Compare pack sizes without losing sight of the total
A smaller shelf price does not always mean a better value. A 500 g bag and a 1 kg bag contain different amounts, so compare their prices per 100 g before choosing. This calculator also shows how much you would actually pay for each order. Enter the price, individual size, and unit for products A and B. Open the optional product C section if you have a third alternative. Fields start empty; the faint placeholder numbers are examples and are not used as actual input.
How to enter a multipack
The price is the price of one complete pack. If a pack contains two 500 g bags, enter 500 g as the individual size and 2 as the items in one pack. If you intend to buy three of those packs, enter 3 as the number of packs to buy. Alternatively, you could describe a whole pack as 1 kg with 1 item per pack. Do not use 1 kg and 2 items together for that same pack: that would count the quantity twice. Blank pack options default to one item and one pack.
Formulas and comparison units
- Total quantity = individual size × items per pack × packs to buy.
- Checkout total = price per pack × packs to buy × (1 − discount ÷ 100) + delivery per order.
- Unit price = checkout total ÷ total quantity in the base unit × reference quantity.
- Saving with the lowest = (this unit price − lowest unit price) ÷ this unit price × 100.
Mass is converted to grams and displayed per 100 g. Volume is converted to milliliters and displayed per 100 ml. Count is displayed per item. One kilogram is 1,000 grams, and one liter is 1,000 milliliters. Weight and volume cannot be mixed without a density, which this tool does not assume. Item counts are comparable only when the items offer comparable sizes or uses; a short roll and a long roll are not automatically equivalent.
Worked example: a lower unit price can need more cash
Suppose example product A costs 3.00 for 500 g and product B costs 4.80 for 1 kg, in the same currency, with no discount or delivery charge. A costs 0.60 per 100 g; B costs 0.48 per 100 g. B is 20% cheaper per 100 g than A. However, the checkout totals are still 3.00 for A and 4.80 for B. If you need only a little, have limited storage, or might waste the remainder, the larger pack may not be the best purchase.
Discounts, delivery, and taxes
The discount applies once to the goods subtotal, before delivery. Buying three packs at 10.00 each with a 10% discount and 3.00 delivery gives 30.00 × 0.9 + 3.00 = 30.00. Free-delivery thresholds, fixed-value coupons, stacked offers, reward points, taxes, and currency conversion are not calculated. Use prices in the same currency and with the same tax treatment. If a deal has other rules, enter an adjusted price and use a zero discount. If delivery is shared with unrelated items, decide which share belongs to this comparison.
Limits and rounding
Prices and delivery charges must be between zero and one trillion. Individual size must be between 0.000000001 and one trillion. Pack counts must be whole numbers from one to one million. Values that are too large to compare reliably are rejected. Displayed numbers are rounded, while the comparison uses the underlying values. Very small differences may not be visible in the rounded display. Free products have a unit price of zero; if every product is free, the reported saving is zero rather than an undefined percentage.
Calculations update in your browser. The copy-link button creates a link containing your inputs, so check the values before sharing it. The calculator does not retrieve current shop prices, verify stock, or confirm that an offer is available.
Frequently asked questions
Is the price for one item or the whole pack?
Enter the price of one whole pack. For two 500 g bags sold together for 6, enter price 6, individual size 500 g, and 2 items per pack. If you buy three such packs, enter 3 packs to buy.
Can I compare grams with milliliters?
No. Grams measure mass and milliliters measure volume. A density is needed to convert between them. This tool compares g with kg, ml with L, or item counts with item counts.
Does the discount apply to delivery?
No. The percentage discount applies to the goods subtotal only. Delivery is added once per product order after the discount. For other coupon rules, enter an already adjusted pack price and leave the discount blank.
Does the lowest unit price mean the lowest checkout total?
No. A larger pack may cost less per 100 g but require a larger payment. Check both the unit price and checkout total, as well as how much you can use.