Reading a COA to Calculate THC per Serving in Hemp Edibles

Written by Sipho Sam

November 20th, 2025

Staring at a Certificate of Analysis, trying to figure out how to calculate edible potency from COA percentages, leaves you looking at lines labelled THCa and Delta-9 THC.

You might be wondering which number matters and how a gummy labelled 0.3% THC can contain 25 milligrams.

At the same time, three online calculators give you three different answers that make the math feel unreliable.

The formula everyone teaches works perfectly, but only if you start with the right information.

Calculating from a mismatched COA, confusing your units, or skipping real-world adjustments turns your number into fiction.

Conversely, verifying batch matching and understanding that percentages and milligrams tell completely different stories makes the calculation trustworthy.

This guide transforms COA confusion into calculation confidence by teaching you which lines to read.

It also touches on how to convert those numbers into milligrams per serving, and why 0.3% by dry weight can legally mean substantial THC amounts in hemp edibles.

Table of Contents

• Verify the COA Matches Your Product First

• Decode COA Abbreviations and Units

• Find the Right Potency Lines for Your Product Type

• The Baseline Calculation from COA to Milligrams Per Serving

• Adjust for THCa Conversion and Infusion Efficiency

• Three Calculations You Can Copy

• Why 0.3% Hemp Can Still Contain 10-30mg THC Per Gummy

• Cross-Check Your Number and Spot Red Flags

• Using Your THC Amount Safely and Effectively

Verify the COA Matches Your Product First

Every calculation starts with verification, not math, because the most common mistake that ruins otherwise perfect calculations involves using a COA that doesn't match the product in hand.

Check the batch number on your COA against the batch number printed on your product packaging, because different batch numbers mean you're looking at test results from a different production run entirely.

At the same time, some companies recycle old COAs for new products and show you results from months ago or from a completely different formulation.

Look for the test date on the COA, because recent dates suggest current testing practices while dates from six months or a year ago raise questions about whether results reflect what's actually in your product now.

Verify the laboratory's credentials before trusting any numbers, as ISO 17025 accreditation indicates that the lab adheres to strict quality standards and undergoes independent audits.

At the same time, the COA should clearly display the lab's name, contact information, and either a signature or a QR code for verification.

Unknown labs or missing accreditation information should raise questions about the reliability of every number on the report.

Mood makes batch verification straightforward by linking every product page to current, batch-matched lab results directly from ISO-accredited facilities, such as ACS Laboratory and New Bloom Labs.

Their COAs include full verification elements, including batch numbers, test dates, lab signatures, and accessible contact information.

Red flags that destroy calculation accuracy before you start include:

• Mismatched batch numbers

• Missing safety panels for microbials

• Pesticides, or heavy metals, unverifiable lab credentials

• Suspiciously perfect round numbers that suggest estimation rather than actual testing.

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Decode COA Abbreviations and Units

COAs speak in abbreviations and switching units that trip up even experienced readers, while understanding this language prevents the calculation errors that make your final number wildly inaccurate.

ND means "Not Detected," which is what you want to see when you see ND next to pesticides or heavy metals.

For cannabinoid lines, ND implies that the compound isn't present in measurable amounts.

LOQ stands for "Limit of Quantitation," which tells you the smallest amount the lab can measure accurately, while results below LOQ may show ND or a less-than symbol.

The units matter more than the numbers, because a COA might list THC as a percentage by weight, milligrams per gram (mg/g), milligrams per millilitre (mg/mL), or milligrams per serving, and mixing these up creates massive mistakes.

Here's the same THC content expressed in different units: 20% THC equals 200mg/g equals 0.02g/g, where each describes identical potency, so confusing percentage with mg/g makes your calculation jump by a factor of ten.

Match units to product types, as flower COAs typically use percentages by weight, beverages often show mg/mL, edibles list mg per serving, and concentrates might display any of these units depending on the lab.

When converting between units, use these relationships: 1 gram contains 1,000 milligrams, a percentage represents parts per hundred (so 20% equals 0.20 as a decimal), and to convert percentage to mg/g you multiply the percentage by 10.

Quick Reference:

• % by weight → multiply by 10 to get mg/g

• mg/g → multiply by grams to get total mg

• mg/mL → multiply by milliliters to get total mg

• Total mg → divide by servings to get mg per serving

Find the Right Potency Lines for Your Product Type

COAs from different labs organize information differently, so knowing where to look for each product type saves time and prevents reading the wrong line.

