🐦 Bird Feeder Refill Interval Calculator
Enter your feeder's seed capacity and your best estimate of daily consumption (from observation) to see roughly how often you'll need to refill it.
Capacity divided by daily use
One division gives the days a full feeder lasts, shown to one decimal place:
days = capacity (oz) ÷ daily consumption (oz/day)
80 ÷ 4 = 20.0 days 80 ÷ 8 = 10.0 days in a cold snapEighty ounces is a 5 lb feeder, since 16 oz make a pound. A 2 lb tube emptying at 6 oz a day runs 5.3 days. Multiply the daily figure by 365 for the year's buying: 4 oz a day is 1,460 oz, near enough 91 lb, or about four and a half 20 lb sacks.
Getting the daily figure, and what to do with it
- Measure, do not guess. Weigh what you pour in, note the date, and weigh what is left at the next top-up. Seed used over nine days, divided by nine, is your real rate.
- Redo it each season. The tool's own note says consumption rises in winter and around migration, and how much it rises depends on your region, the weather and which birds happen to be about that year.
- Feed the answer into your seed budget. Ounces per day times price per ounce is the running cost.
Frequently asked questions
How often should I refill a bird feeder?
Whenever it empties, and in practice at least every week or two so the seed stays fresh. An 80 oz feeder going at 4 oz a day empties in 20 days, which is longer than most seed should sit out.
How much seed do birds eat per day?
It depends entirely on how many birds find your feeder, the season and the weather, so there is no useful universal number. Measure your own consumption over a week or two and use that.
How long will a 20 lb bag of seed last?
320 oz at 4 oz a day is 80 days; at 8 oz a day it is 40. Enter the bag weight in ounces as the capacity to read the answer straight off this page.