Free tool
Vegetable yield calculator
Pick a crop and tell us how much you're growing — by plant count, bed area or row length — and we'll estimate the harvest you can expect in kilograms.
Different types crop differently — pick the closest.
Estimated harvest from tomato
18 kg
across the whole season
Plants
6
as entered
Side servings
225
≈ 80 g portions
Per-plant assumption
3 kg
Typical UK home-grow average for tomato, per plant
Estimates are guidance for UK home gardens — real yields swing with weather, variety, soil and watering. ‘Side servings’ turns the harvest into roughly how many adult side-dish portions it makes (about 80 g of tomato each), to help you picture the crop rather than as a precise meal plan.
How to use it
Choose your crop from the list, then pick how you want to describe the amount you're growing. Enter a straight number of plants if you already know it, a bed area in square metres if you're filling a raised bed, or a row length in metres for a traditional row. Where a crop comes in distinct types — tomatoes as cherry, plum or beefsteak, potatoes as earlies or maincrop — pick the closest from the type / variety list and the per-plant figure adjusts. The estimated harvest updates as you type — there's nothing to press. The result shows the total weight in kilograms, how many plants that works out as, the per-plant figure we used, and roughly how many adult side servings that makes.
How the calculation works
For bed area we work out a realistic plants-per-square-metre from each crop's spacing — the gap between plants in the row multiplied by the gap between rows — so a row crop such as beetroot comes out around 50 plants per m² rather than the much denser figure you'd cram into an intensive square-foot grid. For a row, we divide the length by the plant spacing in centimetres. Either way, we multiply the number of plants by a realistic UK home-grow yield per plant — for example around 3 kg for a tomato or courgette, 1 kg for a maincrop potato, and a few hundred grams for leafy crops. The side servings line divides the harvest by a typical adult side portion for that crop (about 80 g of carrots or beetroot, 200 g of potatoes, a small handful of herbs) so you can picture the haul as meals. These are averages for planning: a good year, a sheltered plot or a vigorous variety can beat them, while a cold, wet summer or a slug invasion will fall short. Keep your own records to fine-tune year on year.
Frequently asked questions
- How much can I expect to harvest from one tomato plant in the UK?
- A healthy outdoor or greenhouse tomato plant in the UK typically gives around 3 kg of fruit across a season, though a well-fed cordon in a warm spot can do more. This calculator uses 3 kg per plant as a realistic average — multiply by the number of plants you're growing for a rough total.
- Why is the yield only an estimate?
- Real harvests vary hugely with the weather, your soil, the variety you chose, how consistently you water and feed, and pest pressure. The per-plant figures here are sensible UK home-grow averages for guidance — treat them as a planning ballpark, not a promise, and keep your own notes year to year.
- How do I work out yield from a bed area or row length?
- Switch the toggle to 'Bed area' and enter your bed size in square metres, or 'Row length' and enter the length in metres. The tool works out how many plants fit using each crop's spacing, then multiplies by the per-plant yield. It's the quickest way to see what a raised bed or a single row will actually produce.