The ratio for the perfect balance of coffee and water is called the Golden Ratio and was developed by the SCAA (Specialty Coffee Association of America) to ensure the best cup of coffee.
This ratio is 10 grams of coffee for 180ml of water (180g of water). This process requires a coffee scale (these are affordable and can be purchased online).
If we want to simplify it a little bit, or you don’t want to buy a scale, an easy recipe for most home brewing is 2 tbsp (10.6g) of ground coffee for every 60 oz of water.