Gram-force (gf) - Unit Information & Conversion

Quick Answer

What is Gram-force? A gram-force (gf) is the force exerted by a one-gram mass in Earth's standard gravity. 1 gf = 0.00980665 newtons (approximately 9.81 millinewtons). Used for small-scale measurements like spring tension, jewelry scales, and precision instruments. Common in mechanical engineering, watchmaking, and laboratory equipment specifications. Use our force converter to convert gram-force to newtons, pound-force, and other units instantly.

Key Facts: Gram-force

Property	Value
Symbol	gf
Quantity	Force
System	Metric/SI Derived
Derived from	Newton
Category	Force
Standard Body	NIST / ISO

Quick Comparison Table

Gram-force	Newtons	Millinewtons	Context	Convert Now
1	0.00981	9.81	Small paperclip weight	gf to N →
10	0.0981	98.1	AA battery weight	gf to N →
50	0.491	491	Golf ball weight	gf to mN →
100	0.981	981	Medium apple weight	gf to N →
500	4.90	4,900	Water bottle weight	gf to N →
1,000	9.81	9,810	1 kilogram-force	gf to kgf →

Definition

Gram-force (gf) is the force exerted by one gram of mass under standard gravity (9.80665 m/s²).

Formula: 1 gf = 1 gram × 9.80665 m/s²

Conversions:

• 1 gf = 0.00980665 N (newtons)
• 1 gf = 9.80665 mN (millinewtons)
• 1 gf = 980.665 dynes
• 1 gf = 0.001 kgf (kilogram-force)
• 1 gf = 0.00220462 lbf (pounds-force)
• 1 gf = 0.035274 ozf (ounce-force)

History

Gram-force emerged from the metric gravitational system of units, which was widely used in continental Europe before the adoption of SI units. The unit is also known as "gram-weight" or "pond" (from the Latin word for weight). While it remains in common use for consumer scales, spring specifications, and small mechanical devices, scientific and engineering applications increasingly prefer SI units like millinewtons. The gram-force is particularly persistent in industries like watchmaking, jewelry, and precision instruments where tradition and existing equipment favor its continued use.

Common Uses

Laboratory Equipment: Spring scales, force gauges, material testing of small samples.

Watchmaking: Mainspring tension specifications (typically 50-500 gf).

Jewelry: Measuring clasp strength and chain durability.

Mechanical Engineering: Small spring constants, contact force specifications.

Consumer Products: Kitchen scales, postal scales, fishing line strength.

Real-World Examples

Everyday Objects:

• Paperclip weight: ~1 gf
• US penny coin: ~2.5 gf
• US nickel coin: ~5 gf
• AA battery: ~24 gf
• Large strawberry: ~20 gf
• Golf ball: ~46 gf
• Standard apple: ~100-150 gf

Mechanical Devices:

• Keyboard key actuation force: 45-80 gf
• Watch mainspring: 100-300 gf
• Pen spring: 20-50 gf
• Mechanical pencil lead: breaks at ~200-400 gf
• Eyeglass frame spring: 50-150 gf

Precision Measurements:

• Fishing line (2 lb test): ~900 gf
• Sewing thread strength: 100-500 gf
• Guitar string tension: 1,000-3,000 gf per string
• Contact lens handling force: <1 gf
• Micro-switch actuation: 10-100 gf

Real-World Examples

Precision Instrument Applications

Where gram-force remains the standard:

Industry	Application	Typical Range (gf)	Notes
Watchmaking	Mainspring tension	50-500	Critical for accuracy
Jewelry	Clasp engagement force	20-200	Must hold but be easy to open
Keyboard switches	Actuation force	45-80	Determines "feel"
Mechanical pencil	Lead ejection	100-300	Just enough to advance
Ballpoint pen	Retraction spring	20-100	User-friendly activation
Contact lenses	Handling force	<1	Extremely delicate
Eyeglass hinges	Spring tension	50-150	Must hold but allow folding

Small-Scale Material Testing

Laboratory and quality control measurements:

Test	Measurement	Typical Force (gf)	Purpose
Thread breaking	Sewing thread	100-500	Quality control
Fishing line	Tensile strength	200-3,000	2-30 lb test line
Fabric durability	Seam strength	500-2,000	Garment testing
Adhesive tape	Peel force	100-1,000	Tape quality spec
Wire spring	Compression force	50-10,000	Spring characterization

Consumer Scale Precision

Kitchen, postal, and analytical scales:

Scale Type	Measurement Range	Division	Typical Usage
Kitchen scale	0-5,000 gf	1-5 gf	Food portioning
Postal scale	0-10,000 gf	1-10 gf	Letter/package weight
Jewelry scale	0-100 gf	0.01 gf	Precious metal weighing
Laboratory balance	0-1,000 gf	0.1 gf	Chemical measurement
Analytical balance	0-100 gf	0.0001 gf	Precision research

Insight: Scales measure weight (force) by detecting gram-force applied to sensor

How do I convert gram-force to newtons?

Formula: N = gf × 0.00980665 (approximately gf ÷ 102)

Examples:

• 10 gf = 0.0981 N
• 50 gf = 0.491 N
• 100 gf = 0.981 N
• 1,000 gf = 9.81 N

Quick approximation: Divide by 102 for rough conversion.

Gram-force to Newtons converter →

How many gram-force equal one newton?

1 newton = 101.97 gram-force (approximately 102 gf)

Quick conversions:

• 0.1 N = 10.2 gf
• 1 N = 102 gf
• 10 N = 1,020 gf
• 100 N = 10,200 gf

Rule of thumb: Multiply newtons by 102 for approximate gram-force.

Newtons to Gram-force converter →

What is the difference between gram and gram-force?

Gram (g): Unit of MASS - measures amount of matter.

Gram-force (gf): Unit of FORCE - measures push or pull.

Relationship: On Earth, 1 gram of mass exerts 1 gram-force due to gravity.

Important: In physics problems, always distinguish mass from weight (force). A 1-gram object has less weight (force) on the Moon but the same mass everywhere.

When should I use gram-force instead of millinewtons?

Use gram-force when:

• Working with consumer scales or kitchen equipment
• Following specifications for springs, switches, or mechanical components
• In watchmaking, jewelry, or traditional precision crafts
• Reading older technical documentation

Use millinewtons when:

• Publishing scientific research
• Working in international engineering contexts
• Ensuring SI unit compliance
• Performing physics calculations

Note: 1 gf ≈ 9.81 mN, so the values are similar in magnitude, making conversion straightforward.

Convert gram-force to other force units →