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NLGI Grease Grade Chart

NLGI consistency grades 000 to 6 with the worked penetration range for each, measured by ASTM D217. The grade describes stiffness only, not the thickener, base oil or quality.

Ref MRO-0082ASTM D217

Draft, open for review. Check every value against the governing standard and the manufacturer’s data before use.

What it is

The NLGI grade is a number that describes how stiff a grease is. It is based on the worked penetration test in ASTM D217. A standard cone is dropped into a grease sample at 25 °C after the grease has been worked 60 double strokes. The depth the cone sinks, in tenths of a millimeter, sets the grade. Softer greases let the cone sink deeper and get a lower grade number.

How to read it

Find the NLGI grade on the product label or data sheet, often written as "NLGI 2."
A lower number is softer (000 is nearly fluid). A higher number is firmer (6 is a block).
The grade says nothing about the thickener type, base oil viscosity or additives. Check those separately on the data sheet.

Grade chart

NLGI grade	Worked penetration (0.1 mm at 25 °C)	Consistency	Typical uses
000	445–475	Semi-fluid	Enclosed gearboxes, centralized systems
00	400–430	Semi-fluid	Gearboxes, centralized systems
0	355–385	Very soft	Centralized systems, cold service
1	310–340	Soft	Cold service, pumpable applications
2	265–295	Medium	Most rolling bearings and chassis points
3	220–250	Medium-firm	Larger bearings, vertical shafts, higher speeds
4	175–205	Firm	Special applications
5	130–160	Very firm	Special applications
6	85–115	Block	Block greases for open bearings

Penetration values between the ranges fall between grades.

Key points

NLGI 2 is the most common general-purpose grade. Use the equipment maker's grade when one is given.
Softer grades pump more easily through long lines and in the cold. Firmer grades stay put better in vertical shafts and where leakage is a concern.
Grease consistency changes with temperature and with shearing in service.
The NLGI also runs a performance certification for automotive greases (GC, LB and similar marks). That is separate from the consistency grade.

Common mistakes

Reading the NLGI grade as a quality or performance rating.
Choosing grease by grade alone and ignoring base oil viscosity.
Switching grades in a centralized system without checking pumpability.

Governing standards: ASTM D217 (cone penetration of lubricating grease); NLGI consistency classification; equipment and grease maker data.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.

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