I remember when I started tracking protein… and my grocery bill quietly doubled. I was buying chicken breast like it was going out of fashion, because “chicken is the healthy choice”. Then one evening I did the actual maths on a tub of whey protein versus the chicken, and felt like an idiot. Per gram of protein, the whey was less than half the price. I had been paying a premium for my assumptions.
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The Protein Cost Calculator above stops that happening to you. Pick a food preset with typical UK supermarket values — or enter your own pack price, weight and protein content — and it tells you the cost per 100 grams of protein, how many grams you get per £1, and what each 30-gram serving really costs.
The number that matters: cost per 100 g of protein
Pack prices lie. A £4.50 pack of chicken and a £1.40 tin of tuna cannot be compared until you convert both to the same unit: pounds per 100 grams of actual protein. Water weight, bones and branding all disappear in that conversion, and the ranking that comes out surprises almost everyone.
| Food (typical UK buy) | Pack | Protein/100 g | Cost per 100 g protein |
|---|---|---|---|
| Whey protein powder | £24.99 / 1 kg | 80 g | £3.12 |
| Eggs | £2.20 / 600 g | 13 g | £2.82 |
| Tinned tuna | £1.40 / 145 g | 24 g | £4.02 |
| Chicken breast | £4.50 / 600 g | 31 g | £2.42 |
| Greek yoghurt | £1.75 / 500 g | 10 g | £3.50 |
| Tofu | £1.80 / 396 g | 8 g | £5.68 |
Eggs winning surprises people, but there it is — humble, cheap, and nutritionally excellent. The British Nutrition Foundation has good material on protein sources if you want to compare more than just price.
The cost formula
First find the total protein in the pack, then divide the price by it. With price in pounds, weight in grams and p as protein per 100 g:
| Variable | What it is | Example |
|---|---|---|
| Price | What the pack costs you | £4.50 |
| Weight | Pack weight in grams | 600 g |
| p | Protein per 100 g, from the label | 31 g |
The calculator also flips it around into grams of protein per £1, which I find the most intuitive comparison when standing in the aisle. The NHS Eat Well guide reminds us that price is only one axis — variety across protein sources matters for the rest of your nutrition too.
A worked example: chicken breast versus whey
Let me walk you through my exact setup — the comparison that changed my shopping. Chicken breast at £4.50 for 600 g (31 g protein per 100 g) against whey at £24.99 for 1 kg (80 g per 100 g).
| Step | Chicken breast | Whey powder |
|---|---|---|
| Total protein in pack | 600 × 0.31 = 186 g | 1000 × 0.80 = 800 g |
| Cost per 100 g protein | 4.50 ÷ 186 × 100 = £2.42 | 24.99 ÷ 800 × 100 = £3.12 |
| Protein per £1 | 41.3 g | 32.0 g |
| 30 g servings per pack | 6 at £0.75 | 26 at £0.96 |
Plot twist: at these particular prices the chicken actually wins. That is exactly why I built the calculator instead of memorising a ranking — supermarket prices move constantly, and the “cheapest” answer changes with the offers. Run your own receipt through it.
Using the Protein Cost Calculator step by step
Pick a preset (or choose Custom), check the figures against your pack, then press Compare cost.
| Input field | What to enter | Sample figure |
|---|---|---|
| Food preset | Prefills typical UK values | Chicken breast |
| Pack price (£) | What you actually paid | 4.50 |
| Pack weight (g) | From the label | 600 |
| Protein per 100 g (g) | From the nutrition panel | 31 |
You get the cost per 100 g of protein, grams per £1, the number of 30-gram servings in the pack and the cost per serving. Everything runs in your browser. Once you know your cheapest sources, the Protein Per Meal Planner builds them into your day, and the Protein Intake Calculator tells you the daily total you are shopping for. For the calorie budget behind it all, see the TDEE Calorie Calculator.
Where the real savings hide
Frozen beats fresh. Frozen chicken breast and frozen fish are usually 20–30% cheaper per kilo with identical protein. I buy fresh for taste, frozen for the budget.
Own-brand whey. The supplement markup on branded tubs is enormous. Supermarket or bulk own-brand whey is the same 80% protein for far less.
Eggs, always eggs. Nothing I have found beats eggs for cheap complete protein. If your diet allows them, they should be a staple, not a backup.
One caution: do not let price be the only vote. I still eat salmon knowing it is expensive per gram — the omega-3s earn their place. Cheap protein is a tool, not a religion.
Questions I get asked about protein costs
What is the cheapest protein in the UK?
In my experience, eggs and value chicken breast usually win, with own-brand whey close behind — but it depends entirely on current supermarket prices, which is why I compare per 100 g of protein rather than per pack. Run your own regular buys through the calculator above; the ranking changes with the offers more than you would expect.
Is whey protein cheaper than chicken?
Sometimes, not always. At typical prices they are surprisingly close per gram of protein — my worked example above had chicken slightly ahead. Whey wins on convenience and shelf life; chicken wins on being actual food. I use both: chicken for meals, whey for the gaps.
How much does 100 g of protein cost per day?
Using cheap sources like eggs, chicken and whey, roughly £2.50 to £3.50 a day for 100 grams of protein. Premium sources — fresh salmon, steak, branded snacks — can easily double that. Over a month, the difference between the cheapest and dearest way to eat 140 g a day is well over £100.
Are protein bars worth the money?
Almost never, on a per-gram basis. They are confectionery with a marketing budget — typically three to four times the cost per gram of whey. I keep one in my gym bag for emergencies, but as a daily source they are the most expensive protein in the shop. A shaker and a scoop cost less and do more.
