Convert Ounces to Milligrams
Instantly convert Ounces (oz) to Milligrams (mg) with our free online calculator.
Formula: oz to mg — multiply by 28349.5
Reference Table
| Ounces (oz) | Milligrams (mg) |
|---|---|
| 1 | 28349.5 |
| 5 | 141748 |
| 10 | 283495 |
| 25 | 708738 |
| 50 | 1417480 |
| 100 | 2834950 |
How to Convert Ounces to Milligrams
Formula
To convert Ounces (oz) to Milligrams (mg): multiply by 28349.5
Step-by-Step
- Start with your value in Ounces (oz).
- Multiply by 28349.5 to perform the conversion.
- The result is your value expressed in Milligrams (mg).
Conversion Factor
1 oz = 28349.5 mg
Reverse Factor
1 mg = 0.000035274 oz
Worked Example
Convert 25 Ounces to Milligrams: 25 oz = 708738 mg
About Ounce (oz)
An imperial unit of mass equal to exactly 1/16 of an avoirdupois pound = 28.349523125 g per NIST SP 811. The avoirdupois ounce is the everyday US small-mass unit for: food portion sizes per FDA 21 CFR 101.9 + USDA Food Patterns (typical protein serving 3 oz cooked meat; 1 oz cheese; 1 oz nuts; 8 oz cup of liquid; lean meat lean 3-4 oz recommended per meal), American cookbook ingredient measurements (1 tablespoon = 0.5 fl oz volume but the 'oz' in 'oz of flour' is mass = 28.35 g), boxing glove weights per Boxing Association rules (typical 8-10 oz pro-boxing; 12-16 oz training-bag), postal rates per USPS (Domestic First-Class up to 13 oz, then Priority Mail rates; international First-Class up to 4 lb in oz increments), and chocolate-bar + nut + cereal-product labeling. Reference values: 1 stick of US butter = 4 oz = 1/2 cup = 8 tablespoons; an Apple iPhone 15 Pro Max ~7.8 oz; a US baseball regulation 5-5¼ oz per MLB rule 3.01. CRITICAL: distinct from troy ounce (~31.103 g, used exclusively for precious metals — 1 troy oz Au differs from 1 avoirdupois oz Au by ~10%, a common confusion when comparing gold quotes to grocery scales). Convert avoirdupois oz to grams by multiplying by 28.349; to troy oz by dividing by 1.097.
About Milligram (mg)
A metric unit of mass equal to exactly 0.001 g = 10⁻⁶ kg = 10⁻³ g. The milligram is the standard unit for pharmaceutical dosing per FDA + EMA + ICH guidelines + USP <795> (typical tablet contents 50-1000 mg active pharmaceutical ingredient; aspirin 81 mg or 325 mg; ibuprofen 200/400/600 mg; acetaminophen 325/500 mg; amoxicillin 250/500 mg; metformin 500/850/1000 mg; ranitidine 75/150 mg; warfarin 1/2.5/5 mg), vitamin and supplement labeling per FDA 21 CFR 101.36 + 21 CFR 101.9 + EFSA NRV (vitamin C 60-1000 mg/day; calcium 1000-1200 mg/day; iron 8-18 mg/day; magnesium 310-420 mg/day; zinc 8-11 mg/day), trace analytical chemistry, nutritional micronutrient values (sodium content quoted in mg per serving; daily limit 2,300 mg per FDA 2020 Dietary Guidelines; caffeine in coffee ~95 mg per 8 oz cup), environmental pollutant concentrations (drinking-water mg/L = ppm; EPA MCLs in mg/L for lead 0.015, arsenic 0.010, copper 1.3), and air-quality regulations per EPA NAAQS (CO 9 ppm 8-hr = 10 mg/m³). Convert mg to grains by multiplying by 0.01543; to grams by multiplying by 0.001.
