Ran out of tomato sauce mid-recipe? Tomato paste will do the job at 3 tbsp tomato sauce, simmered down, per 1 tbsp paste — but only if you also adjust for what the swap takes away or adds. Condiments and tomato products swap by concentration and flavour, not just by volume. A paste is far more concentrated than a sauce, a sweetened ketchup is a different ingredient from an unsweetened paste, and two brown sauces that look alike on the spoon can taste nothing alike in the pan. This page gives the ratio, shows it in a table for the amounts you will actually meet, and walks through three real dishes so you can see where the swap works and where it changes the dish into something else.
The ratio, in a table
The table below converts tomato sauce to tomato paste for the amounts you are most likely to meet. The rule is always the same: 3 tbsp tomato sauce, simmered down, per 1 tbsp paste.
| Tomato sauce called for | Tomato paste to use |
|---|---|
| 1 tbsp | 3 tbsp, simmered down |
| 2 tbsp | 6 tbsp, simmered down |
| 3 tbsp | 9 tbsp, simmered down |
| 1/4 cup | 3/4 cup, simmered down |
| 1/3 cup | 1 cup, simmered down |
| 1/2 cup | 1 1/2 cups, simmered down |
By weight, one cup of tomato sauce is about 245 g (spooned and levelled, USDA) and one cup of tomato paste is about 262 g (spooned and levelled, USDA). The two weigh very differently per cup, so measure this swap by volume, not by weight, unless you are converting the whole recipe to grams — and then use the numbers above. All weights on this page are approximate; verify with a kitchen scale when the result matters.
Worked examples
Example 1: Slow-cooked ragù
A recipe for a ragù calls for 2 tbsp of tomato paste. Using the ratio, that becomes 6 tbsp of tomato sauce, simmered down. Put the sauce in a wide pan, simmer it until it has reduced by about two-thirds and it coats the back of a spoon, then add it to the ragù. The sauce will be rich and deep, close to the original.
Example 2: Chilli con carne
A recipe for chilli calls for 1 tbsp of tomato paste. Using the ratio, that becomes 3 tbsp of tomato sauce, simmered down. Reduce the sauce in a small pan while the onions cook, then add it to the pot. The chilli will have the depth it needs, though a touch less intense than the paste version.
Example 3: Braised beef
A recipe for braised beef calls for 3 tbsp of tomato paste. Using the ratio, that becomes 9 tbsp of tomato sauce, simmered down. Reduce the sauce first, then fry it briefly in the pot with the onions before adding the beef and the braising liquid. The braise will be rich and savoury.
What changes in the result
Tomato sauce in place of tomato paste needs three times as much, and it needs to be simmered down. Tomato paste is concentrated cooked tomato — the water has been cooked out of it — while tomato sauce is thin and mostly water, so a tablespoon of paste holds the tomato flavour of three tablespoons of sauce. The ratio is three tablespoons of sauce, simmered down, per tablespoon of paste. Simmer the sauce in a wide pan until it has reduced by about two-thirds and it coats the back of a spoon, and only then use it as paste. The result is close to the original in flavour, though a little less intense, and it takes time — this is a swap for a slow-cooked dish, not a quick one.
When not to substitute
Do not make this swap where the dish needs paste quickly. Reducing sauce takes time — a wide pan, a gentle simmer, and regular stirring — and a recipe that needs paste in five minutes will not wait for it. Do not use the sauce without reducing it either: three tablespoons of unreduced sauce will make the dish watery and weak, and the flavour will be thin. And do not use a heavily seasoned sauce: a sauce with herbs, garlic and salt will carry those flavours into the dish, where paste is neutral and lets the recipe season itself.
Practical guidance
Taste as you go, and add the substitute in stages rather than all at once — it is easy to add more of a salty, sweet or sharp condiment and impossible to take it out. When a recipe calls for a concentrated tomato product, fry the substitute in a little oil for a minute before adding liquid: cooking it briefly deepens the flavour and takes off any raw edge. Balance a sweet swap with a splash of vinegar or lemon juice, and balance a sharp swap with a pinch of sugar. Keep opened jars and bottles in the fridge, label them with the opening date, and freeze leftover tomato paste in tablespoon-sized portions so you never have to open a new tube for a single spoonful. All amounts on this page are approximate; a kitchen scale is the most reliable way to measure sticky pastes and sauces for a large batch.
Frequently asked questions
How much tomato sauce do I use instead of 1 tbsp of tomato paste?
Use 3 tbsp, simmered down — the ratio is 3 tbsp of tomato sauce, simmered down, per 1 tbsp of paste. One cup of tomato sauce is about 245 g and one cup of tomato paste is about 262 g, so the weights are close, but measure by volume and reduce the sauce first.
Do I have to simmer the sauce down?
Yes — that is the whole point of the swap. Tomato sauce is mostly water, and paste is concentrated, so the sauce must be reduced by about two-thirds before it can stand in for paste. Unreduced sauce will make the dish watery and weak.
How do I know when the sauce is reduced enough?
Simmer it in a wide pan until it has reduced by about two-thirds and it coats the back of a spoon. It should be thick and dark, with a deep tomato smell — if it still pours like sauce, it needs longer.
Can I use a seasoned tomato sauce?
Carefully. A sauce with herbs, garlic and salt will carry those flavours into the dish, where paste is neutral. Use a plain sauce if you can, and taste the dish before adding more seasoning.
Is this swap worth the time?
For a slow-cooked dish, yes — the reduced sauce gives a rich, deep flavour that is close to paste. For a quick dish, no: the reducing takes longer than the recipe, so use paste if you have it, or choose a different recipe.
Scaling the swap up or down
A condiment swap scales linearly in the table, but salty, sweet and sharp ingredients do not scale perfectly in the mouth — a doubled recipe often needs slightly less than double the salty or sharp ingredient, because the flavour concentrates as the dish reduces. The safe way to scale up is to add three-quarters of the scaled amount, taste, and then add the rest a little at a time. The same goes for scaling down: a single serving needs the full ratio, but a small error matters more, so measure with measuring spoons rather than by eye. When a recipe is scaled up for a crowd, make the sauce or the dressing in a separate bowl and add it to the main dish gradually, tasting as you go — it is easy to add more of a salty or sweet condiment and impossible to take it out. All amounts on this page are approximate; a kitchen scale is the most reliable way to measure sticky pastes and sauces for a large batch.
If the swap goes wrong — and how to store the substitute
If the dish comes out too sweet, add a splash of vinegar or lemon juice and a pinch of salt — acid and salt both cut sweetness without adding more liquid. If it comes out too salty, add a splash of water or an extra spoonful of the unsalted base, and let the dish simmer so the flavours meld; a pinch of sugar can also round off excess salt. If a sauce tastes flat, it usually needs acid rather than more salt — a squeeze of lemon or a dash of vinegar will lift it. Keep opened jars and bottles in the fridge, label them with the opening date, and freeze leftover tomato paste in tablespoon-sized portions so you never have to open a new tube for a single spoonful.