Ran out of tomato paste mid-recipe? Tomato sauce will do the job at 1 tbsp paste + 2 tbsp water per 3 tbsp sauce — 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 paste to tomato sauce for the amounts you are most likely to meet. The rule is always the same: 1 tbsp paste + 2 tbsp water per 3 tbsp sauce.
| Tomato paste called for | Tomato sauce to use |
|---|---|
| 3 tbsp | 1 tbsp paste + 2 tbsp water |
| 6 tbsp | 2 tbsp paste + 4 tbsp water |
| 9 tbsp | 3 tbsp paste + 6 tbsp water |
| 1/2 cup | 2 tbsp + 2 tsp paste + 5 tbsp + 1 tsp water |
| 3/4 cup | 1/4 cup paste + 1/2 cup water |
| 1 cup | 1/3 cup paste + 2/3 cup water |
By weight, one cup of tomato paste is about 262 g (spooned and levelled, USDA) and one cup of tomato sauce is about 245 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: Pasta sauce
A recipe for a pasta sauce calls for 1/2 cup of tomato sauce. Using the ratio, that becomes 2 tbsp plus 2 tsp of tomato paste whisked into 5 tbsp plus 1 tsp of water. Whisk the paste into the water until it is smooth, then add it to the pan with the garlic and herbs and simmer briefly. The sauce will be rich and savoury, a little more intense than a fresh tomato sauce.
Example 2: Tomato soup
A recipe for tomato soup calls for 1 cup of tomato sauce. Using the ratio, that becomes 1/3 cup of tomato paste whisked into 2/3 cup of water. Whisk the paste into the water until it is smooth, add it to the pot with the stock, and simmer. The soup will be rich and deep, though it will taste more cooked than a soup made with fresh sauce.
Example 3: Braised chicken
A recipe for braised chicken calls for 3/4 cup of tomato sauce. Using the ratio, that becomes 1/4 cup of tomato paste whisked into 1/2 cup of water. Add the diluted paste to the pot with the chicken and the braising liquid, and let it simmer. The braise will be rich and savoury.
What changes in the result
Tomato sauce in place of tomato paste is thinner and less concentrated, and the swap is a simple dilution: one tablespoon of paste plus two tablespoons of water makes three tablespoons of sauce. The ratio is one tablespoon of paste plus two tablespoons of water per three tablespoons of sauce. The result is close to a plain tomato sauce in body and flavour, though a little richer, because paste is more intensely flavoured than a sauce made from fresh tomatoes. The swap works well in a pasta sauce, a soup or a braise, where the sauce is one ingredient among many — and it is a poor swap where the recipe needs a thin, fresh sauce, because the paste version will taste cooked and concentrated.
When not to substitute
Do not make this swap where the recipe needs a thin, fresh tomato sauce. A raw sauce, a light pasta sauce, or a dish where the tomato should taste fresh and bright will be wrong with a paste-based sauce: the flavour is cooked and concentrated, and it will dominate. Do not use it in a dish that must be ready quickly either — the paste needs to be whisked into the water and simmered briefly, or it will stay in lumps. And do not use the same amount of paste as the sauce: paste is far more concentrated, so using a one-to-one amount will make the dish too intense and too thick.
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 paste do I use instead of 3 tbsp of tomato sauce?
Use 1 tbsp of paste plus 2 tbsp of water — the ratio is 1 tbsp of paste plus 2 tbsp of water per 3 tbsp of sauce. One cup of tomato paste is about 262 g and one cup of tomato sauce is about 245 g, so the weights are close, but measure by volume for this swap.
Will the sauce taste different?
A little. Paste is more intensely flavoured than a sauce made from fresh tomatoes, so the diluted version will taste richer and more cooked. That suits a pasta sauce or a braise, and it will dominate a light, fresh sauce.
Do I need to whisk the paste into the water?
Yes — whisk it until it is smooth before adding it to the pan. Paste added straight to a hot pan will stay in lumps and will not distribute evenly through the sauce.
Can I use this for a raw tomato sauce?
No — a raw sauce needs fresh tomatoes, and a paste-based sauce will taste cooked and concentrated. Use this swap for cooked sauces, soups and braises, not for a raw sauce.
Can I make a whole cup of sauce this way?
Yes — whisk 1/3 cup of tomato paste into 2/3 cup of water. It will be a rich, savoury sauce, though it will taste more cooked than a sauce made from fresh tomatoes.
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 a tomato sauce tastes tinny or raw, the paste or purée was not cooked long enough — fry it in a little oil for a minute before adding liquid, and the flavour will deepen. If a dressing separates, the mustard or the paste was not whisked in properly: whisk the thick ingredient into the vinegar first, then add the oil in a slow stream while whisking. If a marinade is too sharp, add a pinch of sugar and let the meat marinate for less time next time. Store opened condiments in the fridge and check them before use — a sauce that smells off or has mould on the surface should be thrown away, not scraped clean.