My Calculated Requirement Is 13 Kg of Wax but the Supplier Sells 10 Kg Packs — Should I Buy 20 Kg and Carry the Remainder into Next Month?

Not 20 kg — the real choice is 13 kg exact or 10 + 5 kg

If your supplier truly sold only 10 kg bags, a 13 kg requirement would force a choice between 10 kg (short by 3 kg) and 20 kg (7 kg over). CSI's container soy waxes are listed in 500 g, 1 kg, 5 kg and 10 kg bags (Natural Soy Pearl in 1, 5, 10 and 50 kg), so the realistic choices are narrower and cheaper: buy 13 kg exactly (10 kg + 3 × 1 kg, or 2 × 5 kg + 3 × 1 kg), or buy 15 kg as 10 kg + 5 kg and carry 2 kg. The 20 kg option exists, but it carries 7 kg — more than half a month's wax. On Chunks it is the dearest per kilo of every option; on CSI 464 it is the same rate as buying exactly; only Soy Pearl and CSI 468 make it cheaper per kilo, and for both the 10 kg + 5 kg round-up gets most of that saving with a third of the carry.

Which of the remaining two wins depends on the wax, because each has its own price ladder. Luxury Soy Wax Chunks is essentially flat — ₹598.00 a kilo at 500 g, ₹599.00 at 1 kg and 5 kg, ₹599.90 at 10 kg — so carrying wax buys nothing but convenience. CSI 464 is exactly flat at ₹507.40 from 1 kg to 10 kg, so 1 kg steps let you buy precisely 13 kg at the bulk rate. CSI 468 is ₹650.00 at 1 kg and ₹637.00 at 5 and 10 kg — a small step. Natural Soy Pearl is the exception: ₹450.00 at 1 kg against ₹424.80 from 5 kg, so the three 1 kg bags in an exact cover are the dear ones, and swapping them for a 5 kg bag adds 2 kg for ₹774.00.

Where does a figure like 13 kg come from? Usually from a calculation like the one in the 30-day purchase-order post: about 67 candles of 200 g at 8% with a 2% reject allowance and 3% pour loss need 12,957 g of wax — 13 kg in round numbers. This page takes the reader's 13 kg as given. If your figure already includes allowances, do not add more before rounding; the rounding itself is the last step.

Luxury Soy Wax Chunks: every option, priced

Chunks is the clearest case for the question, because its pack prices barely move. The table lists every sensible way to cover 13 kg, with the total, the effective rate per kilo, the wax carried into next month and — where wax is carried — the marginal price you pay per carried kilo compared with the cheapest exact cover.

Four facts fall out of it. The 10 kg bag is the dearest per kilo Chunks size (₹599.90), so the exact cover is cheaper as 2 × 5 kg + 3 × 1 kg than with a 10 kg bag — by ₹9.00. The 500 g bag is a rupee a kilo cheaper again, but 26 small bags save ₹13.00 at the cost of 26 bags to open, weigh and store. Every carried kilo costs ₹599.00–₹599.90 — the normal price — so carrying Chunks is never a discount. And the reader's 20 kg (2 × 10 kg) is the most expensive way to buy the extra 7 kg; 4 × 5 kg does the same for ₹18.00 less.

Soy Pearl, CSI 464 and CSI 468: three different ladders

Natural Soy Pearl rewards rounding up. The exact cover (1 × 10 kg + 3 × 1 kg) averages ₹430.62 a kilo because the three 1 kg bags cost ₹450.00 each. Replacing them with one 5 kg bag costs ₹774.00 more for 2 kg more — ₹387.00 per carried kilo, cheaper than any Soy Pearl price on the list. If Soy Pearl is your standard wax and next month needs it, 10 kg + 5 kg is the right buy. Going to 20 kg carries 7 kg at ₹414.00 a kilo — still fine on price, but now it is a cash and storage question.

CSI 464 is the opposite: flat at ₹507.40 a kilo in 1, 5 and 10 kg bags, so 10 kg + 3 × 1 kg buys exactly 13 kg at the bulk rate and every carried kilo costs the full ₹507.40. There is no reason to round up except convenience. CSI 468 sits between: the exact cover (1 × 10 kg + 3 × 1 kg) averages ₹640.00 a kilo; 10 kg + 5 kg carries 2 kg at ₹617.50 a kilo, a little under its 1 kg price. A small saving, not a reason by itself.

