Bee Feeding Sugar Syrup Calculator

Why bees need supplemental feeding:

Bees convert nectar into honey for winter energy.
Nectar runs short at three predictable times: early spring before anything blooms, late autumn once the flow has ended, and in the middle of a drought. At any of them, feeding sugar syrup prevents starvation and keeps the colony building.

Two standard ratios:

• 1:1 (spring/stimulation): Equal parts sugar and water by weight. Mimics nectar flow and stimulates the queen to lay eggs. Used in spring to build up colony strength before the main flow.
• 2:1 (fall/winter): Two parts sugar to one part water by weight. Thick syrup is easier for bees to store and cap quickly before cold weather. Used in fall to top off winter reserves.

Formula:

Sugar (lbs) = Target volume (lbs) × Sugar ratio / (Sugar ratio + Water ratio)

Water (lbs) = Target volume (lbs) − Sugar (lbs)

Worked example: 2:1 fall syrup, 10 lbs total:

• Sugar = 10 × (2/3) = 6.67 lbs sugar
• Water = 10 − 6.67 = 3.33 lbs water

Volume conversion: a gallon of 2:1 syrup weighs about 11.0 lbs, and a gallon of 1:1 about 10.3 lbs. Those follow from the density of a sugar solution: 2:1 by weight is 66.7% sugar at roughly 1.325 g/mL, and 1:1 is 50% sugar at 1.230 g/mL.

What the syrup is worth as stores. A pound of sugar is essentially all solids, and capped stores are about 82% solids, so on paper a pound of sugar should become 1.22 lbs of stores. In practice reckon on 1 lb of sugar making 1 lb of stores, because the bees burn the difference evaporating the water back off. That is the figure the hive weight monitor uses when it tells you how much sugar a deficit needs.

How much does a colony need?

• Spring stimulation: 1–2 gallons of 1:1 over 2–4 weeks
• Fall reserves: a typical colony needs 60–90 lbs of stored honey to get through a cold-climate winter. If you are 20 lbs short, that is 20 lbs of sugar, which makes 30 lbs of 2:1 syrup, or just under 3 gallons
• Emergency winter feeding: use fondant or dry sugar. Liquid syrup raises hive humidity, and in cold weather that is more dangerous than the hunger it was meant to fix

Important tips:

• Use plain white granulated sugar only: never brown sugar, molasses, or high-fructose corn syrup
• Heat water to dissolve sugar but do not boil: boiling creates hydroxymethylfurfural (HMF), which is toxic to bees
• Add a drop of lemongrass essential oil per gallon to attract bees to the feeder
• Remove feeders when the main nectar flow starts: syrup-fed honey is not real honey

A note on the two conventions, because they get mixed up. Beekeepers say 1:1 and 2:1, meaning parts sugar to parts water by weight. Canners say light, medium and heavy, meaning sugar as a percentage of the finished syrup, and they measure in cups.
The same syrup has two names. 1:1 is 50% sugar by weight, and 2:1 is 67%, which is heavier than the heaviest syrup in the canning sugar syrup calculator. Neither page will give you the other’s answer, so start on the right one.