Bird Seed Quantity & Cost Calculator
Estimate how many pounds of seed, bags, and dollars your feeder setup uses per month based on capacity and refill rate.
Traffic spikes in late winter and during migration, so expect to refill more often those months. A squirrel baffle often pays for itself in seed savings within a season.
How it works
The calculator multiplies feeder capacity by how many feeders you run and how often you refill each one in a week, then scales that weekly figure up to a month using 4.345 weeks per month (the real average, since months aren't exactly four weeks). From the monthly pounds it works out how many bags you'll need, rounding up because you always buy a whole bag, and multiplies pounds by price per pound for a monthly cost.
Worked example: two 2 lb feeders, refilled about 1.5 times a week each. That works out to 2 lbs × 2 feeders × 1.5 refills × 4.345 weeks, which is 26.1 lbs a month. Buying that in 20 lb bags means 2 bags a month, and at $1.50 a pound that's $39.15 in seed. Add a suet cage or a nyjer sock and the same math applies separately for each specialty food, since those get emptied on their own schedule.
Refill frequency is the number most people guess wrong. Watch a feeder for a week before entering a number here rather than assuming it needs topping off daily; a well-placed tube feeder with two or three species visiting often only needs a refill every four or five days outside of winter.
FAQ
Why does the calculator use 4.345 weeks per month?
A year has 52.14 weeks spread across 12 months, so the average month is 4.345 weeks long, not an even 4. Using 4 would undercount seed use every month and leave you running out before the next bag purchase.
How do I know my price per pound if I only know the bag price?
Divide the bag price by the bag's weight in pounds. A $30 bag of 20 lb seed is $1.50 a pound, which is the number to enter here.
Why does seed use jump so much in winter?
Natural food sources disappear and birds need more calories to stay warm, so backyard feeders become a bigger share of their diet. Expect refill frequency to climb well above your summer baseline from late fall through late winter.
Is a squirrel baffle really worth the cost?
A determined squirrel can empty a feeder in an afternoon, which shows up directly in this calculator as extra refills per week. A baffle that stops that traffic often pays for itself in saved seed within one season.
Does buying seed in bulk actually save money?
Usually yes. Larger bags typically run a lower price per pound than small bags, and seed stored properly in a sealed metal or heavy plastic container keeps for months without losing quality, so buying a bigger bag less often is often the cheaper path once you know your real monthly usage.
For more on cutting seed waste, see how to choose the right bird feeder, how to store bird seed and keep pests out, and is backyard birding expensive: the real costs.