Sugar: the facts - FROM NHS UK

How much sugar can we eat?
The government recommends that free sugars – sugars added to food or drinks, and sugars found naturally in honey, syrups, and unsweetened fruit and vegetable juices, smoothies and purées – should not make up more than 5% of the energy (calories) you get from food and drink each day.

This means:

Adults should have no more than 30g of free sugars a day, (roughly equivalent to 7 sugar cubes).
Children aged 7 to 10 should have no more than 24g of free sugars a day (6 sugar cubes).
Children aged 4 to 6 should have no more than 19g of free sugars a day (5 sugar cubes).
There's no guideline limit for children under the age of 4, but it's recommended they avoid sugar-sweetened drinks and food with sugar added to it.