Birdseed per Feeder Calculator
Work out how much birdseed your feeders use, how long a fill and a bag last, and how often you will refill, from feeder capacity and daily consumption.
How it works
Days per fill = feeder capacity ÷ daily use · Bag days = (bag lb × 2.2 cups/lb) ÷ (daily use × feeders)
Feeder demand swings with the season, the weather and which birds show up, so the daily figure is an average you refine by watching how fast your own feeders empty. Roughly one pound of mixed birdseed fills about 2.2 cups, which lets you turn a bag weight into cups and days. Do not fill a feeder far beyond a few days’ use: seed sitting in humidity clumps, grows mould and attracts pests, and uneaten seed is wasted money — so match the fill to how quickly the birds actually clear it.
Worked example
A single 4-cup feeder eaten at 2 cups a day empties in 4 ÷ 2 = 2 days. A 20 lb bag holds about 20 × 2.2 = 44 cups, so at 2 cups a day it lasts roughly 22 days, or a little over 3 weeks.
Frequently asked questions
How many cups are in a pound of birdseed?
About 2.2 cups per pound for a typical mixed seed, though it varies with the blend — light, fluffy mixes measure more cups per pound than dense sunflower-heavy blends. Weigh a cup of your own mix if you want a precise figure.
How full should I fill the feeder?
Only offer a few days’ worth at a time, especially in warm or wet weather. Seed left standing absorbs moisture, clumps and can grow mould that is harmful to birds, so a smaller, faster-turned fill is healthier than a brimming feeder that sits for weeks.
Why does consumption change so much?
Cold snaps, breeding season and migration all spike demand, while abundant natural food in late summer can empty your feeders slowly. Track your own refills over a few weeks to get an average that fits your yard.
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This calculator is for educational purposes. Double-check important results before acting on them.