How Much Bird Seed Per Feeder
If you're wondering "how much bird seed per feeder should I buy?", this free calculator gives you a practical answer in pounds per day, per week, and per month — plus how long a bag of seed will last at your usage. Enter how many feeders you run, pick the bird traffic level that matches your yard, and set your bag size; everything updates instantly as you type.
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How to use this calculator
Enter the number of feeders you keep filled, choose the bird traffic level that best matches your yard — light, moderate, or heavy — and enter the bag size you normally buy. You'll see daily, weekly, and monthly seed amounts in pounds, an approximate cup measure, and how many days and weeks one bag lasts. Results update instantly as you change anything.
Try different scenarios: compare moderate versus heavy traffic to see what a busy winter would cost you, or change the bag size from 20 lb to 40 lb to see how much longer a bulk bag lasts. The traffic levels are rough estimates, so treat the answers as planning numbers, not exact science.
How it works
The math is simple multiplication on a daily seed estimate. Each bird traffic level is a rough estimate of what one feeder's visitors eat in a day:
- Light traffic: 0.25 lb (≈ 4 oz) per feeder per day
- Moderate traffic: 0.5 lb per feeder per day
- Heavy traffic: 1 lb per feeder per day
Daily seed = feeders × per-feeder amount, then weekly = daily × 7 and monthly = daily × 30. A bag's lifespan is bag size ÷ daily seed (days), divided by 7 for weeks. For example: 2 feeders at moderate traffic → 2 × 0.5 = 1 lb per day → 7 lb per week; a 20 lb bag lasts 20 ÷ 7 ≈ 2.9 weeks.
Real-world amounts swing with the seasons. Birds eat the most in late fall through early spring, when cold weather raises their energy needs and natural food is scarce — feeder traffic can easily double or triple summer levels, so plan winter buying at the heavy level. Nesting season also spikes demand as parents feed chicks. Species matter too: big eaters like grackles and jays empty feeders far faster than chickadees and finches, and spilled or squirrel-stolen seed can add 10–20% to what you put out.
Frequently asked questions
How much bird seed does one feeder use per day?
It depends on how busy your feeders are. This calculator uses three rough estimates: light traffic — about 0.25 lb (4 oz) per feeder per day; moderate traffic — about 0.5 lb per feeder per day; heavy traffic — about 1 lb per feeder per day. They are rough estimates, not precise measurements: actual use varies with season, species mix, and feeder design. Multiply the per-feeder amount by your number of feeders for the daily total.
How long will a 20 lb bag of bird seed last?
Divide the bag weight by your daily use. For example, two feeders at moderate traffic use about 0.5 lb each per day, or 1 lb per day total — so a 20 lb bag lasts about 20 days, or roughly 2.9 weeks. Very busy feeders can empty the same bag in 10 days or less, while quiet feeders can stretch it past two months.
How often should I refill my bird feeders?
Check feeders every two to three days and refill before they sit empty — seed that sits in damp feeders molds quickly and can make birds sick. In warm, humid weather, empty and scrub feeders about once a week; in winter, when birds eat the most, busy feeders may need refilling every day or two. The weekly and monthly totals above help you plan how often you'll be buying bags.
Do birds eat more seed in winter?
Yes. Birds burn far more energy staying warm, and in late winter and early spring there is almost no natural food available, so feeder traffic peaks — often two to three times summer levels. Nesting season (spring) also raises demand because parent birds feed chicks. A good rule is to plan for the heavy-traffic estimate from late fall through early spring, and the light or moderate estimate in summer.
What kind of bird seed should I buy?
Black-oil sunflower seed is the best single choice for most backyards — most seed-eating birds take it, and it has a thin shell. Cheap mixed bags heavy on milo, wheat, or red millet look like a bargain but most songbirds toss those fillers on the ground uneaten, where they sprout or mold. Whatever you buy, store it in a sealed, rodent-proof container in a cool, dry spot so it stays fresh.