This chicken feed bag calculator is for small-flock keepers who want a practical estimate from their own records. Weigh feed over a known period, enter the bag size and price, and add an estimate of usable feed already on hand. The calculations run in your browser; the calculator does not save or transmit your entries.
Calculate feed use and bag cost
Use kilograms for feed weight and pounds sterling for price. Enter a positive measured quantity and period. Existing stock is optional; if left blank, the calculator assumes you have no usable feed left for the purchase estimate.
Your measured use and bag details
Use a consistent measurement and count all top-ups during the period. The amount disappearing from storage can include spills or pest access, not just feed eaten by birds.
Your estimate
- Average measured use per day
- Estimated days one full bag lasts
- Estimated use over 30 days
- Estimated cost of that 30-day amount, by weight
- Whole bags to buy for the next 30 days, after current stock
- Estimated checkout cost for those whole bags
Thirty days is a simple planning period, not a calendar-month forecast. The whole-bag estimate assumes you can use the stock amount you entered.
How to measure chicken feed use
Choose a period that reflects your normal routine. Weigh or record the amount taken from the bag at the start, then include every top-up until the end of the period. Keep the units consistent and do not count feed that was put back into storage. A longer observation period can smooth out one unusually busy or quiet week, but it cannot remove changes caused by weather, age, laying, wastage or flock management.
If you are unsure how much remains in an open bag, estimate conservatively or weigh it. The calculator treats blank existing stock as zero so that it does not accidentally subtract an unknown quantity from the purchase estimate.
What the feed calculator does and does not tell you
The bag-duration estimate assumes that the measured average daily use continues unchanged. The 30-day amount is average daily use multiplied by 30. Its cost is the proportional share of a bag price. The checkout estimate rounds the amount needed after entered stock up to whole bags.
Do not use this estimate to decide how much to feed
It does not assess a bird's nutritional needs, feed quality, age, health, access or whether every bird can eat. Follow the feed manufacturer's guidance and seek qualified advice if you are concerned about intake or condition.
For day-to-day feeding principles, read our guide to keeping chickens.
Common questions about chicken feed estimates
Is this the amount each hen should eat?
No. The tool estimates flock-level use from your observation. It does not recommend a ration or calculate an individual bird's needs.
Why might feed disappear faster than expected?
Spillage, damp or spoiled feed, wild birds and rodents can affect what leaves a feeder or storage container. The calculator cannot identify the cause.
Why is the bag purchase estimate different from the 30-day cost?
The cost by weight is a proportional estimate of the amount used. The checkout amount counts whole bags to cover the remaining 30-day estimate after the usable stock you entered.