Metal Sheet Gauge Calculator
A Number That Gets Smaller as the Metal Gets Thicker
Sheet metal gauge is one of the more counterintuitive numbering systems still in everyday use — a higher gauge number means thinner material, the reverse of what most people expect from a size number. This calculator converts between Manufacturers' Standard Gauge (MSG) numbers and actual thickness for steel sheet in both directions.
Reference Table
A selection of the Manufacturers' Standard Gauge table for uncoated steel sheet, used directly by the calculator:
| Gauge | Thickness (in) | Thickness (mm) |
|---|---|---|
| 7 | 0.1793 | 4.554 |
| 10 | 0.1345 | 3.416 |
| 14 | 0.0747 | 1.897 |
| 16 | 0.0598 | 1.519 |
| 18 | 0.0478 | 1.214 |
| 20 | 0.0359 | 0.912 |
| 24 | 0.0239 | 0.607 |
| 26 | 0.0179 | 0.455 |
This is the standard steel MSG table specifically — aluminum and brass sheet use different gauge-to-thickness conventions, so a gauge number alone is meaningless without knowing which system it refers to.
Where This Calculation Matters
- Reading a supplier spec sheet — converting a gauge callout on a material order into an actual thickness for design or tolerancing purposes.
- Cross-checking incoming material — verifying a delivered sheet's measured thickness corresponds to the gauge it was ordered as.
- Drawing and specification consistency — converting between gauge numbers and decimal thickness when a design uses one convention and a shop drawing uses another.
How to Use This Calculator
- Choose the mode: Gauge to Thickness or Thickness to Gauge.
- For gauge to thickness, enter a Gauge Number (3-30).
- For thickness to gauge, enter a Thickness (inches) and the calculator finds the closest standard gauge.
- Select Calculate to get the result.
Related Calculations
Once thickness is confirmed, calculate the sheet's total weight with the Sheet Metal Weight Calculator.