Started counting calories, so googling calories for a food will throw up a vast diversity of results for a given food.
Is there a reliable site to use? They cannot all be correct.

Many of us use Livestrong, My Fitness Pal, or CalorieCount as they seem to have the best data and allow for free tracking. The difficulty is with homemade foods and restaurant foods. Most packaged foods are listed on at least one of the above sites. For homemade items, if you eat them often, try creating a "recipe" (at least on Livestrong, that's what it's called) where it calculates the nutritional value of everything in the recipe and in one serving. You can save it for use in the future. It's nice because you can see the effects of adding or subtracting an ingredient on the calorie count, sugar amount, etc (and the effect of changing to a smaller serving size!).

Restaurant food is tough. Some meals are listed in these tracking sites, but most aren't. And in most cases, you have only the vaguest idea of all of the ingredients used.

Also, the analysis is only as good as the data (garbage in = garbage out). So it's important to accurately measure or weigh food, in order to get the best nutritional analysis. (e.g. 1 oz of cashews is a better measurement to enter than a "handful" of cashews).

ETA: I just realized that this is the UK thread; I hope that the websites are universally useful. I know there are a bunch of weetabix listings on Livestrong so that seems like a good sign

Assuming now weetabix is a uk only food, well that's a surprise.
Thanks for the tip I'll try livestrong.

I use My Fitness Pal, I would say that it has the biggest selection of UK food. It has most of the chain foods and fast foods. The only time I think I cant scan an item for the calories is on asda or tesco's selection of british mushrooms or certain veggies. In that case I just search for generic vegetables and not where I bought them.

It is also pretty easy to use.

I used to Google a lot of foods to teach myself what the nutritional values are so when I put something into my app I can tell if what is coming up seems accurate, I can even estimate what meals out would be knowing the calories content of many food types and how they are cooked, but I only focus on a vague estimation so as I don't get too obsessed with calories.

because I have a vague idea of what most types of food should be per 100grams, like for example I went to brunch and had a big beef brioche bap with roasties, so I know the bun was 300, beef 200, sauce 100, potatoes 200, oil 100.

I use my net diary and it has worked for me for years you can also create recipes. hope it all goes well for you!