This tool estimates post boil wort volume and gravity.

Notes:

• Tool is available only for registered users.
• Choose gravity unit.
• Enter starting wort volume (in any volume unit - i.e. liters, gallons, barrels, ...) and starting gravity.
• Enter boil time in minutes, hourly evaporation rate^* (10% is good starting value) and cooling shrinkage rate (in doubt enter 4%).
• Tool estimates post boil gravity (in chosen gravity units), evaporation per hour, total boiled off volume, cooling shrinkage volume and final post boil volume including trubs (in volume units used for starting volume).

^*Note: How to determine Hourly evaporation rate? Measure hot wort volume just before boil starts (for example 30 liters). After one hour of boil time measure wort volume again (for example 24 liters) which gives us 6 liters of hourly boil-off.
Hourly evaporation rate = Hourly boil-off / Starting volume = 6 / 30 = 0.2 = 20%