Backyard Ice Rink Calculator: Water, Fill Time, Liner, Boards and Freeze Time
Plan a backyard skating rink: gallons or litres of water for the ice thickness and the yard's slope, hose fill time, liner size, board count and low-end board height, the weight of the water, days to freeze at your temperature and the water for each resurfacing flood.
How it works
average depth = high-end thickness + slope ÷ 2 · gallons = length × width (ft) × average depth (in) ÷ 12 × 7.48 · fill time = gallons ÷ hose gal/min · boards = perimeter ÷ board length (rounded up) · low-end board height ≥ thickness + slope + 4 in · liner = rink + the larger of 5 ft or (2 × board height + 12 in) · ice a day ≈ (32 °F − average °F) ÷ 15 in
A backyard rink is a shallow pond held in by boards and a liner. Water finds its own level, so the slope of the yard decides most of the numbers: the high corner gets your target ice thickness and the low corner gets that plus the whole drop. The average depth, and so the water bill, is the target thickness plus half the slope, and the low-end boards must stand taller than the deepest water with a few inches of freeboard. The liner has to run up the boards and fold over the top, so it is cut at least 5 ft longer and wider than the rink, more for tall boards. Fill it in one continuous pour so the water freezes as one slab. The water weighs about 8.34 lb a gallon (1 kg a litre) and the ice weighs the same, so a big rink holds many tons. Ice growth is a matter of cold: a common rink-builder rule is about 1 in of ice a day for every 15 °F (8.3 °C) the 24-hour average sits below freezing, so −10 °C (14 °F) gives a little over an inch a day. Growth slows as the ice thickens, and snow on new ice stops it altogether. Change the inputs to see how the slope and the target thickness drive water and board height.
Worked example
A 40 × 20 ft rink with 4 in of ice at the high end and a 6 in slope averages 4 + 6 ÷ 2 = 7 in of water and 10 in at the low end. Volume = 40 × 20 × 7 ÷ 12 = 466.7 cu ft × 7.48 = 3,491 gallons, a 7.3-hour fill at 8 gal/min, and the water weighs about 29,114 lb. The 120 ft perimeter needs 15 eight-foot boards, at least 14 in tall at the low end, a 45 × 25 ft liner and 34 brackets. At an average of −10 °C (14 °F) the ice grows about 1.2 in a day, so it takes about 4 days to skate and 9 days for the low end to freeze solid.
Sources: Inch Calculator: Ice rink volume and fill time calculator · Sniper's Edge Hockey: Backyard rink tricks, tips and lessons learned
Frequently asked questions
How much water does a backyard rink need?
Multiply length × width in feet by the average depth in inches, divide by 12 for cubic feet and multiply by 7.48 for gallons. A level 20 × 40 ft rink with 4 in of water needs about 1,995 gallons; every inch of slope adds half an inch to the average depth.
How do I measure the slope?
Drive stakes at the corners, run a string level (or a laser) from the highest corner and measure the gap between the string and the ground at each stake. The biggest gap is the drop. Do it before buying boards, because it sets their height.
How thick should backyard rink ice be?
At least 3 in of solid ice for kids and light skating, and about 4 in for adults and hockey. Most builders flood 3–4 in at the high end and let the low end be deeper.
How big should the liner be?
At least 5 ft longer and wider than the rink so it runs up the boards and folds over the top, more for tall boards: add twice the board height plus about a foot of slack. Use a white or clear liner of 5–6 mil or thicker.
How cold does it need to be to freeze a rink?
The 24-hour average needs to stay below freezing, ideally around −7 °C (20 °F) or colder. At about 17 °F a still rink gains roughly an inch of ice a day; near 30 °F it barely freezes and sunny days can melt it back.
Will the rink kill my grass?
Usually not if it comes down promptly in spring. A white liner and an early teardown once the thaw starts limit the damage; leaving a soggy liner on the lawn for weeks does the harm.
Related calculators
Rules of thumb from backyard-rink building practice. Ice growth depends on wind, sun, snow cover and water depth, so check the ice thickness in several places before anyone skates.