---
title: "Blaine specific surface calculator"
category: "testing-analysis-systems"
description: "Compute cement Blaine specific surface (cm²/g and m²/kg) from device constant K, density, air-flow time, and optional porosity and temperature — aligned with EN 196-6 and ASTM C204 practice."
relatedStandards: ["EN 196-6","ASTM C204","BS 4550","AASHTO T153"]
url: "https://vectorbtc.com.tr/resources/calculators/blaine-fineness/"
---

## What this measures

**Specific surface area (S)** is the total surface of all particles in one gram of material. Blaine air permeability relates measured **air-flow time** *t* through a compacted powder bed to *S*, using the bed porosity **e**, cement density **ρ**, air viscosity **η**, and an apparatus **device constant K** found by calibration on reference cement.

| Unit | Meaning |
|------|---------|
| **cm²/g** | Common on Blaine reports (e.g. 48 800) |
| **m²/kg** | SI-friendly; **1 cm²/g = 0.1 m²/kg** |

Finer grinding increases surface area, lengthens flow time, and increases *S*.

## General formula

```text
S = (K/ρ) · (√e³ / (1−e)) · (√t / √(0.1·η))
```

- **S** — cm²/g; **ρ** — g/cm³; **e** — bed porosity (0–1); **t** — s; **η** — Pa·s from air temperature (Sutherland).
- **K** — dimensionless constant for your cell, preparation, and procedure (reference cement calibration).

## Simplified shortcut

At **e = 0.500** and **~20 °C** (fixed η):

```text
S = (524.2 · K / ρ) · √t
```

Use the **General** mode when porosity or lab temperature differ from standard practice.

## Device constant K

**K** is not a universal physical constant. Invert the formula with a certified reference cement (*S*<sub>ref</sub>, measured *t*<sub>ref</sub>, same *ρ*, *e*, temperature) — see **Advanced options** on the calculator.

## Bed volume and specimen mass

Before measuring *t*, prepare a bed at target **e**:

- **V** = (*m*₂ − *m*₃) / ρ<sub>H</sub> (cm³) from mercury masses, or enter **V** manually if already known.
- **m** = (1 − *e*) · ρ · **V** (g) — at *e* = 0.5, half the bed volume is solid cement.

## Common errors

| Issue | Effect |
|-------|--------|
| Assuming *e* = 0.5 while the bed is off-spec | Systematic bias in *S* |
| Ignoring temperature with the simplified formula | Slight *S* drift |
| Wrong **ρ** or stale **K** | Scaled or shifted results |
| Poor compaction or cracked bed | Scattered *t*, repeat test |

## Disclaimer

This tool supports training and cross-checks. **EN 196-6**, **ASTM C204**, and your accredited quality system define binding requirements for apparatus, bed preparation, and reporting.