Floral Preservative Calculator
Flower food and water for a set of vases, with the water volume worked out from the vase dimensions.
At a glance
- What you enter
- Vase shape, Average inside diameter, Depth of water in the vase, How many vases, Preservative dose, Times the water is changed, Water one sachet is meant for, Weight of one sachet, Price per sachet, Spare allowance for spillage and topping up
- What you get
- Water one vase holds, Water for all the vases, Water including the spare allowance, Preservative per vase, Preservative for the first fill, Sachets for the first fill, Water over the whole display, Preservative over the whole display, Sachets over the whole display, Cost of the preservative, Preservative cost per vase
- Formula shown
- Yes, every step, right below your results.
- Cost and privacy
- Free, no account needed, and nothing you type is stored.
See worked examples ↓ Read the FAQ ↓ Share this calculator ↓
Results are estimates for general information only, always verify with a professional or official source before acting on them.
How to use the Floral Preservative Calculator
- 1 Enter Vase shape, The option value is the share of a straight cylinder the vase really holds. A bulb vase of the same height and width holds far less water.
- 2 Enter Average inside diameter (cm), Measured across the middle of the water column, not at the rim of a narrow necked vase.
- 3 Enter Depth of water in the vase (cm), Two thirds full is usual. Some stems stand in shallow water.
- 4 Enter How many vases
- 5 Enter Preservative dose (g per litre), Flower food is dosed at about 5 to 10 g per litre. Use the figure printed on the pack you bought.
- 6 Enter Times the water is changed, Fresh water and a fresh dose every day or two. Three changes covers a four to six day event.
- 7 Enter Water one sachet is meant for (litres), Most sachets make 500 ml to 1 litre. Set to zero if you buy loose powder by weight.
- 8 Enter Weight of one sachet (g), Used to check the sachet count against the weighed dose.
- 9 Enter Price per sachet, Your own figure.
- 10 Enter Spare allowance for spillage and topping up (%)
- 11 Press Calculate. You get Water one vase holds, Water for all the vases, Water including the spare allowance, Preservative per vase, Preservative for the first fill, Sachets for the first fill, Water over the whole display, Preservative over the whole display, Sachets over the whole display, Cost of the preservative, Preservative cost per vase, and every intermediate step stays visible under "How is this calculated?"
- 12 Change one number at a time to see what moves the result, that is usually the most useful thing a calculator can tell you.
Worked examples
Real numbers run through this calculator. Open any example to load it into the form above and change it.
Twenty tapered vases at a wedding
A 12 cm inside diameter, 15 cm of water and a 7 gram per litre dose.
You enter
- Vase shape
- 0.85
- Average inside diameter
- 12 cm
- Depth of water in the vase
- 15 cm
- How many vases
- 20
- Preservative dose
- 7 g per litre
- Times the water is changed
- 3
- Water one sachet is meant for
- 1 litres
- Weight of one sachet
- 10 g
- Price per sachet
- $0.25
- Spare allowance for spillage and topping up
- 10%
You get
- Water one vase holds
- 1.44 litres
- Water for all the vases
- 28.84 litres
- Water including the spare allowance
- 31.72 litres
- Preservative per vase
- 10.09 g
- Preservative for the first fill
- 222.07 g
- Sachets for the first fill
- 32
- Water over the whole display
- 95.17 litres
- Preservative over the whole display
- 666.20 g
- Sachets over the whole display
- 96
- Cost of the preservative
- $24.00
- Preservative cost per vase
- $1.20
About 1.44 litres a vase, so 28.8 litres for the room and 31.7 with the spare allowance: 222 grams of powder, or 32 sachets, for the first fill and 95 sachets across three water changes.
Twenty narrow necked bottles
The same height and width, but a bottle shape that holds about a third of the water.
You enter
- Vase shape
- 0.35
- Average inside diameter
- 12 cm
- Depth of water in the vase
- 15 cm
- How many vases
- 20
- Preservative dose
- 7 g per litre
- Times the water is changed
- 3
- Water one sachet is meant for
- 1 litres
- Weight of one sachet
- 10 g
- Price per sachet
- $0.25
- Spare allowance for spillage and topping up
- 10%
You get
- Water one vase holds
- 0.59 litres
- Water for all the vases
- 11.88 litres
- Water including the spare allowance
- 13.06 litres
- Preservative per vase
- 4.16 g
- Preservative for the first fill
- 91.44 g
- Sachets for the first fill
- 14
- Water over the whole display
- 39.19 litres
- Preservative over the whole display
- 274.32 g
- Sachets over the whole display
- 40
- Cost of the preservative
- $10.00
- Preservative cost per vase
- $0.50
About 0.59 litres a vase, so 13 litres across the room and only 91 grams of powder for the first fill. The shape of the vase moves the order by more than the number of vases does.
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