Flower COAs display cannabinoid profiles with two critical numbers, where THCa appears as the larger percentage (often between 15% and 30% for high-quality flower).

In contrast, Delta-9 THC shows as a much smaller number (typically under 0.3% for hemp products), and some COAs also display a calculated "Total THC" line that combines these using the conversion formula.

Mood's clear COA format demonstrates readable potency reporting, as their Kush Mintz strain report shows 29.01% THCa prominently, with Delta-9 THC below the 0.3% federal limit.

This format makes locating the necessary numbers straightforward.

Edible and beverage COAs typically list milligrams directly through lines labelled "mg per serving," "mg per container," or "mg per package," which provide the numbers without requiring percentage conversions, as the lab has already performed the calculations from raw material to finished product.

Concentrate COAs may show percentages in the 70-95% range or list milligrams per gram, with the format varying by concentrate type.

Distillates often display a percentage purity, and live resin or rosin may show cannabinoid profiles similar to those of flower, but with much higher numbers.

What is Total THC vs Delta-9 THC?

Delta-9 THC is the cannabinoid that exists in the plant right now.

THCa is the precursor compound that becomes Delta-9 THC through heating, and Total THC represents the maximum Delta-9 THC available after complete heating.

For products you'll heat (like flower or concentrates) Total THC gives you the relevant potency number, while for products already processed and infused (like edibles or tinctures) the reported Delta-9 THC reflects what's actually in the product.

The Baseline Calculation from COA to Milligrams Per Serving

To calculate edible potency from a COA, multiply cannabis weight in grams by 1,000, then by THC percentage, then divide by servings.

Here's the process broken into steps, where you follow each one in sequence to reach your final milligrams per serving number.

Step 1: Confirm weight and units by knowing the total weight of cannabis you're working with in grams and checking that your COA percentage matches the form you're using, because if the COA tests flower at 18% THC, that percentage applies to the flower and not to already-infused oil.

Step 2: Convert grams to milligrams by multiplying grams by 1,000, so seven grams of flower becomes 7,000 milligrams.

Step 3: Calculate total THC milligrams by multiplying total milligrams by the THC percentage as a decimal, so for 18% THC you multiply by 0.18.

Step 4: Divide by servings by taking your total milligrams and dividing by the number of servings in your recipe or product.

Worked Example: Step 1: Convert 7 grams to 7,000mg Step 2: Multiply by 0.18 THC percentage to get 1,260mg total THC Step 3: If infusing into 12 fluid ounces of coconut oil (72 teaspoons), divide 1,260mg ÷ 72 = 17.5mg per teaspoon

The quick conversion trick shows that percentage THC times 10 equals mg per gram, so 20% THC flower contains 200mg per gram, and this mental math helps you estimate quickly or verify calculator results.

What is the formula for edible potency?

The baseline formula calculates the theoretical maximum potency as (grams × 1,000) × THC percentage ÷ servings, which equals mg per serving.

In real-world results, however, this typically ranges from 70-80% of the theoretical maximum due to heating and transfer efficiency.

Adjust for THCa Conversion and Infusion Efficiency

Total THC equals THCa times 0.877 plus Delta-9 THC, a formula that accounts for the heating process in which THCa converts to Delta-9 THC.

When cannabis undergoes heating, the THCa molecule loses a small portion of its weight as carbon dioxide escapes. The

0.877 conversion factor represents this weight change, so if your COA shows 18% THCa and 2% Delta-9 THC, your Total THC calculates as 2% + (18% × 0.877) = 17.8% Total THC after heating.

Mood lists THCa and Delta-9 separately on COAs, where their THCa flower reports show both the THCa percentage (the larger number) and how it translates to Total THC after the heating process.

This transparency allows you to verify the calculations yourself or use their provided Total THC line.

Heating and infusion typically reduce cannabinoids by 20 percent, as the heating process activates potency by converting THCa to THC.

Meanwhile, transfer processes during infusion capture somewhere between 70% and 80% of the available cannabinoids.

Combining these factors means that your final product usually contains about 80% of the theoretical maximum.

Show both numbers in your calculations by first calculating the baseline using 100% theoretical efficiency and then calculating the adjusted estimate, accounting for a typical 20% loss.

This approach provides a range instead of a single number, reflecting real-world variability.

