Bolt weight calculator

A good tool is only half of the answer — the other half is knowing what the result means. The tool is free, instant and private; the text below makes sure the result doesn't get misread.

Accuracy has a quiet enemy: sloppy inputs. They are drawn from situations people actually run into, so you can map your own case onto them.

What sits behind the number

For critical joints use a torque wrench with ±4% accuracy. On technical fasteners errors are paid at once: too little torque means a loose joint; too much means stripped threads or a cracked head. Bolt weight Canadian calculation tool turns bolt, screw and nut specs into concrete numbers — torque, shear load, preload, weight.

Respect the torque, pick the right class, log the batch — that's the difference between a joint that holds for 20 years and one that fails on first vibration. The values entered here are Nominal diameter (mm), Shank length (mm), Material.

Start by checking the input fields rather than the final number.

How the result is computed

Use before assembling a critical structure, when writing an engineering spec, when checking a torque-wrench installation, when computing weight for shipping, or when picking the right property class for the application. Bolt weight Canadian calculation tool turns standards into applied numbers so you don't rely on 'experience'.

Example: a M10 class 8.8 bolt at friction coefficient 0.15 requires a specific torque in Nm. DIN 933 (ISO 4017) — fully threaded. For M10 8.8 that's about 47 Nm dry, ~35 Nm lubricated. Lubrication cuts required torque 20–30% because less friction means the same torque delivers higher preload.

Typical moments to reach for it

• Local notes: Amounts on this page use Canadian dollars and metric units, with provincial variation noted where it matters.
• Currency & format: Canadian dollar (CAD, $ or C$). Quebec uses comma as decimal (1 000,00 $), rest of Canada uses period.
• VAT / sales tax: Canada layers federal GST (5%) with provincial sales tax: HST (13–15%) in ON, NB, NL, NS, PE; separate PST/QST in BC, SK, MB, QC (5–9.975%). Alberta and territories charge only the 5% GST.
• Units of assess: Officially metric (km, kg, °C, L) but Imperial holdovers persist: heights in feet/inches, weights in pounds, oven temperatures regularly °F. Grocery pricing typically per 100 g.
• Electrical supply: 120 V / 60 Hz, Type A/B plugs (same as US).

Getting your result

Most common: using one torque amount for dry and lubricated joints (25% error). Never grow torque to compensate for loosening — replace the fastener. Third: over-tightening stainless — A2/A4 have 60–70% the strength of class 8.8 steel. For repeatedly disassembled joints — use self-locking nuts or spring washers.

Re-check torque after 24 hours (preload drops 5–10% on first loading). Second: ignoring property class — 4.6 and 12.9 need very different torque at the same diameter.

Who benefits most

Down-substitution risks shear failure or loosening. 10.9 is 25% stronger tensile and used in preloaded joints (structural steel, engines). DIN 931 (ISO 4014) — partial thread (plain shank under the head).

Only with designer approval. Use 931 for shear joints, 933 for tension.

Mistakes worth dodging

Every figure above applies to Canada specifically and is reviewed when the rules change. Typical visitors are users in Toronto, Vancouver, Montreal and Calgary comparing offers or checking a bill, so the worked examples below use achievable local values rather than abstract numbers. Steel: 4.6, 5.6, 8.8, 10.9, 12.9. Canada mixes metric measurement with imperial habits, so Bolt weight calculator is establish to match what people actually quote here.

Notes from experience

Check the head markings. Recalculate after changing one input at a time; this presents which assumption controls the calculated number and makes an unexpected answer easier to diagnose.

Keep the original measurement, invoice, specification or log beside the calculation so that a misplaced decimal point can be found. Stainless: A2-70, A4-70, A4-80.

The short version

The difference between a good and a bad move is regularly a single computed figure. Keep your inputs honest and the bolt weight calculator will keep its outcomes honest.