How Many Flowers Do You Need? A Calculator Built by Florists

How This Calculator Came About

I was having coffee with Anna at Kingscliff last week. She's been with us 15 years now, started as our florist when we ran the office out of our garage in Pottsville, then moved into bookkeeping when we went fully online. We still catch up regularly, partly work, partly just habit after all this time. She mentioned something that had been bugging her. The customer service team in Armidale kept fielding the same question, over and over. I have a vase, it's about this wide, how many roses do I need? Or, I bought a dozen stems but my vase looks empty, what went wrong?

Anna grabbed a napkin and started sketching vase shapes. She looked up and said something that stuck with me. "It's not the number of flowers that matters. It's the relationship between the stem, the opening, and the shape. Get that wrong and you've either got flowers drowning in space or crammed in so tight they can't breathe."

So we built this. Not to be clever, just to answer a question we've been asked hundreds of times.

Why Vase Shape Changes Everything

"People think a vase is a vase," Anna says, Qualified Florist with over 15 years experience. "But a narrow neck vase with a 5cm opening physically can't hold the same arrangement as a cylinder with a 12cm opening. The neck acts like a funnel. You might only fit 6 stems through, but they fan out beautifully above. A mason jar or cylinder needs more stems to fill the visual space or it looks sparse."

She's right. We learned this running our shop on Marine Parade back in 2007. Customers would buy 6 roses, take them home, put them in a wide vase, then call back disappointed. The flowers were fine, the vase was fine, but the combination was wrong. There's maths to this, actual geometry, and once you understand it the guesswork disappears.

The calculator above adjusts for three vase profiles. A cylinder gives you the baseline, a narrow neck reduces the count because stems bunch at the entry point, and a wide opening like a mason jar needs more stems to avoid that lonely, scattered look.

Stem Thickness Matters More Than You Think

"A tulip stem and a hydrangea stem are completely different beasts," Anna told me, stirring her flat white. "Tulips, carnations, gerberas, they have thinner stems, maybe 4 to 6mm. You can pack more into the same opening. But hydrangeas, lilies, some of the larger native stems, they're 10 to 15mm thick and woody. Three hydrangea stems fill a vase the same way seven roses would."

This is one of those details you only learn by handling thousands of flower arrangements. Back in our Kingscliff flower shop days, a customer once ordered a dozen mixed natives for her mum in Tweed Heads. She was upset when the arrangement looked "small" compared to a dozen roses she'd ordered previously. Same dozen stems, completely different visual result. The native banksia and protea stems were three times the thickness of rose stems. We ended up adding extra foliage, on us, because we hadn't explained the difference properly upfront.

That's why the calculator has a stem thickness option. Thin stems like carnations pack tighter, so you need more of them. Thick stems like lilies and hydrangeas take up more real estate, so fewer stems fill the space.

The Three Looks Explained

The calculator gives you three numbers: minimal, classic, and lush. Here's what those actually mean in practice.

Minimal is the fewest stems you can get away with before the arrangement starts looking accidental. Anna describes it as "architectural" which is a kind way of saying sparse but intentional. Good for modern interiors, not so good if you're trying to impress your mother in law.

Classic is what our partner florists aim for in most standard arrangements. Enough density that the flowers support each other, enough space that each bloom has room to open fully. "This is where flowers look like flowers," Anna says, "not a crowded train carriage and not a lonely bus stop."

Lush is for when you want that overflowing, abundant look. Birthday celebrations, anniversaries, or when you really need to apologise for something. More stems means more visual impact but also more cost, so we wanted to give people an honest picture of what each option requires.

A Note on Foliage

The calculator assumes you're working with stems only. Most arrangements from our partner florists include foliage like eucalyptus, leather fern, or ruscus, which fills gaps and adds texture. If you're buying stems from a market or supermarket and arranging them yourself, consider adding greenery. It makes a smaller number of stems look fuller without buying more flowers.

"Foliage is the secret weapon," Anna says. "Three stems of eucalyptus can transform 8 roses into something that looks like 12. Our florists know this instinctively, but home arrangers often skip it and wonder why their vase looks bare."

Why We Built This

We've been sending flowers since 2009. Over 800 partner florists across Australia. Thousands of arrangements every week. And still, one of the most common questions we get is some version of "how many flowers do I need?" We figured if we kept answering it manually, we might as well build something that answers it properly.

If you're ordering through us, our florists handle all of this for you. They know exactly how many stems to use for the vase or box they're working with. But if you're arranging flowers at home, or trying to figure out what size bunch to order for a specific vase, this should help.

Questions? Call us on 1300 360 469, we're here Monday to Friday 7am to 6pm and Saturdays 7am to 12.30pm. All Australian, all based here, no offshore call centres.

About the Authors

Siobhan and Andrew founded Lily's Florist in 2009 after buying a small flower shop in Kingscliff, NSW. What started as a single shopfront is now a network of 800+ partner florists across Australia. Anna joined the team 15 years ago as a qualified florist and helped build the partner network before moving into operations as our guru bookkeeper. This calculator came from a coffee catch-up in Kingscliff (actually Cudgen and the new Farm & Co Café') and about a decade of answering the same customer question.