Same 7g Flower with Adjustments: Baseline calculation: 1,260mg total THC Adjusted for typical losses: 1,260mg × 0.8 = 1,008mg Per teaspoon: 1,008mg ÷ 72 = 14mg per teaspoon Your actual potency likely falls between 14mg and 17.5mg per teaspoon, depending on your heating method and infusion efficiency.

Concentrates need different starting assumptions because a distillate beginning at 85% THC contains far more cannabinoids per gram than flower at 20% THC.

The exact weight of concentrate in your recipe produces a much stronger final product; therefore, you should adjust your recipe proportionally or use specialized calculators designed for concentrate infusions.

Three Calculations You Can Copy

How do I calculate mg THC per teaspoon of infused oil?

7 grams of 18% THC flower contains 1,260mg total THC (7 × 1,000 × 0.18), which, after 20% heating loss, becomes 1,008mg, and divided across 72 teaspoons of oil, equals 14mg per teaspoon.

Complete calculation:

You're infusing 7 grams of flower testing at 18% THC into 12 fluid ounces (72 teaspoons) of coconut oil.

Step 1: Convert flower weight to milligrams, where 7 grams × 1,000 = 7,000mg of flower.

Step 2: Calculate total THC (baseline) where 7,000mg × 0.18 = 1,260mg total THC.

Step 3: Adjust for typical losses by multiplying 1,260mg by 0.8, resulting in an adjusted total of 1,008 mg.

Step 4: Divide by teaspoons, where 1,008mg ÷ 72 teaspoons = 14mg per teaspoon.

Each teaspoon of your infused oil contains approximately 14mg of THC, while a recipe calling for 3 tablespoons (9 teaspoons) would include roughly 126mg total THC.

Brownies Portioned by Weight

Your full batch of brownies weighs 800 grams and contains a total of 480mg THC after adjustments for heating and mixing.

Step 1: Calculate per-gram strength where 480mg THC ÷ 800g total weight = 0.6mg THC per gram.

Step 2: Weigh your portions by cutting brownies and weighing each piece, where a 50-gram brownie contains 50g × 0.6mg/g = 30mg THC.

This portioning method provides more consistency than cutting by eye, because weight-based portioning accounts for uneven distribution during mixing and ensures each serving contains the intended strength.

Beverage Verification

Your beverage label claims 5mg per serving with 2 servings per can (10mg total container), while the COA shows 5.2mg per serving and 10.4mg per container.

Step 1: Calculate variance where the label shows 5mg per serving, the COA shows 5.2mg per serving, and the difference of 0.2mg equals 4% over the label claim.

Step 2: Verify container total where the label shows 10mg total, the COA shows 10.4mg total, and the difference of 0.4mg equals 4% over the label claim.

These numbers fall within the typical testing variance of ±10%, so the product delivers what the label promises with slight overage that ensures customers receive at least the stated strength.

Why 0.3% Hemp Can Still Contain 10-30mg THC Per Gummy

A 5-gram gummy at 0.3% Delta-9 THC contains 15mg of THC, because federal hemp law measures percentage by dry weight and allows significant milligram amounts in heavy products.

Percentage and absolute amount measure different things, where the 0.3% limit is a ratio comparing THC weight to total product weight, so when the product itself weighs several grams, that tiny percentage translates to meaningful milligrams.

The math for common gummy weights shows that a 4-gram gummy at 0.3% equals 12mg Delta-9 THC (4,000mg × 0.003), a 5-gram gummy at 0.3% equals 15mg Delta-9 THC (5,000mg × 0.003), and a 10-gram gummy at 0.3% equals 30mg Delta-9 THC (10,000mg × 0.003).

This resolves the confusion about how compliant hemp products deliver substantial effects, because federal hemp regulations define legal hemp as cannabis containing less than 0.3% Delta-9 THC by dry weight, where the law sets a ratio limit rather than an absolute milligram limit.

Mood offers millions of users hemp-derived THC, which is 100% legal and fully compliant with cannabis.

At the same time, their products demonstrate this math in practice through Hero Dose Gummies, while staying under the 0.3% federal limit, and customers can verify the compliance math themselves using batch-matched COAs.

You may have heard that the legality of hemp-derived THC is currently under attack, which could threaten the wellness of so many.

So, read here to learn how to join the fight and help us keep hemp cannabis accessible to all for a long time to come.

What does 0.3% THC mean in milligrams?

