An Online ISO 6336 Gear Design Tool for Spur & Helical Gears
ISO 6336 is the international standard for the load capacity of cylindrical involute gears. Zenomiq runs the full Method B (2019) calculation in your browser — bending and pitting safety factors, with every K-factor shown — so you can rate a gear pair without installing anything.
What ISO 6336 covers
The standard is split into parts. Zenomiq implements the load-capacity core — the parts that decide whether a tooth survives.
Basic principles & influence factors
General method, application factor KA, dynamic factor Kv, and the face/transverse load distribution factors.
Surface durability (pitting)
Contact stress on the flank versus the permissible contact stress — the pitting safety factor SH.
Tooth bending strength
Root stress versus permissible bending stress — the tooth-root safety factor SF.
Material strength & quality
Endurance limits for flank and root by material and heat treatment, feeding the permissible stresses.
What the gear design tool computes
Enter geometry, material and load; get standards-traceable safety factors back in about 100 ms.
Bending safety factor (SF)
Tooth-root stress against the permissible bending stress, per ISO 6336-3, including form, stress-correction and helix factors.
Pitting safety factor (SH)
Flank contact stress against permissible contact stress, per ISO 6336-2, with zone, elasticity and contact-ratio factors.
Full K-factor breakdown
KA, Kv, KHβ / KFβ and KHα / KFα reported individually — no lumped fudge factor, so a reviewer can trace every number.
Geometry & materials
Base geometry per DIN 3960 / ISO 21771 and material endurance limits per ISO 6336-5, selectable by grade and heat treatment.
Method A, B and C — and which one to use
ISO 6336 defines several ways to derive each influence factor, ordered by rigour:
- Method A. Most accurate — derived from measurement, full elastic analysis or a comprehensive test. Rarely practical for routine design.
- Method B. The standard analytical route, and Zenomiq's default. Closed-form factors that balance accuracy and effort — what most rating reports use.
- Method C. Simplified estimates for early sizing when inputs are incomplete.
How to run an ISO 6336 rating
Define geometry & material
Teeth, module, helix angle, profile shift and centre distance — or import a CSV. Pick the material grade and heat treatment.
Set load & application factor
Enter the transmitted torque or power and speed, and the application factor KA for your duty.
Calculate & read the factors
Zenomiq returns SF and SH with the full K-factor breakdown and a report you can export.
Frequently asked questions
Which edition of ISO 6336 does the gear design tool use?+
ISO 6336:2019, using Method B for the influence factors. Material endurance data follows ISO 6336-5.
Does it handle helical gears?+
Yes — external spur and helical cylindrical gear pairs, with profile shift and tip-diameter modifications. Internal gear pairs are on the roadmap.
What safety factors does it report?+
The tooth-root bending safety factor SF (ISO 6336-3) and the surface-durability / pitting safety factor SH (ISO 6336-2), each with the underlying K-factors.
Is the calculation auditable?+
Every value maps to a clause of ISO 6336 — KA, Kv, KHβ, KHα and the permissible stresses are all shown, so there are no hidden coefficients.
Do I need to install or license anything?+
No install or license — it runs in your browser. You sign in (it takes seconds) and can use the free tier calculation modules right away; upgrade only when you need more.