We are a family of three also. I find that three-quarters of a 500 gram pack is enough for us. If there is a little left over, someone has it for lunch the next day.

Depends how much you eat 1/2 cup dry mays 1.5 cups I would suggest 1.5 cups dry for a meal. Everyone eats different amounts

I use half a packet for two people which is more than enough,so try 3/4 packet.

You can buy an instrument which has a hole in the plastic or wood that is a serving suggestion for spaghetti for one. You slide enough dry spaghetti into it until you can not fit any more. This measure may be in an existing measuring cup.
The pasta serve also depends on how chunky your sauce is and how much pasta ratio you want to sauce ratio.

100g for each person

Tupperware have a terrific spaghetti keeper that actually has a dispenser up the top for 1 or 2 people. No matter how many people I am feeding these days, I find it easy to choose how much to put in the pot!

I bought a plastic thing that has the measurements on it it has holes for the amount of people you want to cook for.
i think i got it from a cook shop years ago.

100g per person is a good average. If 1 person is a REALLY big eater, add an extra 50g. If 1 is a fussy toddler, deduct 50g.

I always make 100 grams per person. Less if it’s a small child. My daughter is now 12 and she eats 100 grams like us.

Italians weigh it and it’s really the only fail-safe way. Using a kitchen scale with a big bowl on top should work for just about any pasta shape. 40g for a small portion, 100g for a big plate full. Cooked volume will depend on the type of pasta, but with spaghetti for example about 55g of dry will produce about 1 cup of cooked spaghetti. and one cup of cooked spaghetti per adult person served.

2oz = about 57g and 1 cup cooked sounds like a reasonable serving size.
Serve in individual large bowls, Spaghetti in first then topped with sauce and grated cheese and garnish.

It also depends on the people being served are they big eaters? some may expect more. One way around this is to serve in large serving bowls that each person takes what they need, guests first, then you have what is left to serve yourself. You can always make more than you need as it then is saved mixed together in the fridge and can even be frozen.

Pasta generally doubles in size and weight when cooked. It is also measured differently depending upon whether it is macaroni pasta or egg noodles. Most pasta contains egg, but to be considered an egg noodle, it must contain at least 5.5 percent egg solids. When cooking pasta, you must measure the dry pasta to ensure you don’t cook too little or too much for your sauce. Some recipes merely specify the number of servings of pasta you should cook. Measuring pasta servings depends upon serving size and pasta shape.

In the kitchen gadget section of the supermarket or a kitchen shop you will often find a spaghetti measure, it’s often a long piece of plastic with holes to show how much spaghetti per person. I have been cooking pasta for a long time and I can estimate pretty accurately other pasta but not spaghetti.

We tend to find a standard packet of spaghetti serves 4 people, so perhaps just take out a small portion of the packet and set that aside – or better yet, cook the whole packet and freeze the portion you have left that way it’s not wasted.