Why Units Matter
Hemp ingredient COAs, product specifications, formulation records, and supplier quotes all report cannabinoid content — and they don’t always use the same units. Procurement professionals and formulators who can’t translate between unit systems are flying partially blind: they may be comparing incompatible figures, making incorrect quantity calculations, or accepting ingredients that don’t match their actual specification.
This guide covers the unit systems you will encounter in B2B hemp ingredient transactions, how to convert between them, and the common error points where unit confusion creates real problems.
The Four Common Unit Systems
1. Percentage (%) by Weight
Percentage by weight is the most common unit on hemp ingredient COAs. When a COA reports "CBD: 78.4%," it means 78.4 grams of CBD per 100 grams of extract.
Percentage is typically used for:
- Distillate and crude extract (where cannabinoids are a fraction of total extract weight)
- Reporting relative to dry weight for crop compliance testing
- Comparing extract potency across suppliers
Important: Percentage by weight does not tell you how many milligrams are in a specific container without knowing the weight of that container's contents.
2. Milligrams per Gram (mg/g)
Milligrams per gram is mathematically equivalent to percentage — 1% = 10 mg/g — but is often used in B2B ingredient contexts because it's easier to work with for lot-level quantity calculations.
Conversion: % to mg/g
% × 10 = mg/g
Example: 78.4% CBD × 10 = 784 mg/g CBD
Conversion: mg/g to %
mg/g ÷ 10 = %
Example: 784 mg/g CBD ÷ 10 = 78.4% CBD
3. Milligrams per Milliliter (mg/mL)
Milligrams per milliliter is used for liquid extracts, tinctures, and any hemp ingredient in liquid form. This is a volume-based unit rather than a weight-based unit, so converting between mg/g and mg/mL requires knowing the density of the liquid.
For hemp distillate and most hemp extract oils, density is approximately 0.9–1.0 g/mL, depending on cannabinoid concentration, carrier oil type, and temperature. You cannot assume that 1 mg/mL equals 1 mg/g without verifying density.
Conversion: mg/g to mg/mL
mg/g × density (g/mL) = mg/mL
Example: 784 mg/g CBD × 0.92 g/mL density = 721 mg/mL CBD
When density matters most: Formulations specifying a target mg/mL concentration for a finished liquid product (tincture, beverage, topical) need density data from the supplier to calculate accurately. This is a routine request that qualified suppliers should be able to fulfill.
4. Milligrams per Serving (mg/serving)
Milligrams per serving is the unit most commonly used on finished product labels and in consumer-facing communications. It is calculated from the mg/g or mg/mL concentration and the serving size (mass or volume of extract used per dose).
Conversion: mg/g to mg/serving
mg/g CBD × grams of extract per serving = mg CBD per serving
Example: 50 mg/g CBD × 0.5 grams per serving = 25 mg CBD per serving
For ingredient buyers building formulations, this is the calculation that connects ingredient specification to finished product label claim. If your target label claim is 25 mg CBD per gummy, and your gummy formula uses 0.5g of extract per piece, you need extract at 50 mg/g CBD.
Total THC Compliance: Units in the Federal Formula
The November 12, 2026 compliance standard uses two different unit systems for two different parts of the standard:
For hemp ingredients (dry weight basis): 0.3% total THC (or 3 mg/g total THC) using the formula:
Total THC = delta-9 THC + (THCA × 0.877)
For finished products: 0.4 mg total THC per container (not per serving, per container).
These are not the same standard. A hemp distillate at 0.2% total THC (fully compliant as an ingredient) could still produce a finished product that exceeds 0.4 mg per container, depending on how much distillate is used per container.
Example calculation:
- Distillate: 0.2% total THC = 2 mg/g total THC
- Gummy: uses 0.3g of distillate per piece, 30 pieces per container
- Total THC per container: 2 mg/g × 0.3g × 30 = 18 mg total THC per container
- 18 mg >> 0.4 mg limit → non-compliant finished product
This is the critical math that trips up formulators who focus only on ingredient-level compliance. The finished product standard (0.4 mg/container) is far more stringent than the ingredient standard (0.3%), and the conversion must be calculated for each specific formulation.
The 0.877 Conversion Factor Explained
When THCA (tetrahydrocannabinolic acid) is heated — as occurs in gas chromatography testing — it decarboxylates to delta-9 THC. The 0.877 factor represents the mass ratio of THC to THCA: THCA has a higher molecular weight than THC (358 g/mol vs. 314 g/mol), so when THCA converts to THC, it loses mass. Specifically, 358 grams of THCA converts to approximately 314 grams of THC — a ratio of 314/358 = 0.877.
This is why HPLC testing is required for accurate total THC calculation under the federal framework: HPLC reports THCA and delta-9 THC as separate compounds, allowing the 0.877 conversion to be applied accurately. GC testing converts THCA to THC during the analysis, preventing separate reporting and making the total THC calculation impossible to perform correctly.
Common Unit Conversion Errors
Treating mg/g and mg/mL as equivalent. These units are only equal when density is exactly 1.0 g/mL. For most hemp extracts, density is 0.88–0.95 g/mL, making a 10–12% error if units are swapped without density correction.
Applying the ingredient THC limit to finished products. The 0.3% (3 mg/g) ingredient standard and the 0.4 mg/container finished product standard are completely different. Using the ingredient standard to assess finished product compliance produces incorrect results.
Forgetting that % is by weight, not volume. A label claiming "1% CBD" means 1g per 100g of product — not 1g per 100 mL. For liquids, these are different numbers unless density is exactly 1.0 g/mL.
Quick Reference Card
| To convert | To | Formula |
|---|---|---|
| % | mg/g | % × 10 |
| mg/g | % | mg/g ÷ 10 |
| mg/g | mg/mL | mg/g × density |
| mg/mL | mg/g | mg/mL ÷ density |
| mg/g | mg/serving | mg/g × grams/serving |
| THCA % | delta-9 THC equivalent % | THCA% × 0.877 |
Low Gravity Hemp supplies hemp ingredients with fully documented COAs in both % and mg/g formats. Density certificates available for liquid extract products.
