Weight-based dosing of fresh frozen plasma (FFP) is used to replace multiple coagulation factors in bleeding patients or those at high risk of bleeding when specific factor concentrates are unavailable or unsuitable.

In adults, most guidance aims to raise coagulation factor activity to roughly 30% of normal. This is usually achieved with about 10–15 mL/kg of FFP, with Australian Red Cross Lifeblood and National Blood Authority patient blood management materials describing a standard adult dose of 10–15 mL/kg (typically 3–4 units for a 70 kg adult, depending on bag volume). International reviews and perioperative guidelines often quote a broader 10–20 mL/kg range, with higher doses up to around 30 mL/kg in selected cases of severe coagulopathy, guided by repeated coagulation testing.

Source	Population / setting	Suggested FFP dose	Typical adult units
Australian Red Cross Lifeblood / National Blood Authority	Adults, perioperative and general use	10–15 mL/kg. 15 mL/kg commonly used	~3–4 units for a 70 kg adult (bags ~250–330 mL)
International perioperative and massive bleeding guidance	Adults with significant bleeding or coagulopathy	Typical therapeutic dose 15–20 mL/kg. Higher doses up to ~30 mL/kg in selected coagulopathies	Adjusted to clinical context and coagulation results
StatPearls and other reviews	Adults with bleeding or high-risk procedures	10–20 mL/kg, often ~12–15 mL/kg in many adults	Often 4–6 units, depending on bag size
NHSBT FFP dosage audit poster	UK adults	Therapeutic dose 12–15 mL/kg. Doses <10 mL/kg often subtherapeutic	~3–4 units

Audits show that empiric orders for one or two units of plasma frequently deliver <10 mL/kg, which may be inadequate to correct significant coagulopathy. Conversely, large cumulative FFP volumes increase the risk of transfusion-associated circulatory overload and transfusion-related acute lung injury, particularly in older patients and those with cardiac or renal impairment.

This calculator encodes the weight × dose formula and converts the total FFP volume into an approximate unit count using the entered bag volume. It is aligned with adult practice. Neonatal and paediatric use, liver failure, thrombotic thrombocytopenic purpura, and other complex scenarios should follow specialist protocols and local transfusion guidance.

Fresh frozen plasma (FFP) dosage