0.3% THC means 3 milligrams per 1,000 milligrams (1 gram) of product, so you multiply product weight in milligrams by 0.003 to find total THC milligrams, which means an 8-gram gummy contains 24mg at the 0.3% limit (8,000mg × 0.003).

Cross-Check Your Number and Spot Red Flags

Compare your calculated mg per serving to the label claim if you're verifying a purchased product, as the typical variance between COA results and labels ranges within ±10%.

A label claiming 25mg with a COA showing 23mg or 27mg falls within normal testing variation.

In comparison, a label claiming 25mg with a COA showing 15mg or 40mg suggests problems.

Verify safety panels show "pass" results for microbials, heavy metals, and residual solvents before trusting potency numbers, because a COA might report accurate THC while missing contamination tests entirely.

Heavy metals or pesticides matter more to your health than exact milligram counts, while residual solvents testing becomes critical for Delta-8 and Delta-10 products, which undergo chemical conversion processes.

Double-check batch matching as your final verification step, because the batch number on the COA must match the batch number on your product.

This check should be performed at the beginning and end of your process, where you verify batch matching before calculating, and should be verified again before trusting your final number.

Run a sanity check against typical serving ranges where beginners typically start with 2.5-5mg.

Regular users often prefer doses of 10-25mg, while experienced consumers may choose 50mg or higher.

If your calculation shows 200mg per serving for a mainstream product, you should revisit your math, because that strength typically exists in products labelled explicitly as high-potency.

How accurate are edible calculators?

Edible calculators provide estimates within 10-20% of actual potency because heating efficiency, infusion transfer rates, and mixing consistency all affect final THC amounts, and no calculator accounts for every variable in your specific process.

Red flags to spot during verification include:

• Wildly mismatched numbers between label and COA (beyond ±15%)

• Missing safety tests on the COA

• Unverifiable lab credentials or contact information

• Perfect round numbers that suggest estimation rather than measurement

• Test dates from months or years ago

• Batch numbers that don't appear anywhere on your product

A perfect calculation from a fraudulent or mismatched COA remains worthless because verification bookends the entire process.

Using Your THC Amount Safely and Effectively

Typical starting amounts vary widely by experience level, where users new to edibles often begin with 2.5mg to 5mg.

Regular users who have established tolerance might prefer 10mg to 25mg, and experienced consumers familiar with their personal response may choose 50mg or higher.

Wait 90 to 120 minutes for full effects before considering taking more, because edibles process through your digestive system and liver, which takes substantially longer than inhalation.

In contrast, the impact builds gradually over the first two hours, and taking additional amounts too soon results in both portions hitting simultaneously, creating an experience stronger than intended.

Edibles feel different because your liver converts Delta-9 THC into 11-hydroxy-THC, where this metabolite produces effects distinct from inhaled cannabis.

Many users report that edibles feel more intense than smoking or vaping, even at similar THC amounts.

At the same time, the experience also lasts longer (typically 6 to 8 hours compared to 2 to 3 hours for inhalation).

Mood's exact milligram labelling and batch-matched COAs eliminate the need for calculations in finished products.

Their tiered system organizes products by potency categories (Mild, Medium, and High) to help users select the appropriate strength without performing math.

Every product page includes clear starting guidance and recommended wait times.

Informational Notice: This information is for educational purposes only. Mood is not a medical authority, and readers should consult licensed healthcare professionals for personal health decisions. Effects vary significantly between individuals based on tolerance, body chemistry, and consumption history.

Start with lower amounts than you think you need, because you can always take more in future sessions, but you cannot reduce an amount once it has been consumed.

This patient approach prevents the overwhelming experiences that result from taking additional portions before the first one fully activates.

You Now Have the Formula and the Context

You can verify COAs, extract the correct numbers from the relevant lines, calculate both baseline and adjusted estimates, and understand how hemp compliance math enables 0.3% products to contain substantial milligrams.

Both paths work where you calculate yourself for DIY projects involving infusing oils, making edibles from flower, or verifying homemade recipes.

You can do this while you trust transparent labelling when purchasing finished products that provide batch-matched COAs and clear milligram amounts.

Mood's approach provides a shortcut for those who want verification.

Without calculation through batch-matched COAs on every product page, clear milligram labelling instead of confusing percentages, and testing partnerships with ISO-accredited labs.

Where the transparency exists, whether you want to verify yourself or trust the work already completed.

You have the tools where the certificate of analysis no longer resembles random numbers; each line serves a purpose, and each calculation reveals the actual strength, so read that COA with confidence.