The only similarity between tomato paste and tomato sauce is that they both contain tomatoes. Otherwise, these ingredients are made and used in vastly different ways.

Tomato paste is a thick substance made from highly concentrated tomatoes. It is created by simmering tomatoes for several hours and then filtering out any seeds and skin.

The best way to use tomato paste is as a thickening agent or to add a bit of tomato taste to a recipe. It works well with sauces, curries, stews, soups, and dishes like dry beans.

Unlike tomato paste, which emphasizes the tomato alone, tomato sauce contains hints of garlic, diced soft onions, and a tasty and satisfying herbaceous backdrop.

While tomato sauce is often smoother in texture than pasta sauce, tomato sauce still makes a wonderful blanket for spaghetti and is relatively easy to make.

However, tomato paste might not be a good substitute for sauce, as it lacks other flavors and doesn't unite ingredients, even when combined with water for a sauce-like consistency.