Have you thought of donating blood but haven’t gotten around to it? Here what you need to know! The entire process takes approximately one hour, but only 10 of those minutes are actually spent donating blood. The average human has anywhere from 5 – 6 litres of blood in their body. One unit of blood is 450ml or about a 1/12 of your total blood volume. You body regenerates this volume within hours. Lastly, your unit will be used to help save a patient’s life within five days of its donation. Now that’s something worth trying!