Bird Feeder Seed Calculator
Plan bird seed by week and month plus feeder refill days.
What it does
A busy feeder empties faster than memory suggests. Ten daily visitors at half an ounce each eat 5 oz a day, which is over 2 lb a week and near 9 lb a month.
The tool above turns daily visits into weekly, monthly, and refill timing. The default 10 birds with a 2 lb feeder need 2.2 lb per week and 9.4 lb per month, with 6.4 days per fill. Metric keepers get 980 g per week and 4.2 kg per month.
Per bird rate is the estimate. Small finches and chickadees land near half an ounce, while doves and jays eat more and scatter more. The first full feeder calibrates the yard better than any book number.
Feeder size sets chores. A 2 lb tube suits 10 birds for most of a week, while 20 birds cut that to about 3 days. Large hoppers stretch intervals but need more cleaning watch.
Clean beats full in wet weather. Clumped seed molds fast, so dump, scrub, rinse, and dry before refilling, and rake hulls under the feeder.
How to use
- Pick imperial (lb) or metric (g).
- Enter daily bird visits.
- Enter feeder capacity: 2 lb or 900 g suits many tube feeders.
- Read weekly seed first.
- Read monthly seed next.
- Read refill days and set a weekend refill.
Formula
- birds
- Bird visits per day.
- rate
- Seed eaten per bird per day.
- feeder
- Feeder capacity.
Metric uses 14 g per bird per day, with weekly grams and monthly kilos. Feeder grams divided by daily grams gives the same refill days as ounces.
Worked example
Example: 10 birds, 2 lb feeder
Imperial defaults: 10 birds per day with a 2 lb feeder. These are also the default values, so the page opens on this answer.
- Birds: 10 per day.
- Daily: 10 x 0.5 oz = 5 oz.
- Weekly: 5 x 7 = 35 oz, or 35 / 16 = 2.2 lb.
- Monthly: 5 x 30 = 150 oz, or 150 / 16 = 9.4 lb.
- Feeder: 2 lb holds 32 oz, so 32 / 5 = 6.4 days per fill.
- Tool shows 2.2 lb per week, 9.4 lb per month, 6.4 days per fill.
Reference table
| Birds | Daily | Weekly |
|---|---|---|
| 5 | 2.5 oz | 1.1 lb |
| 10 | 5 oz | 2.2 lb |
| 20 | 10 oz | 4.4 lb |
| 10 metric | 140 g | 980 g |
Limits
- Estimate only. Species mix shifts intake.
- Ignores spillage, which can reach a fifth of seed.
- Wet seed needs cleaning before the math matters.
- Sick bird events need feeders down, not refills.
Common mistakes
- Buying one small bag for a busy month.
- Letting wet seed cake in the tube.
- Hanging feeders with no cover from hawks.
- Raking never, then growing mold under hulls.
- Mixing old and fresh seed in one fill.
Try it yourself
Quick checks. Answers sit tucked under each question.
20 birds, 2 lb feeder?
Daily is 20 x 0.5 = 10 oz. Weekly is 10 x 7 / 16 = 4.4 lb. A 2 lb feeder lasts 32 / 10 = 3.2 days.
10 birds metric: weekly and monthly?
Daily is 10 x 14 = 140 g. Weekly is 140 x 7 = 980 g. Monthly is 140 x 30 / 1000 = 4.2 kg.
Questions
How much seed per week?
Multiply birds by 0.5 oz, then by 7 or 30. Ten birds eat 5 oz a day, or 2.2 lb a week and 9.4 lb a month.
How often to refill?
Divide feeder ounces by daily ounces. A 32 oz feeder at 5 oz a day lasts 6.4 days.
How much does one bird eat?
Near 0.5 oz per small bird per day. Jays and doves eat more, goldfinches less, so watch the first week and adjust.
Should I clean feeders?
Yes in wet spells. Dump clumps, scrub with dilute bleach, rinse, and dry fully before refilling.
Feeders or plants?
Plant natives and add water near cover. Feeders help in winter, habitat feeds all year.
Does this diagnose disease?
No. Seed math only. Sick birds need feeders down and local guidance.