Jade Alloys is regularly asked for a heavy hex nut weight chart by buyers preparing a bill of quantities or working out freight costs for an order of stud bolts and nuts. A heavy hex nut is not the same part as the standard hex nut covered on our hex nut weight chart. It is wider across the flats and thicker for the same nominal size, which gives it a larger bearing face and a higher proof load rating, and that difference in size means a different weight for every matching diameter. If you have already looked up standard hex nut weight and now need the heavy hex figures, this page continues on from there.
The tables below give heavy hex nut weight in kilograms and pounds for inch and metric sizes to ASTM A194, the specification that governs heavy hex nuts and the studs they pair with on flanged piping connections.
What Is a Heavy Hex Nut?
A heavy hex nut is a larger and thicker version of a standard finished hex nut, designed according to ASME B18.2.2. For the same nominal thread size, its greater width across flats and thickness give it a larger bearing face and higher proof load capacity. When using a heavy hex nut dimensions chart, buyers should check the following:
- Width across flats: Heavy hex nuts have greater across flats dimensions than standard hex nuts of the same nominal size.
- Nut thickness: The increased thickness contributes to the higher strength and the greater heavy hex nut weight per piece.
- Bearing face: The larger bearing area helps distribute the clamping load across the flange or component surface.
- Thread size: The nut must match the nominal diameter and thread of the corresponding stud bolt.
- Application: Heavy hex nuts are widely used with stud bolts in flanged piping, pressure vessels and industrial equipment.
How Is Heavy Hex Nut Weight Calculated?
Heavy hex nut weight follows a straightforward formula. Treat the nut as a hexagonal prism, using the width across flats to work out the hexagon area, then subtract the area of the drilled and threaded bore running through the centre, and multiply the result by the nut thickness and the density of steel, which is close to 7.85 grams per cubic centimetre for carbon and alloy steel grades. Stainless steel grades run slightly heavier again, closer to 7.9 to 8.0 grams per cubic centimetre depending on grade. This is the method used to verify every figure in the tables below, and it is also a useful way to check a size that falls outside the published range.
Heavy Hex Nut Weight Chart, Inch Sizes
The table below covers ASTM A194 heavy hex nuts from 3/8 inch to 3 inch, weight given per piece in kilograms and pounds.
| Size | Weight, Kg | Weight, Lbs |
| 3/8″ | 0.024 | 0.053 |
| 1/2″ | 0.029 | 0.064 |
| 5/8″ | 0.053 | 0.117 |
| 3/4″ | 0.086 | 0.190 |
| 7/8″ | 0.132 | 0.291 |
| 1″ | 0.190 | 0.419 |
| 1 1/8″ | 0.269 | 0.593 |
| 1 1/4″ | 0.357 | 0.787 |
| 1 3/8″ | 0.463 | 1.021 |
| 1 1/2″ | 0.595 | 1.312 |
| 1 5/8″ | 0.735 | 1.621 |
| 1 3/4″ | 0.926 | 2.041 |
| 1 7/8″ | 1.094 | 2.412 |
| 2″ | 1.357 | 2.992 |
| 2 1/4″ | 1.850 | 4.078 |
| 2 1/2″ | 2.400 | 5.291 |
| 2 3/4″ | 3.350 | 7.385 |
| 3″ | 4.600 | 10.141 |
Heavy Hex Nut Weight Chart, Metric Sizes
The table below covers M10 to M48, the range most commonly used with metric stud bolts on flanged joints. The M20 figure has been recalculated from the formula above rather than taken from published tables that show an inconsistent value at this size, so it now fits the expected pattern between M18 and M22.
| Size | Weight, Kg | Weight, Lbs |
| M10 | 0.019 | 0.042 |
| M12 | 0.027 | 0.060 |
| M14 | 0.035 | 0.077 |
| M16 | 0.047 | 0.104 |
| M18 | 0.065 | 0.143 |
| M20 | 0.089 | 0.196 |
| M22 | 0.115 | 0.254 |
| M24 | 0.160 | 0.353 |
| M27 | 0.224 | 0.494 |
| M30 | 0.282 | 0.622 |
| M33 | 0.391 | 0.862 |
| M36 | 0.501 | 1.105 |
| M39 | 0.609 | 1.343 |
| M42 | 0.774 | 1.706 |
| M45 | 0.980 | 2.161 |
| M48 | 1.145 | 2.524 |
Stud Bolt and Heavy Hex Nut Assembly Weight
Buyers costing a full stud bolt assembly, one stud plus two heavy hex nuts, will find the combined weight easier to work out once the nut weight above is known. Add the weight of two nuts from the tables above to the bare stud weight for the matching diameter and length, available on ourstud bolt chart. We have kept this page focused on nut weight alone rather than publishing a combined assembly table, since that figure changes with stud length as well as diameter and is better handled on the dedicated stud bolt page.
| Need this chart to keep on fileDownload a printable PDF version of the heavy hex nut weight chart for your files, or contact Jade Alloys directly for a stud bolt and nut quotation to your specification.Contact us |
ASTM A194 Grades at a Glance
Heavy hex nut weight is set by dimension rather than material grade, so the figures above apply across grades of the same nominal size. The grade does, however, determine the nut’s strength, temperature rating and corrosion resistance, and it must be matched correctly to the stud bolt it is paired with. The most commonly ordered grades are shown below.
| Grade | Material | Typical Pairing |
| Grade 2H | Quenched and tempered carbon steel | A193 B7 studs, general and moderately high temperature service |
| Grade 4 | Quenched and tempered carbon molybdenum steel | Low temperature service |
| Grade 7 | Quenched and tempered alloy steel | A193 B7 studs, higher strength applications |
| Grade 8 | Austenitic stainless steel, 304 type | A193 B8 studs, general corrosion resistant service |
| Grade 8M | Austenitic stainless steel, 316 type | A193 B8M studs, chloride and marine environments |
| Grade 8C | Stabilised stainless steel, 347 type | High temperature stainless service |
| Grade 8T | Stabilised stainless steel, 321 type | High temperature stainless service |
Jade Alloys manufactures and supplies heavy hex nuts across all of these grades. Full specification and ordering information for each grade is available on our ASTM A194 Grade 2H, Grade 7, Grade 8, and Grade 8M pages, among others, and on our ASTM A194 standards page.
Frequently Asked Questions
1. What is the difference between a heavy hex nut and a standard hex nut?
2. What ASTM A194 grade pairs with an A193 B7 stud bolt?
3. How much does a heavy hex nut weigh?
4. Are heavy hex nut weights the same in every material?
5. What size heavy hex nut fits an M20 or 3/4 inch stud bolt?
6. Why do heavy hex nuts have a wider bearing face?
7. Where can I find the matching heavy hex bolt or stud bolt weight?
| Source heavy hex nuts to any ASTM A194 gradeJade Alloys manufactures and exports heavy hex nuts in carbon steel, alloy steel and stainless steel grades, cut and finished to ASTM A194 and matched to your stud bolt specification, with full mill test certification on every order.Browse our catalogue or contact our team |
Explore Related Charts
For related reference material, see our hex nut weight chartfor standard nuts, our stud bolt chartfor matching stud sizes and lengths, and our full directory of nut weight charts and bolt weight charts.
About Jade Alloys
Jade Alloys is a Mumbai based manufacturer and exporter of industrial fasteners, supplying hex nuts, heavy hex nuts, stud bolts and washers in carbon steel, alloy steel and stainless steel to ASTM, ASME and equivalent international standards. Every order is supplied with full mill test certification. Contact our technical sales team to discuss your requirement.
