Buy a flower frog that is too big and it will not fit your vase. Buy one that is too small and it will not hold enough stems or stand up to a heavy branch. The good news is that the right size follows a simple rule, and this guide gives you the chart, the stem counts and some examples for common vases.
Want the answer for your exact vase? Use the free Flower Frog Size Calculator. Enter your vase and your flowers and it returns the frog size, the type of frog, how many stems it holds and how tall to cut them.
How to measure your vase
- Empty the vase and dry it. Measure straight across the opening from inside rim to inside rim.
- Measure straight across the inside base, at the bottom, from inside wall to inside wall. For a bowl that curves in, measure the flat part where the frog will actually sit.
- Measure the height from the inside bottom to the rim.
- For a narrow-neck vase, note the width of the neck as well, since the frog has to pass through it.
Enter those numbers in the Flower Frog Size Calculator. If you prefer centimeters, switch the unit and the results change to the usual metric frog sizes.
The basic rule
Choose a frog about one third to one half of the width of the inside base of your vase. Smaller arrangements suit the lower end of that range and fuller ones suit the upper end. Frogs are sold in a handful of standard sizes, roughly 1 to 5 inches (25 to 125 mm) across, so round to the nearest one.
Measure the inside of the vase at the bottom, not the outside. Thick glass or a heavy ceramic base can reduce the usable space by half an inch or more.
Flower frog size chart
| Vase inside base | Frog size range | Typical pick |
|---|---|---|
| 2 in (5 cm) | 1 in (25 mm) | 1 in |
| 3 in (8 cm) | 1–1.5 in (25–40 mm) | 1.5 in |
| 4 in (10 cm) | 1.5–2 in (40–50 mm) | 1.5 in |
| 5 in (13 cm) | 1.5–2.5 in (40–65 mm) | 2 in |
| 6 in (15 cm) | 2–3 in (50–75 mm) | 2.5 in |
| 7 in (18 cm) | 2.5–3.5 in (65–90 mm) | 3 in |
| 8 in (20 cm) | 2.5–4 in (65–100 mm) | 3.5 in |
| 10 in (25 cm) | 3.5–5 in (90–125 mm) | 4 in |
| 12 in (30 cm) | 4–5 in (100–125 mm) | 5 in |
For a base wider than about 8 inches and a large arrangement, two or three smaller frogs side by side anchor the stems better than a single big one.
How many stems does a flower frog hold?
The number depends on the area of the frog and the thickness of the stems. As an estimate for a pin frog, we allow about 0.15 square inches of frog per thin stem, 0.35 per medium stem and 0.75 per thick or woody stem. That gives these approximate capacities:
| Frog size | Thin stems | Medium stems | Thick or woody stems |
|---|---|---|---|
| 1 in (25 mm) | ≈ 5 | ≈ 2 | ≈ 1 |
| 1.5 in (40 mm) | ≈ 11 | ≈ 5 | ≈ 2 |
| 2 in (50 mm) | ≈ 20 | ≈ 8 | ≈ 4 |
| 2.5 in (65 mm) | ≈ 32 | ≈ 14 | ≈ 6 |
| 3 in (75 mm) | ≈ 47 | ≈ 20 | ≈ 9 |
| 3.5 in (90 mm) | ≈ 64 | ≈ 27 | ≈ 12 |
| 4 in (100 mm) | ≈ 83 | ≈ 35 | ≈ 16 |
| 4.5 in (115 mm) | ≈ 106 | ≈ 45 | ≈ 21 |
| 5 in (125 mm) | ≈ 130 | ≈ 56 | ≈ 26 |
These are editorial estimates, not tested figures, and real frogs vary. Treat the counts as a comfortable ceiling rather than a target; a loose arrangement looks better with fewer stems than the frog could technically hold.
Examples for common vases
- 4 inch bud bowl, a few thin stems. A 1.5 inch pin frog is plenty. It holds about 11 thin stems, far more than a bowl this small needs.
- 6 inch shallow bowl, medium arrangement. A 2.5 inch pin frog fits well and holds about 14 medium stems. A 3 inch frog gives a little more room.
- 8 inch low dish, ikebana style. A 3 to 3.5 inch pin frog, set slightly off-centre, is a classic choice.
- 10 inch centerpiece bowl, large arrangement. Consider two 3.5 inch frogs placed side by side, which together hold about 54 medium stems.
- Narrow-neck vase with a 3 inch opening. The frog has to pass through the opening, so choose one no larger than the opening minus a quarter of an inch, which here means 2.5 inches or smaller. A frog lid (a grid top) is a good alternative.
Common sizing mistakes
- Measuring the outside of the vase. Glass and ceramic walls can be thick, so the inside is smaller than it looks.
- Ignoring the neck. In a narrow-neck vase, the opening limits the frog, whatever the base size is.
- Buying one huge frog for a very wide bowl. Two or three smaller frogs are easier to place and hold the stems better.
- Counting stems at the ceiling. A frog can hold many stems on paper, but an arrangement looks best with space between them.
- Forgetting weight. A light frog may be the right size and still tip under a heavy branch.
Beyond size: weight and type
Size is only half the story. A heavy brass or stainless steel pin frog is steadier than a light one, which matters for tall branches and big arrangements. Thick, woody stems do best on a heavy pin frog or a cage frog, while thin, soft stems are happy on a grid frog. Choose a coated or stainless frog if you want to avoid rust. For a full overview of the types, read Flower Frog Vases: What They Are, Types & How to Choose.
Getting it to stay put
Whatever size you buy, secure it with floral putty on a dry base before adding water. Our guide to how to use a flower frog walks through the whole process, and if you are weighing frogs against foam, see flower frog vs floral foam.
Frequently Asked Questions
What size flower frog do I need for a 6 inch bowl?
About 2 to 3 inches. A 2.5 inch pin frog is a good middle choice for a medium arrangement.
How many stems does a 2 inch flower frog hold?
As an estimate, a 2 inch pin frog holds about 20 thin stems, 8 medium stems or 4 thick, woody stems.
Can a flower frog be too big for the vase?
Yes. A frog that is wider than about half the inside base leaves little room for water and stems to spread, and in a narrow-neck vase it may not fit through the opening at all.
