Ran out of ketchup mid-recipe? Tomato paste will do the job at 2 tbsp ketchup per 1 tbsp tomato paste (less sweet, thicker) — 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 ketchup to tomato paste for the amounts you are most likely to meet. The rule is always the same: 2 tbsp ketchup per 1 tbsp tomato paste (less sweet, thicker).
| Ketchup called for | Tomato paste to use |
|---|---|
| 1 tbsp | 2 tbsp |
| 2 tbsp | 1/4 cup |
| 3 tbsp | 6 tbsp |
| 1/4 cup | 1/2 cup |
| 1/3 cup | 2/3 cup |
| 1/2 cup | 1 cup |
By weight, one cup of ketchup is about 240 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: Barbecue glaze
A recipe for a barbecue glaze calls for 2 tbsp of ketchup. Using the ratio, that becomes 1 tbsp of tomato paste. Fry the paste in a little oil for a minute to take off its raw edge, then add a pinch of sugar and a splash of vinegar to make up what the ketchup brought. The glaze will be richer and less sweet than the original, with a deeper tomato flavour.
Example 2: Meatloaf glaze
A recipe for a meatloaf glaze calls for 1/4 cup of ketchup spread over the top. Using the ratio, that becomes 2 tbsp of tomato paste. Mix the paste with a little water, a pinch of sugar and a splash of vinegar, and spread it over the meatloaf before baking. The glaze will caramelise in the oven and give the meatloaf a rich, savoury top.
Example 3: Chilli con carne
A recipe for chilli calls for 3 tbsp of ketchup to add sweetness and body. Using the ratio, that becomes 1 1/2 tbsp of tomato paste. Fry the paste in the pot with the onions before adding the beans and tomatoes, and add a pinch of sugar if the chilli needs it. The chilli will be deeper and more savoury, with a richer tomato base.
What changes in the result
Tomato paste in place of ketchup is less sweet and much thicker, and that is the whole adjustment. Ketchup is a sweet, thin, vinegary sauce; tomato paste is concentrated cooked tomato with no added sugar, so the swap takes sweetness and thinness out of the dish and puts depth and thickness in. The ratio is two tablespoons of ketchup per tablespoon of paste, so you use half as much paste as the ketchup the recipe asks for — and you should add a pinch of sugar and a splash of water or vinegar to make up what the ketchup brought. The result is richer and more savoury, and it suits a cooked sauce far better than a cold dip.
When not to substitute
Do not make this swap where ketchup's sweetness and vinegar are the point of the dish. A dipping sauce, a burger topping, or a cocktail sauce made with ketchup will be flat and one-dimensional with tomato paste, because the paste has no sugar and no vinegar to lift it. Do not use it cold either — tomato paste needs to be cooked to lose its raw, tinny edge, and a cold paste tastes harsh. And do not use the same amount: paste is far more concentrated than ketchup, 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 2 tbsp of ketchup?
Use 1 tbsp — the ratio is 2 tbsp of ketchup per 1 tbsp of tomato paste, so you use half as much paste. One cup of ketchup is about 240 g and one cup of tomato paste is about 262 g, so the weights are close, but measure by volume for this swap.
Will the dish be less sweet?
Yes — ketchup is sweetened, and tomato paste is not. Add a pinch of sugar and a splash of vinegar to make up what the ketchup brought, and taste before serving.
Can I use tomato paste as a dip?
Not as a straight swap. Tomato paste is concentrated and needs to be cooked to lose its raw, tinny edge; a cold paste tastes harsh. Ketchup's sweetness and vinegar are what make it a dip, and paste has neither.
Do I need to cook the tomato paste?
Yes — fry it in a little oil for a minute before adding liquid. Cooking it briefly deepens the flavour and takes off the raw edge that makes uncooked paste taste tinny.
Can I use tomato paste in a burger topping?
Not as a straight swap. A burger topping needs ketchup's sweetness and vinegar, and tomato paste will taste flat and intense. Use the paste in a cooked sauce, and keep ketchup for the table.
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.