Avian vets recommend pellets as 60 to 80 percent of the daily diet, with fresh vegetables making up most of the rest and seeds kept as treats. That mix matters for the budget as well as for health, because pellets and seed do not cost the same per kg. Published retail ranges put seed at about $2 to $6 per pound and pellets at about $3 to $10 per pound.
Premium pellets can cost far more than the $12 per kg default in this calculator. A 1 pound bag of Harrison's High Potency Coarse pellets costs $19.47 on Chewy, which is $42.92 per kg, while the 25 pound bag costs $233.05, which is $20.57 per kg. At $42.92 per kg, the worked example bird would cost $43.63 a month for food and treats instead of $15.80, so always enter the price of the food you actually buy rather than the default.
A seed only diet is a false saving. Seeds are high in fat and low in vitamin A, calcium and protein, and over time that can lead to fatty liver disease and vitamin deficiency, which cost far more at the vet than pellets ever will. Fresh vegetables add a small extra cost that this calculator does not count, so add your weekly produce spend to the monthly total if you want the full food bill.