A 14.5 oz can of tomatoes holds about 1 3/4 cups. That is the whole contents of the can — tomatoes and their juice — poured into a measuring jug. The figure is approximate rather than exact, because a can is sold by weight and the volume depends on how the tomatoes are cut: diced tomatoes pack differently from whole ones, and crushed tomatoes settle differently again. But for cooking purposes 1 3/4 cups is the number to use, and it is the figure the can size works out to: 14.5 fluid ounces is just over 1 3/4 cups, and the solids take up a little of that space.
This matters because most recipes are written in cups while tomatoes are sold in cans, and the mismatch causes real cooking errors. A sauce recipe that calls for 3 1/2 cups of tomatoes needs exactly two 14.5 oz cans; one can leaves the sauce thin and under-seasoned, three cans drown it. Chilli recipes are the classic case — they usually call for two cans, and knowing each can is 1 3/4 cups lets you scale the recipe up or down without guessing. Keep this number in mind and you will stop opening a second can halfway through cooking.
Can of tomatoes conversion table
The table below breaks a 14.5 oz can down into fractions, so you can measure out half a can for a small sauce or work out how many cans a big batch needs. All volumes are for the whole contents of the can, juice included.
| Amount | Cups (approx.) | Tablespoons | Fluid ounces |
|---|---|---|---|
| 1/4 can | 0.44 cups (about 1/2 cup) | 7.0 tbsp | 3.5 fl oz |
| 1/2 can | 0.88 cups (about 7/8 cup) | 14.0 tbsp | 7.0 fl oz |
| 3/4 can | 1.31 cups (about 1 1/4 cups) | 21.0 tbsp | 10.5 fl oz |
| Full can | 1.75 cups (about 1 3/4 cups) | 28.0 tbsp | 14.0 fl oz |
| 2 cans | 3.50 cups (about 3 1/2 cups) | 56.0 tbsp | 28.0 fl oz |
The can weighs 411 g in total (14.5 oz). That weight includes the juice, so do not use 411 g as the weight of the drained tomatoes — the drained weight is lower and varies with how the tomatoes were cut.
Worked examples
A marinara sauce for six
A marinara recipe calls for 3 1/2 cups of crushed tomatoes, simmered with garlic, olive oil and basil. Two 14.5 oz cans give you exactly 3 1/2 cups, so open both, pour them in, and crush any whole pieces against the side of the pan with a wooden spoon. Simmer for 25 to 30 minutes until the sauce thickens and the oil separates at the edges. If you only have one can, halve the rest of the recipe — half the garlic, half the oil, half the basil — rather than making a thin sauce with the full seasonings.
Chilli that serves eight
A chilli recipe for eight people uses two cans of diced tomatoes, which is 3 1/2 cups, along with beans, mince and spices. If you are cooking for four instead, use one can — 1 3/4 cups — and halve everything else. The tomatoes go in after the mince has browned and the spices have bloomed in the oil, and the juice from the can is part of the cooking liquid, so do not drain it. If the chilli looks too wet after 45 minutes, take the lid off for the last 15 minutes so the liquid reduces.
A soup that needs one cup
A vegetable soup recipe calls for 1 cup of diced tomatoes, and you have a full can. Pour the can into a measuring jug, take out 1 cup, and keep the remaining 3/4 cup in a small container in the fridge — it will keep for two to three days and is the right amount for a shakshuka base, a small pan of beans, or a quick tomato and garlic pasta. Do not store leftover tomatoes in the opened can: the acid reacts with the metal and gives the tomatoes a metallic taste, and the open edge is a cut risk in the fridge.
How the figure is worked out
There is no weighing involved in the headline answer — it is arithmetic on two published numbers. The package weight is a standard 14.5 oz can, the most common size for diced, whole and crushed tomatoes. The cup weight comes from the ingredient table, and dividing one by the other gives the cups in the package. That is also why the answer is approximate: scoop a cup differently and the grams per cup change, so the cups per bag move with it. For anything where the amount truly matters, weigh the ingredient instead of counting cups.
Practical guidance
Always check the can size before you start cooking. The 14.5 oz can is the standard, but tomatoes also come in 28 oz cans, which hold about twice as much, and in small 8 oz cans. The label is the authority — if it says 14.5 oz, use 1 3/4 cups; if it says something else, scale from that figure rather than assuming. Diced, whole, crushed and stewed tomatoes in the same size can all hold about the same volume, so you can swap between them freely for volume, though the texture changes: whole tomatoes need crushing, diced tomatoes hold their shape in a chunky sauce, and crushed tomatoes cook down fastest.
Do not drain the can unless the recipe says so. The juice is not water — it is tomato liquid with flavour and a little salt, and it counts towards the cooking liquid in most recipes. If a recipe calls for drained tomatoes, the volume after draining will be less than 1 3/4 cups, and you should measure after draining rather than trusting the can figure. Store any opened can contents in a glass or plastic container in the fridge and use within two to three days, or freeze the rest in a bag for up to three months.
Frequently asked questions
How many grams are in a can of tomatoes?
A 14.5 oz can weighs 411 g in total, including the juice. That is the weight printed on the label. The drained weight is lower and depends on the cut — diced tomatoes drain differently from whole ones — so weigh the tomatoes after draining if your recipe works in grams and calls for drained tomatoes.
Is a 14.5 oz can the same as 1 3/4 cups for all tomato types?
Approximately, yes. Diced, whole, crushed and stewed tomatoes in a 14.5 oz can all measure about 1 3/4 cups with their juice. Whole tomatoes may measure a fraction less because of air gaps between them, and crushed tomatoes may measure a fraction more because they settle, but the difference is small enough not to matter in a cooked sauce.
Can I substitute a can of tomatoes for fresh tomatoes?
Yes, in cooked dishes. One 14.5 oz can replaces roughly the same volume of chopped fresh tomatoes in a sauce, soup or stew, but the flavour is different: canned tomatoes are picked and packed ripe, so they are often more consistently flavoured than out-of-season fresh tomatoes. Do not use canned tomatoes raw in a salad — the texture is wrong.
Should I drain a can of tomatoes?
Only if the recipe says so. Most sauces, soups and chillis use the juice as part of the cooking liquid. Drain them when you need the tomato solids without extra liquid — for example in a pizza topping, a bruschetta, or a filling where excess liquid would make the dish soggy. Keep the drained juice for a soup base rather than throwing it away.
How long do opened canned tomatoes keep?
Two to three days in the fridge, in a non-metal container. Transfer the leftovers out of the can as soon as you open it, because the acid in the tomatoes reacts with the exposed metal. For longer storage, freeze them in a sealed bag or container for up to three months, and thaw in the fridge overnight.