Is there any web site that shows average Ph.D. student salaries in European countries, and also information about living cost and so on?
update: what about France and Germany?
Partial answer; In the Netherlands you have a couple of different possibilities when it comes to PhDs. You can be a student (and thus have to pay), a payed phd (who also has teaching obligations), and an external PhD (who, depending on the professor, might have to pay).
The paid PhDs salary per month vary from 2,125 euro in the first year to 2,717 euro (in the fourth year, which should be the last year) according to the VSNU (look at the P column). There is also a 13th month and vacation money. Of course tax and social premiums still has to be deducted to get to the salary you get on your account.
In Germany, PhD work contracts are typically under the TVL group "E 13" union contracts. Fresh PhD students start in stage 1, but if you have relevant work experience, starting in stage 2 or 3 is possible as well.
Usually, PhD contracts are part time, either 50 % or 65 %. In some occasions the PhD students are not paid for the PhD work, but explicitly for the teaching they do ("PhD is your private fun"), occasionally also only by HiWi contracts (much less hourly wage). A 50 % contract in E13 stage 1 yields approximately 1175 €/month net after taxes and social insurance (health insurances, unemployment insurance, pension fund contribution) have been paid. For more details, the linked page has a calculator that takes into acount further details.
If you are not paid by a work contract but by a scholarship, things are very different: firstly, scholarships can vary widely by the amount they pay and the additional conditions. Secondy, scholarships are not work contracts. Which means that you have to pay e.g. full health insurance yourself, and no pension payments are done. On the other hand, there is no income tax on scholarships, nor do they count for the tax progression (=> if you earn additional money e.g. for teaching, that will practically have no/very low income tax as well because of the income tax free limit).
As for how far that money gets you, this varies hugely between regions. E.g. Munich or Frankfurt are very expensive as housing costs are very expensive (shared flat > 25 €/m²), wheras other cities such as Leipzig are much cheaper to live in (maybe 10 €/m² for shared flat), have a look e.g. at WG-gesucht to get an idea of housing costs. Basic food stuff (= buying ingredients and cooking yourself) is cheap in Germany.
It is typically up to you whether you want to sign up as a university student when doing a PhD. People often decide this by comparing the semester fees with the advantages that come with the student ID such as public transport ticket or the lower mensa prices.
New partial answer : in Sweden it is pretty much like for the Nederland. The rules are the same but you're paid around 24 000 krona (around 2400€) a month. You then have to deduct the tax which depend on where you live. No extra taxes but I'm from the EU and it might be different if you're from outside the eu. The salary is based on the cost of living.
You have teaching obligation and are supposed to spend 20% of your time on work for the university (as in not on research).
You sign a contact with the university. So you're employed and you have all the advantages of a normal employee: health insurance and 25 days of holidays, for example. Security insurance might be only on campus.
For the savings, it depend on where you live and the way you live but you definitely can save some ;).
Another partial answer. In Italy there are two categories of PhD students: those who get a scholarship from the university or a government institution, and those who are funded by an industry or a firm (not many, actually).
For the first category, the scholarships are of about €1000-1200 per month, free of tax, and the students do not have to pay any yearly fee for the enrollment. For the second category, the salary depends on the funder, but it is probably of the same order of magnitude. In this latter case, however, students have to pay a yearly fee (around €1000-2000) to the school.
PhD students can have extra income from teaching assistantship or external contracts. The law does not limit the amount of extra income, but schools can set local limits. In any case, extra activity which involves a student for a significant amount of hours should be approved by the PhD program board and by the student's advisor(s).
This is what I found with a simple Google search: The average PhD Student salary is US$28,928. This comes to about €26,322. The estimates are based on 1,086 salaries submitted anonymously to the Glassdoor website by PhD Student employees. Needless to say it will vary based on the area of research, location and University/Institution. It closely matches to my PhD salary though. I looked up the list and it featured entries from US, UK and Nordic countries.
In the UK PhD salaries vary a bit by location but they are around 1000£ per month. It counts as a bursary and is thus tax exempt. The living costs vary drastically depending on where you live but generally it is enough to get by and maybe even safe some money. The rule of thumb is the further south you live the more expensive. Keep in mind that as taxes are quite high in the UK there are plenty of people working full time jobs that in the end will have less than that to live up on.
Switzerland, has a slightly wired system. The PhD salaries vary by field, fields in which it is hard to find anyone interested in pursuing an academic career will be paid much better then others. Most of my friends are paid around 3600Fr per month. Which would be seen as a low income in Switzerland but it is perfectly fine to live up on. One of my fiends has 2400Fr, you can just about live on that if you must but it will be tough. All incomes are taxed in Switzerland, no matter how low but taxes on low incomes are not high.