# Pediatric Blood Volume Calculator

URL: https://speedycalculator.com/calculators/health/pediatric-blood-volume/
Last updated: 2026-10-30

> The pediatric blood volume calculator estimates a child's circulating blood volume from weight and age group, using the standard mL per kg values from preterm newborn to adult.

## Inputs

- Age group
- Weight (kg, lb, st, g)

## Results

- Estimated blood volume
- 10% of blood volume
- 25% of blood volume (significant loss)

## Formula

```
Blood volume = weight × mL/kg
Preterm 90–105 · term newborn 85 · infant (1–12 months) 75–80 · child 70–75 · adolescent and adult 65–70 mL/kg
```

## Explanation

Small children have small blood volumes, so what seems like a minor blood loss or a series of blood tests can be significant. A 3 kg newborn has only about 255 mL of blood.

### How to use the Pediatric Blood Volume Calculator

- **Age group**
- **Weight**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Choose the age group and enter weight.

### Inputs explained

FieldWhat to enterAge groupChoose one: Preterm newborn (100 mL/kg), Term newborn (85 mL/kg), Infant 1–12 months (78 mL/kg), Child (75 mL/kg) …WeightUnits: kg, lb, st, g

### What each result means

- **Estimated blood volume** = [Age group]×[Weight]
- **10% of blood volume** = [Estimated blood volume]×0.1
- **25% of blood volume (significant loss)** = [Estimated blood volume]×0.25

### Example values

How the main result changes when **Weight** changes and everything else stays at the example values above:

Weight (kg)Estimated blood volume (mL)10750151,125201,500251,875302,250403,000
*Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.*

## Worked example

Inputs — Age group: Child (75 mL/kg); Weight: 20 kg.

Results — **Estimated blood volume = 1,500 mL**; 10% of blood volume = 150 mL; 25% of blood volume (significant loss) = 375 mL.

## Key terms

- **EBV**: Estimated blood volume.

## FAQ

**How much blood does a newborn have?**
About 85 mL/kg – roughly 300 mL for a 3.5 kg baby.

**How much blood loss is dangerous in a child?**
Losing 25% or more of blood volume can cause shock.

**Why is the volume per kg higher in babies?**
Their bodies have proportionally more blood relative to weight.


## Sources

- [Advanced Paediatric Life Support (APLS), 7th ed.](https://www.alsg.org/)