Free tool
Pond size calculator
Surface area and volume decide which rules apply to your pond, and how much of any product you'd use. Measure instead of guessing: Penn State notes most owners overestimate their pond's area by eye. 1 acre = 43,560 square feet; 1 acre-foot = 325,851 gallons (Penn State).
Checked Oct 4, 2026 · Source: Pond Measurements: Area, Volume and Residence Time (updated May 19, 2025) This may be outdated
How we calculate
Rectangle: length × width. Trapezoid: the average of the two unequal sides × width. Round: shoreline length squared, divided by Penn State's constant (547,390). Square feet to acres and acre-feet to gallons: One acre is 43,560 square feet, and one acre-foot (an acre of water one foot deep) is 325,851 gallons. For a roughly round pond, the shoreline length in feet, squared and divided by 547,390, gives acres. A bowl-shaped pond's average depth is roughly 0.4 times its deepest point. PFBC's grass carp form asks for the exact surface area, not a range or an estimate. Source: Penn State Extension, Pond Measurements: Area, Volume and Residence Time.
Checked Oct 4, 2026 · Source: Pond Measurements: Area, Volume and Residence Time (updated May 19, 2025) This may be outdated
Questions
Why does PFBC want the exact area?
1 acre = 43,560 square feet; 1 acre-foot = 325,851 gallons (Penn State). PFBC's grass carp form uses the surface area to set how many fish you may stock, and asks for an exact figure, not a range. Checked Oct 4, 2026
Can I use an online map to measure?
Yes: Penn State notes map websites with satellite imagery let you trace the shoreline and read off the area. Checked Oct 4, 2026