How much fondant to feed bees in winter
I found no standard fondant amount per hive. The sources give examples: a 1 kg packet, or 1–5 kg blocks sized to last until the next visit. This page does that sizing sum. Enter the weeks until you will look again and how much a colony eats in a week.
What the sources say
The Apiarist's Winter weight (David, February 2022) says hive weight is a good stand-in for stores when little nectar comes in, and that he checks every 2–3 weeks. He adds fondant in 1–5 kg blocks, depending on colony size, when he expects to be back, and whether nectar is likely before then. He says he errs on the side of generosity. He cites Tom Seeley's studies for colony weight loss in maintenance mode of perhaps 1 kg per week, rising once brood rearing starts in earnest. That is a weight loss, which includes honey eaten, so it is only a rough guide to fondant. I use it as the default above.
Douglas Gucker at Illinois Extension (January 2026) put a 2.2 lb (1 kg) packet of commercial fondant on a hive before Thanksgiving, above two nearly full honey supers. By January the packet was nearly eaten. He advises adding supplemental feed at least monthly through the end of March. The post says research puts a central Illinois colony's winter need at 60 to 90 pounds of capped honey.
A worked example
You lift the hive on Nov 15 and it feels light, and you plan to look again in 3 weeks. At 1 kg a week that is 3 × 1 = 3 kg, or 6.6 lb of fondant: three 1 kg packets. Visiting every 2 weeks, it is 2 kg. If the packet is gone sooner than the sum says, shorten the interval. The Illinois hive went through one packet between Thanksgiving and January with honey still above it.
The sum assumes the bees eat only fondant. A hive with honey in reach eats some of that too, so I'd treat the answer as the most one visit needs. To turn a honey gap into pounds of sugar, use how much sugar to feed for winter. The check-by date for your own hive is on how long winter honey stores last. A solid board is another route, see the candy board recipe.
If the hive is light now, syrup is still an option while it is warm enough. See the fall feeding cutoff page for the temperatures two sources use.