How many bloods make in one day.
Answers
The process of making blood is called haematopoiesis. It is estimated that the body produces around 10mm new red blood cells per hour in the steady state, i.e. when blood is being broken down naturally and new blood is being made (you have 5 * 10 per litre of blood). Red blood cells last about 120 days and there is a daily turnover of about 0.8-1%.
Red cell production can be significantly increased if blood is being lost. The main signal known to drive this is a hormone called erythropoietin (EPO) that is produced in the kidneys.
The limiting factor seems to be the supply of iron. A normal healthy person will struggle to produce blood at 3x the baseline rate. The theoretical maximum is apparently around 4x if someone is stimulated with EPO. There's a disease called haemochromatosis where the body has too much iron and these patients can produce new blood at up to 6-8x the baseline rate.
So if we estimate that 1% of your red blood cells are being replaced each day normally, if you needed to you could probably regenerate up to 3-4% or even up to ~6-8% if you aggressively supplemented iron