fulfill all its deposit obligations. For each row that shows "Estimate", the planner forecasts using the number of rolls and overall network stats.
First find your validator, then review whether you have enough XTZ in your baking account to fulfill all future obligations. The last column of the table, "Additional Self-Bond Required", should show zero for all cycles. Using this tool, a validator can never run out of available capacity by depositing the necessary self-bond at the right cycles.
First find your validator, then use the slider to input the number of extra XTZ tokens you would like to delegate to this validator. Make sure the last column of the table, "Additional Self-Bond Required", show zero (0) for all cycles. Zero means the validator has enough capacity for your additional delegation. If this column has non-zero numbers, the validator must deposit additional token to its own account, otherwise, it will fail to earn all of the potential rewards.
This tool does not take in account the deposits required for "stolen" blocks (bake or endorse). This tool also does not take in account the rewards earned, so the final numbers are conservative.