Length · Unit Converter

Convert Square Chain to Square Thou

Convert square chains to square thous instantly. 1 square chain = 6.27264e+11 square thou — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Square Thou to Square Chain converter for the reverse conversion.

Written by Sunith Babu L, Ph.D., Lead Engineer Reviewed by Girish V Kulkarni Ph.D.
Length category 2 min read Published Last reviewed Updated

Units explained

Imperial / US Customary

Square Chain

What is a square chain?

A square chain is an imperial unit of area equal to approximately 404.686 m². It equals 1/10 of an acre.

Origin of the square chain

Derived by squaring the chain (66 feet or 22 yards). The chain was defined by Edmund Gunter in 1620 specifically so that 10 square chains equal exactly one acre.

Where it is used

Square chains appear in US Public Land Survey System (PLSS) records and historical English property documents. The 10-to-1 ratio with acres made early survey arithmetic easier.

When and where it was developed

Defined by Edmund Gunter in 1620 specifically for surveying convenience.

Imperial / US Customary

Square Thou

What is a square thou?

A square thou is an imperial unit of area equal to 6.4516×10⁻¹⁰ m², identical to the square mil. The word 'thou' is short for 'thousandth' (of an inch).

Origin of the square thou

Identical in value to the square mil; 'thou' is the British engineering term, 'mil' is the American term. Both refer to 1/1000 of an inch.

Where it is used

Square thous are used in British and Commonwealth engineering contexts where 'thou' is preferred over 'mil', particularly in mechanical engineering tolerance specifications.

When and where it was developed

Standardized via the 1959 International Yard and Pound Agreement.

Square Chain to Square Thou conversion formula

The relationship between square chains and square thous:

1 ch² = 6.27264e+11 thou²
1 thou² = 1.594225e-12 ch²

To convert square chains to square thous, multiply the value in square chains by 6.27264e+11. To reverse, multiply square thous by 1.594225e-12.

How to use this converter

Type a value into the calculator. The result in square thous updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Square Thou to Square Chain converter for the reverse direction.

Step-by-step: convert square chains to square thous

  1. Write down the value in square chains (ch²).
  2. Multiply that value by the factor 6.27264e+11.
  3. The product is the equivalent value in square thous (thou²).
  4. To reverse, multiply the square thou value by 1.594225e-12.

Worked examples

Example 1 — Convert 1 ch² to thou²:
1 × 6.27264e+11 = 6.27264e+11 thou²

Example 2 — Convert 100 ch² to thou²:
100 × 6.27264e+11 = 6.27264e+13 thou²

Square Chain to Square Thou conversion table

Standard reference values for converting square chains to square thous:

Square Chain [ch²]Square Thou [thou²]
0.016.27264e+9
0.16.27264e+10
16.27264e+11
21.254528e+12
31.881792e+12
42.509056e+12
53.13632e+12
106.27264e+12
201.254528e+13
301.881792e+13
402.509056e+13
503.13632e+13
1006.27264e+13
5003.13632e+14
10006.27264e+14

Frequently asked questions

How many square thous is 1 square chain?
1 square chain equals 6.27264e+11 square thou.
How do I convert square chains to square thous?
Multiply the value in square chains by 6.27264e+11 to get square thous.
How do I convert square thous back to square chains?
Multiply the value in square thous by 1.594225e-12, or use the Square Thou to Square Chain converter.
How many square thous is 100 square chains?
100 square chains equals 6.27264e+13 square thous, because 100 × 6.27264e+11 = 6.27264e+13.

Convert Square Chain to other area units

Show all Square Chain conversions

Sources & references

Conversion factor (1 ch² = 6.27264e+11 thou²) verified against the following authoritative sources:

Results are provided for general reference. Verify critical measurements against an authoritative standard.