Everyday Money
Unit Price Comparison Calculator
Enter price and quantity for two options and see which is cheaper per unit.
Which pack is better value?
When two products use different pack sizes, the only fair fight is the same unit on both sides — kilograms, litres, sheets, washes or pods. This calculator takes price and quantity for offer A and offer B and shows which wins on unit price and by how much. Use identical units; if one pack includes extras (a free pump, a storage tin), the number will not capture that value — it only compares the figures you type. For single-product normalisation see cost per 100g and cost per 100ml. Bulk club sizes should still clear the ‘will I use it?’ test via bulk buying savings. Prefer ‘washes’, ‘sheets’ or ‘cups’ as the unit when concentrates and ready-to-use formats otherwise mislead on millilitres. If one offer is online-only, add delivery so you are not comparing a delivered price with a click-and-collect fantasy.
Worked example
Detergent A: £8 for 40 washes → £0.20 per wash. Detergent B: £11 for 60 washes → £0.183 per wash. B saves about 1.7p per wash. Over 240 washes that is roughly £4 — before you weigh scent preference and dose size. Kitchen roll A: £6 for 6 × 120 sheets. Kitchen roll B: £4.50 for 4 × 140 sheets. Per sheet, A is £6÷720≈0.83p and B is £4.50÷560≈0.80p — B edges it before softness preferences.
Limits and assumptions
Assumes you dose the same way the pack suggests. Concentrated formulas that need less product per load need ‘washes’ as the unit, not millilitres. Delivery fees can flip an online winner.
Frequently asked questions
What unit should I choose?
Pick the unit that matches how you consume the product — washes, sheets, grams or millilitres — and use it on both sides.
Can I compare three products?
Run the best two, then compare the winner with the third. The tool is built for a pairwise check.
How do free extras affect the result?
They do not appear in unit price. Mentally value the extra, or ignore it if you would not buy it alone.
Should shipping be included?
For online-only deals, add shipping into the price of that offer so the comparison stays fair.
What if pack sizes use mixed metric labels?
Convert both to grams or millilitres first. Do not compare a per-kg sticker with a per-100g mental estimate.