Roast potatoes: how much it costs to make, per portion
Roast potatoes costs £0.22 a portion in ingredients (£2.21 for a batch of 10), from UK pack prices dated 25 October 2026. To reach 68% GP, the UK food benchmark, it needs to sell for at least £0.83 including 20% VAT (£0.69 without).
Roast potatoes for a Sunday or Christmas plate: chipping potatoes peeled, par-boiled, roughed up with a little flour and roasted in rapeseed oil. Ten portions of about 200 g raw peeled weight, costed from JJ Foodservice prices read on 25 October 2026.
The lowest price is the one that just reaches 68% GP, the UK food GP benchmark (UKHospitality × Christie & Co, 2022: 65.9–69% food GP across every segment). It covers the ingredients at a normal margin, not staff, rent or energy, and most cafés, pubs and takeaways charge more for simple dishes. Check what places near you charge. GP is worked out on the ex-VAT price.
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Ingredients and cost, 10 portions
| Ingredient | Pack price | Pack size | Used | Cost |
|---|---|---|---|---|
| Potatoes (chipping), unpeeled | £16.99 | 25000 g | 2500 g | £1.70 |
| Rapeseed oil | £9.49 | 5000 ml | 250 ml | £0.47 |
| Plain flour | £12.99 | 16000 g | 30 g | £0.02 |
| Table salt | £8.99 | 12500 g | 15 g | £0.01 |
| Batch total | £2.21 | |||
| Per portion (÷ 10) | £0.22 | |||
Cost per line is pack price × (amount used ÷ pack size), the same sum the tool runs. Change one pack price and every line that uses it moves.
What it really costs: waste and staff time
| Ingredients | £0.22 |
| Waste allowance, 5% (trim, ends, the odd one binned) | £0.01 |
| Staff time: 25 min hands-on for the batch of 10 at £12.71/hr + 25% on-cost | £0.66 |
| Food, waste and staff per portion | £0.89 |
At the lowest price (£0.69 ex VAT) that is 129% of the price, before rent, energy and everything else. Many UK sites aim to keep food plus staff (prime cost) at or under 60–65% of sales. The staff line counts hands-on prep only, not unattended cooking, and uses the April 2026 National Living Wage; put your own rate, minutes and waste in the calculator's real cost section or the prime cost calculator. Every dish side by side: the UK dish cost index.
Method
- Peel the potatoes and cut into even pieces of about 60 g.
- Par-boil in salted water for 8 to 10 minutes until the edges soften, then drain and steam dry.
- Shake in the pan with the flour to rough up the edges.
- Roast in hot rapeseed oil at 200 °C for 45 to 55 minutes, turning once, until crisp.
Costing notes
The peel is costed in. The potatoes are priced at the weight bought. Hand peeling leaves about 80% (potato yield), so 2.5 kg bought gives about 2 kg peeled, 200 g a portion before roasting.
Where the prices came from
JJ Foodservice collection prices (single-unit price, no multi-buy tiers), read on 25 October 2026. Prices are as listed; JJ does not label VAT on most lines, and most raw food is zero-rated in the UK while alcohol and some ingredients carry standard-rate VAT. Your supplier's price is the one that matters: open the recipe and type it in.
- Potatoes: Chipping potatoes (POT112), 25 kg, £16.99 collection — JJ Foodservice, accessed 2026-10-25
- Rapeseed oil: KTC rapeseed oil (OIL110), 5 litres, £9.49 collection — JJ Foodservice, accessed 2026-10-25
- Plain flour: JJ plain flour (FLO016), 16 kg, £12.99 collection — JJ Foodservice, accessed 2026-10-25
- Table salt: JJ table salt (SPI019), 12.5 kg, £8.99 collection — JJ Foodservice, accessed 2026-10-25
More costed dishes: seasonal
- Pigs in blankets — £0.77 a portion
- Brussels sprouts with bacon — £0.36 a portion
- Sage and onion stuffing — £0.14 a portion
- Cranberry sauce — £0.15 a portion