Hummingbird nectar calculator
Enter your feeder size and today's high temperature. The calculator gives you the batch, the change interval and the cost.
The short answer
- The ratio is 4 parts water to 1 part sugar by volume, plain white granulated sugar, no dye and no substitutes.
- Fill each feeder only to what the birds will drink before it needs changing. A 32 oz feeder in July is a mistake, not a convenience.
- Change intervals are driven by temperature: roughly every 6 days below 71 °F, every 3 days at 85 °F, and daily above 92 °F.
- A season of nectar for two feeders costs a few dollars in sugar. There is no economic case for a commercial mix.
Enable JavaScript to use the calculator, or use the standard batch: 1 cup sugar to 4 cups water.
How the calculator works#
Two things are being worked out here, and they are usually confused with each other.
The first is batch size. A 4:1 batch is measured by volume before mixing, but dissolved sugar adds volume, so one cup of sugar plus four cups of water does not make five cups of nectar. It makes roughly four and a half. The calculator works backwards from the nectar volume you actually need, so what you get out is the amount to measure, not an approximation you have to adjust.
The second is change interval, and this is where most nectar goes wrong. Sugar water is a microbial growth medium held at ambient temperature in direct sun. The rate at which it spoils roughly doubles for every 10 °F increase, so the same feeder that is fine for most of a week in May needs changing daily in August.
| Daytime high | Change nectar every |
|---|---|
| Below 71 °F | 7 days |
| 71 to 75 °F | 6 days |
| 76 to 80 °F | 5 days |
| 81 to 84 °F | 4 days |
| 85 to 88 °F | 3 days |
| 89 to 92 °F | 2 days |
| 93 °F and above | Every day |
Fill less, more often#
The single most useful change most people can make is to stop filling the feeder. A hummingbird drinks roughly its own body weight in nectar each day, which sounds enormous until you remember it weighs about 3 grams. Two or three regular birds will not empty a 12 oz feeder in a week.
So a full 12 oz feeder in July is not a week of feeding. It is two days of feeding and five days of fermentation. Fill to a quarter or a third, change it on schedule, and the birds get fresher nectar for less sugar and less work.
If you want more birds rather than more nectar per bird, the answer is more feeders spaced out of sight of each other, because a dominant male will defend a single feeder against all comers.
What the cost line means#
The sugar figure assumes about $0.90 per pound of white granulated sugar, which is a conservative supermarket price for a large bag. At 4:1 a season of feeding two 12 oz feeders, changed on schedule from April to September, works out to a few dollars of sugar in total.
That is the whole economic argument against commercial nectar concentrate, worked through in homemade versus store-bought nectar.
Before you mix the next batch#
Clean the feeder first. Nectar poured into a feeder with residue in the ports starts contaminated, and no change interval fixes that. The routine takes two minutes: hot water, a port brush through every hole, no soap residue left behind, and a vinegar soak once a week. The full method is in how to clean a bird feeder, and the recipe with step by step quantities is in the nectar recipe page.
Frequently asked questions#
What is the correct hummingbird nectar ratio?
Four parts water to one part plain white granulated sugar, measured by volume. One cup of sugar to four cups of water is the standard household batch. That concentration is close to the sucrose content of the flowers hummingbirds feed on naturally. Stronger mixes ferment faster and are harder for a bird to process. Weaker mixes are not worth the energy of the flight.
Do I have to boil the nectar?
Boiling helps the sugar dissolve and slightly extends how long an unopened batch keeps in the fridge. It does not sterilize anything once the nectar is in a feeder that has been outdoors. Hot tap water dissolves sugar perfectly well. What actually controls spoilage is how clean the feeder is and how often you change it, not whether the water once boiled.
How long does homemade nectar keep in the fridge?
About one to two weeks in a sealed container. Discard it if it looks cloudy, smells sour or has any floating strands. Bring it to roughly outdoor temperature before filling, because cold nectar warms up and expands, which can push nectar out of an inverted-bottle feeder and start a drip.
Why is red dye a problem?
There is no evidence that hummingbirds need it and no good evidence about long-term effects of these dyes on a 3 gram animal drinking several times its body weight daily. Since the feeder itself provides all the red a bird needs to find it, the dye carries risk with no benefit. Clear nectar in a feeder with red parts works exactly as well.
Can I use honey, brown sugar or a sugar substitute?
No. Honey ferments quickly and supports fungal growth that can be fatal. Brown sugar, raw sugar and molasses contain iron, which hummingbirds tolerate poorly. Artificial sweeteners provide no calories at all, which is the entire point of the feeder. Plain white granulated sugar is chemically the closest match to flower nectar and is the only safe choice.
Sources and further reading
- Hummingbirds: Feeding Cornell Lab of Ornithology, All About Birds Nectar ratio and feeder maintenance guidance
- How to Make Hummingbird Nectar National Audubon Society Ratio, no dye, cleaning frequency