How long do crushed tomatoes last?
Unopened, they keep in the cupboard for about 18 months. Once opened, in the fridge for about 5 days.
This refers to: Passata / crushed tomatoes in a carton or jar.

Shelf life of crushed tomatoes at a glance
| Storage | Unopened | Opened |
|---|---|---|
| Cupboard | 18 months | – |
| Fridge | – | 5 days |
Do not keep leftovers in an open can; transfer them to a lidded container. Use within about 5 days in the fridge, or freeze.
Past its date does not mean spoiled
These are guide values for food stored correctly. A best-before date is not a throw-away date: many products are still fine after it. Check how it looks, smells and tastes. Mould, an unusual smell or a bulging can are reasons to throw it away. A use-by date is different: do not eat the food after it.