Quick Facts
- 1 Ounce equals 28349.5 Milligrams
- 1 Milligram equals 0.000035274 Ounces
- Ounce is a unit of weight & mass
- Milligram is a unit of weight & mass
- This conversion is commonly used in cooking, shipping, fitness, and scientific research
- The Ounce belongs to the imperial system
- The Milligram belongs to the metric system
Common Ounce to Milligram Conversions
| Ounces (oz) | Milligrams (mg) |
|---|---|
| 0.01 | 283.495 |
| 0.1 | 2834.95 |
| 0.25 | 7087.38 |
| 0.5 | 14174.8 |
| 1 | 28349.5 |
| 2 | 56699 |
| 3 | 85048.6 |
| 5 | 141748 |
| 10 | 283495 |
| 15 | 425243 |
| 20 | 566990 |
| 25 | 708738 |
| 50 | 1417480 |
| 75 | 2126210 |
| 100 | 2834950 |
| 250 | 7087380 |
| 500 | 14174800 |
| 1000 | 28349500 |
| 5000 | 141748000 |
| 10000 | 283495000 |
Understanding Ounces
The Ounce (symbol: oz) is a unit of weight & mass. An imperial unit of mass equal to exactly 1/16 of an avoirdupois pound = 28.349523125 g per NIST SP 811. The avoirdupois ounce is the everyday US small-mass unit for: food portion sizes per FDA 21 CFR 101.9 + USDA Food Patterns (typical protein serving 3 oz cooked meat; 1 oz cheese; 1 oz nuts; 8 oz cup of liquid; lean meat lean 3-4 oz recommended per meal), American cookbook ingredient measurements (1 tablespoon = 0.5 fl oz volume but the 'oz' in 'oz of flour' is mass = 28.35 g), boxing glove weights per Boxing Association rules (typical 8-10 oz pro-boxing; 12-16 oz training-bag), postal rates per USPS (Domestic First-Class up to 13 oz, then Priority Mail rates; international First-Class up to 4 lb in oz increments), and chocolate-bar + nut + cereal-product labeling. Reference values: 1 stick of US butter = 4 oz = 1/2 cup = 8 tablespoons; an Apple iPhone 15 Pro Max ~7.8 oz; a US baseball regulation 5-5¼ oz per MLB rule 3.01. CRITICAL: distinct from troy ounce (~31.103 g, used exclusively for precious metals — 1 troy oz Au differs from 1 avoirdupois oz Au by ~10%, a common confusion when comparing gold quotes to grocery scales). Convert avoirdupois oz to grams by multiplying by 28.349; to troy oz by dividing by 1.097.
It belongs to the imperial measurement system.
Ounces are commonly used in cooking, shipping, fitness, and scientific research.
Understanding Milligrams
The Milligram (symbol: mg) is a unit of weight & mass. A metric unit of mass equal to exactly 0.001 g = 10⁻⁶ kg = 10⁻³ g. The milligram is the standard unit for pharmaceutical dosing per FDA + EMA + ICH guidelines + USP <795> (typical tablet contents 50-1000 mg active pharmaceutical ingredient; aspirin 81 mg or 325 mg; ibuprofen 200/400/600 mg; acetaminophen 325/500 mg; amoxicillin 250/500 mg; metformin 500/850/1000 mg; ranitidine 75/150 mg; warfarin 1/2.5/5 mg), vitamin and supplement labeling per FDA 21 CFR 101.36 + 21 CFR 101.9 + EFSA NRV (vitamin C 60-1000 mg/day; calcium 1000-1200 mg/day; iron 8-18 mg/day; magnesium 310-420 mg/day; zinc 8-11 mg/day), trace analytical chemistry, nutritional micronutrient values (sodium content quoted in mg per serving; daily limit 2,300 mg per FDA 2020 Dietary Guidelines; caffeine in coffee ~95 mg per 8 oz cup), environmental pollutant concentrations (drinking-water mg/L = ppm; EPA MCLs in mg/L for lead 0.015, arsenic 0.010, copper 1.3), and air-quality regulations per EPA NAAQS (CO 9 ppm 8-hr = 10 mg/m³). Convert mg to grains by multiplying by 0.01543; to grams by multiplying by 0.001.
It belongs to the metric measurement system.
Milligrams are commonly used in cooking, shipping, fitness, and scientific research.
Why Convert Ounces to Milligrams?
Converting between Ounces and Milligrams comes up in many real-world situations. Cooks adapting international recipes, shippers calculating freight costs, and fitness enthusiasts tracking body composition all need reliable weight conversions. Scientific laboratories frequently work across measurement systems when referencing global research, making quick and accurate conversion indispensable.
Frequently Asked Questions
How do I convert Ounces to Milligrams?
An imperial unit of mass equal to exactly 1/16 of an avoirdupois pound = 28. To convert Ounces to Milligrams, multiply by 28349.5. For example, 25 oz equals 708738 mg.
How many Milligrams are in 1 Ounce?
There are 28349.5 Milligrams in 1 Ounce.
How many Ounces are in 1 Milligram?
There are 0.000035274 Ounces in 1 Milligram.
What is the formula for Ounce to Milligram conversion?
The formula is: multiply by 28349.5. This means 1 oz = 28349.5 mg.
Is a Ounce bigger than a Milligram?
No. One Ounce is smaller than one Milligram because 1 oz equals 28349.5 mg, which is greater than 1.
When do you need to convert between Ounces and Milligrams?
A metric unit of mass equal to exactly 0. Ounce and Milligram are both weight units, so conversion comes up whenever one source of information uses one unit and another uses the other — a classic cross-reference challenge in engineering, trade, travel, and everyday life.