Ounce-force (ozf) - Unit Information & Conversion

Quick Answer

What is Ounce-force? An ounce-force (ozf) is the force exerted by a one-ounce mass in Earth's standard gravity. 1 ozf = 0.278014 newtons = 1/16 pound-force. Used for small force measurements in US applications like spring scales, fishing equipment, food packaging, and precision mechanical devices. Common in consumer products and older engineering specifications. Use our force converter to convert ounce-force to newtons, pounds-force, and other units instantly.

Quick Comparison Table

Definition

Ounce-force (ozf) is the force exerted by one avoirdupois ounce of mass under standard gravity (32.174 ft/s²).

Formula: 1 ozf = 1 oz × 32.174 ft/s²

Conversions:

• 1 ozf = 0.278014 N (newtons)
• 1 ozf = 0.0625 lbf (1/16 pound-force)
• 1 ozf = 28.35 gf (gram-force)
• 1 ozf = 0.02835 kgf (kilogram-force)
• 1 ozf = 278,014 dynes
• 16 ozf = 1 lbf

History

Ounce-force derives from the avoirdupois ounce, part of the imperial system developed in medieval England for commerce. The ounce (1/16 of a pound) was standardized for general goods, distinguishing it from the troy ounce used for precious metals. As a force unit, ounce-force became common in applications requiring finer precision than pounds, such as pharmacy scales, postal scales, and small mechanical springs. While metric units have largely replaced ozf in scientific and international contexts, it persists in US consumer products, food packaging, fishing equipment, and some mechanical specifications.

Common Uses

Consumer Products: Package weight labels, kitchen scales, postal scales.

Fishing Equipment: Fishing line test strength, lure weights, rod action ratings.

Food Industry: Portion control, ingredient measurements, packaging specifications.

Small Springs: Tension spring ratings, retractable mechanisms, small mechanical devices.

Precision Scales: Laboratory balances, jewelry scales, pharmacy measurements.

Real-World Examples

Food and Kitchen:

• Slice of bread: ~1 ozf
• Large egg: ~2 ozf
• Stick of butter: ~4 ozf
• Average apple: ~5-7 ozf
• Can of soda: ~12-13 ozf
• Box of pasta: ~16 ozf (1 lb)

Fishing Equipment:

• Light fishing line: 2-8 ozf test
• Trout fishing leader: 4-12 ozf
• Small fishing lure: 0.5-2 ozf
• Bobber weight: 0.25-1 ozf
• Ice fishing line: 1-4 ozf test
• Ultralight rod rating: 1-8 ozf

Small Mechanical Devices:

• Retractable pen spring: 2-6 ozf
• Cabinet door closer: 4-16 ozf
• Tape measure return spring: 8-24 ozf
• Window shade spring: 16-64 ozf
• Small extension spring: 1-20 ozf
• Badge reel: 2-8 ozf retraction force

Everyday Objects:

• US quarter coin: ~0.2 ozf
• AA battery: ~0.8 ozf
• Standard pencil: ~0.3 ozf
• Playing card: ~0.06 ozf
• Business card: ~0.06 ozf
• Empty aluminum can: ~0.5 ozf