Ice Machine Sizing Calculator

Ice machines are rated at conditions almost no real kitchen or shop floor meets. Sizing on the published 24-hour figure is why so many run short by mid-morning.

An estimate for shortlisting. Confirm output with the manufacturer at your actual ambient and incoming water temperature.

Nameplate output is a laboratory figure

Published 24-hour production is normally quoted around 21 °C ambient with 10 °C incoming water. A fish counter in a shop at 30 °C with 20 °C mains water gets substantially less — commonly 25–35% less. That gap, not the arithmetic of daily consumption, is what leaves counters short.

Peak, not average

A fish counter is rebuilt with ice before opening and topped up through the day; a bar draws most of its ice in the evening. What matters is whether the machine plus bin can meet the peak draw, not whether daily totals balance.

The bin is usually cheaper than the machine

Sizing for live peak production means buying a much larger machine that idles most of the day. A storage bin lets a smaller machine produce steadily and buffer the peak — almost always the cheaper and more reliable arrangement.

Link to or cite this tool

If this calculator is useful in a specification, tender document or forum answer, please link to it rather than copying the figures — the assumptions behind it are stated above and may be updated.

https://www.hvacrnexus.com/tools/ice-machine-sizing-calculator/

Working out the fan side

Once the refrigeration duty is fixed, the evaporator fans and any condenser fans are a separate calculation. Longwell publishes a set of fan-side tools — airflow, static pressure, fan laws and motor sizing — at longwellfans.com.

Equipment this calculation points to

Questions about this calculation

Why does my ice machine produce less than its rating?
Because the rating is quoted at favourable conditions — typically 21 °C ambient and 10 °C incoming water. Real installations are hotter and their water is warmer, and output falls roughly 1.5% per degree of ambient and 1% per degree of water temperature.
Do I need a storage bin?
Almost always. Without one the machine must produce at peak rate in real time, which requires a far larger and more expensive unit that then idles for most of the day. A bin lets a smaller machine run steadily and cover the peak from storage.
How much ice does a fish counter need?
Size it on the morning build plus top-ups rather than on total consumption — the counter has to be full before trading starts, and a machine with adequate daily output can still fail that deadline.

Send us the duty and we will quote matched equipment

Give us the figure this calculator produced, your room temperature and your location — we will come back with condensing unit and evaporator options, price and lead time, usually within one working day.