Print Free Graph Paper is a great site for printing graph paper for your Maths and Science projects.
The most useful settings for us are:
1. Cartesian Graph Paper (this is the normal graph paper)
2. A4 - 210mm x 297mm
4. 5mm Cartesian Graph Paper
This generates a PDF document that you can print, or better still, save the file and then you can print from it at any time.