Keep flower contingency, stock and surplus separate
Add a chosen whole-stem reserve to each variety, subtract only usable existing stock, and track supplier pack surplus as a separate result.
Three quantities with different jobs
Recipe stems make the arrangements. Contingency stems are an explicit allowance you choose for breakage, selection or last-minute changes. Pack surplus appears because a supplier sells fixed quantities. A reserve planned before ordering and a leftover created by pack rounding are different numbers.
There is no universal reserve percentage in this calculator. The initial 10% is an editable example, not a claim about failure rates. Consider the flowers, transit, conditioning arrangements and your tolerance for shortfall. A higher number cannot guarantee usable flowers or recover an incorrect recipe.
Work through 72 roses
- Aggregate 72 recipe stems across the bouquet and table vases.
- Apply the selected 10%: 72 x 0.10 = 7.2.
- Round the reserve up to 8 whole stems. Target stock is now 80.
- Subtract 8 already available, usable stems. Net purchase need is 72.
- For 25-stem packs, order 3 packs containing 75 stems. Pack surplus is 3.
The resulting 83 stems available comprise 8 existing and 75 purchased stems. Allocate 72 to recipes, hold 8 as contingency, and expect 3 additional stems from rounding. Describing all 11 as the reserve conceals which part was deliberate.
What is usable stock?
Enter stock you can actually use for this event in the correct variety, grade, condition and length. Do not count a delivery twice by entering it as both an existing stock quantity and a future supplier order. Do not count stems already promised to another event.
For example, if a bucket contains 12 roses but four are damaged or too short, enter 8. Inspect and condition the stems before relying on them. RHS conditioning guidance explains preparing stems and removing foliage below the waterline. Its care advice is separate from the worksheet's arithmetic.
Stock can cover the entire target
If the same plan already has 100 usable roses, the target remains 80 and the purchase need becomes zero. StemOrder applies only 80 of those stock stems and purchases no rose packs. The remaining 20 existing stems are unused stock, not pack surplus. Your original stock entry stays visible in the editable table and CSV.
The reserve is rounded once per shared variety after recipe aggregation. Rounding 10% separately for twelve small arrangements would often create a larger allowance. StemOrder intentionally uses variety-level rounding so its calculation is reproducible.
After confirming stock, move to bunch rounding. If stock or the reserve changes, both supplier orders recalculate from the same net need.
Reviewed October 31, 2026. Examples illustrate the calculation method; they are not supplier quotes or universal floral recipes.