About this tool
The Snow-to-Liquid Ratio Calculator converts between liquid-water equivalent and snow depth. The snow-to-liquid ratio (SLR) tells you how many inches of snow one inch of melted water produces: fluffy, cold, dry snow can exceed 20:1, while wet spring snow may be only 6:1 or 8:1. The long-standing rule of thumb is 10:1, meaning ten inches of snow melt down to one inch of water.
Choose a direction — liquid to snow (snow = liquid × ratio) or snow to liquid (liquid = snow ÷ ratio) — and enter the depth in inches, centimeters, or millimeters. You can type the ratio directly or let the tool estimate it from the surface air temperature using a Kuchera-style lookup: ≥28°F → 10, 20–27°F → 12, 10–19°F → 15, 0–9°F → 20, −20 to −1°F → 25, and below −20°F → 30, reflecting how colder air produces lighter, deeper snow.
Everything is computed in your browser. The result is shown in the same length unit you entered, alongside the ratio that was applied and the original input for reference. A ratio must be positive, and the depth cannot be negative; otherwise the input is rejected.
Frequently asked questions
What does a 10:1 ratio mean?
It means ten inches (or centimeters) of snow contain one inch of liquid water when melted. So 0.5 inch of liquid precipitation at 10:1 becomes 5 inches of snow. Ten to one is the classic default, but real ratios vary widely with temperature and crystal type.
How does temperature change the ratio?
Colder air generally yields lighter, drier snow with a higher ratio. This tool's optional temperature mode uses a Kuchera-style table: around 10:1 near 28°F, rising to 20:1 near 0°F and 30:1 below −20°F, so the same water makes much deeper snow when it is very cold.
Can I convert snow depth back to liquid?
Yes. Switch the direction to 'snow to liquid' and the tool divides the snow depth by the ratio to give the liquid-water equivalent — useful for estimating runoff, reservoir input, or how much water a snowpack holds.
Which units are supported?
Inches, centimeters, and millimeters. The ratio is dimensionless, so the output is returned in whatever length unit you selected for the input; just keep the input and output in the same system.
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