Should you carry the remainder into next month?

The instinct behind the question is that buying 20 kg for a 13 kg need "wastes" 7 kg. It does not, if next month needs wax too: the 7 kg is simply consumed first next month. What the carry actually costs is three things. Cash timing: ₹4,199.30 of Chunks paid 0.54 months earlier than necessary. Holding cost: at an example rate of 1.5% a month (replace it with your own cost of cash), about ₹62.99 for that month. Risk: storage space, warm-season storage, and the chance that next month's plan changes — a new wax, a slow month, a festive pause.

The three-month simulation below makes the point concrete. Each policy meets the same 13 kg a month for three months, buying only what its rule allows after using up the carried stock. The total spend barely differs for the flat-priced waxes; what differs is how much wax sits in the workshop between orders.

Because the round-up policies finish the quarter with 1 kg still in the bag, compare them on the last column: spend less the wax left at the end, valued at that wax's 5–10 kg rate. On that basis, Chunks bought only in 10 kg bags costs ₹36.00 more than buying exactly and keeps an average of 4.0 kg on the shelf; its 10-and-5 policy (which the optimiser fills with 5 kg bags, since two 5s beat one 10) comes out level. CSI 464 is level under every policy, because every kilo is ₹507.40. Soy Pearl's round-up policies come out ₹226.80 cheaper, and CSI 468's ₹117.00 cheaper, because their carried kilos are bought at the bulk rate. That is the honest answer to the title: carry the remainder when the per-kilo rate rewards it (Soy Pearl, a little for CSI 468), or when you have room and cash and want fewer orders; otherwise buy exactly.

The month's full order, with the wax bought exactly

Wax is only one line of the month. Here is the whole CSI order for the reader's 67 candles with Luxury Soy Wax CSI 464 bought exactly in 1 kg steps, two oils split 35/32, White Matte jars and Cotton Braided wicks (the wick this example's burn tests approved — CSI publishes no wick-size chart). The allowance stack follows the series' order: no test candles (approved formula), 2% rejects on consumables, 3% pour loss on wax and oil, 1% breakage on glass, then real packs. The 13 kg wax line is the reader's figure, used as given.

CSI subtotal ₹19,332.20. Swap the wax line for the other options as needed: Chunks exact ₹7,787.00, Soy Pearl 10 kg + 5 kg ₹6,372.00 (carrying 2 kg), CSI 468 exact ₹8,320.00. Cotton Braided wicks are ₹12.00 each at every pack size, so 1 × 50-pack + 2 × 10-pack is simply the smallest set of packs that covers 69. Dark Vanilla is bought as 1 × 500 g + 1 × 100 g; six 15 g bottles instead of the 100 g would cover the last grams for ₹10.00 less, which is not worth six bottles. White Matte jars come in 5s or 10s at the same ₹70.80 each.

The general rule for any awkward quantity

Thirteen kilos is one example of a requirement that falls between pack sizes. The method generalises: list every combination of real in-stock packs that covers the need, price each, compute its per-kilo rate and the marginal rate of anything it carries, and choose the cheapest exact cover unless the carried kilos are cheaper than the exact cover's own rate or you have a separate reason to hold them. The same method for 1.3 kg of fragrance oil finds that for oils the answer can flip — Saffron Cedarwood's 500 g is cheaper per gram than its 1 kg — and the minimum-pack post covers needs smaller than the smallest bag.

When a remainder is carried, write it on the next month's sheet as opening stock, so the next order nets it off. Forgetting it is how a 2 kg carry becomes an accidental 4 kg, then 6 kg. The reorder sheet has a column for exactly this, and per-material reorder points decide when the next wax order goes out. For the requirement side, combining 20 SKUs into one monthly wax figure and consolidating one monthly order show how the 13 kg is built.

This page sits in the procurement cluster that ends with the complete procurement system, where pack-size selection is the step between supplier minimums and the purchase order. Safety stock by material role explains why a shared wax may deserve a deliberate buffer — which is a better reason to hold extra kilos than a rounded-up bag.

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