Lab Scale Buying Guide: The Right Readability for Each Type of Lab
Reviewed by MNM Scales technicians · Updated November 3, 2026 · Prices checked November 3, 2026
Short answer: pick a lab scale by the smallest amount you weigh, then by capacity. Teaching and general labs do well with 0.01 g, such as the A&D EK-300i at $359. QC, formulation and compounding labs usually need 0.001 g, such as the A&D EJ-303 at $345. R&D and assay work needs 0.1 mg, such as the A&D HR-100A at $939. If anything is sold or charged by weight, choose an NTEP model. Buy it calibrated with a certificate: call (832) 290-3120.
This guide is for school and university labs, QC and formulation labs, pharmacies, cannabis labs and R&D teams buying a lab scale. MNM Scales has sold, calibrated and repaired scales and balances for over 30 years from our shop in Cypress, Texas, and we are one of the largest scale distributors. MNM Scales is an authorized A&D Weighing dealer.
Lab scale picks by type of lab
| Type of lab | Typical readability | What to look for | Our pick |
|---|---|---|---|
| School and teaching labs | 0.01 g | Durable pan, simple keys, counting and percent modes | A&D EK-300i |
| QC, formulation and sample prep | 0.001 g | Breeze break, fast settling, PC or printer output | A&D EJ-303 or A&D FX-200iN |
| Pharmacy compounding | 0.001 g, NTEP Class II | Legal-for-trade approval, comparator, records | A&D FX-323N; see our pharmacy balance guide |
| Cannabis labs and dispensaries | 0.001 g to 0.01 g, NTEP | Class II approval where product is sold by weight | A&D FX-200iN; see our cannabis scales guide |
| R&D, assays and standards | 0.1 mg | Enclosed weighing chamber, internal or external calibration | A&D HR-100A or A&D HR-250AZ |
School and teaching labs: 0.01 g
Classroom and general lab work, such as weighing reagents for a demonstration or checking sample masses, is a good fit for a 0.01 g lab scale. The A&D EK-300i ($359) weighs 300 g x 0.01 g on a 110 mm stainless steel pan, with 0.01 g repeatability and ±0.02 g linearity in A&D’s specifications. It has a backlit LCD, a sealed keypad, counting, percent weighing and a HI/OK/LO comparator, and RS-232C comes standard. A battery pack (EKW-09i, not included) makes it portable between benches. It uses external calibration, so plan on a calibration weight (not included) or a yearly calibration from us.
QC, formulation and sample prep: 0.001 g
When you weigh additives, actives or small samples, milligram readability matters and air currents start to move the reading. The A&D EJ-303 ($345) weighs 310 g x 0.001 g and comes with an anti-static breeze break. It runs on the included AC adapter or on four AA batteries (not included), and USB or RS-232C interfaces can be added for a PC or printer. For a faster lab balance with RS-232C standard and an NTEP certificate, the A&D FX-200iN ($649) weighs 220 g x 0.001 g and settles in about one second with A&D’s Compact Super Hybrid Sensor.
Weighing chemicals or solvents? See our chemical weighing scale guide. Sending results to a computer? See how to connect a scale to a computer.
Pharmacy and cannabis labs: NTEP Class II
If a lab or pharmacy sells, prices or charges by weight, the balance needs to be NTEP approved for that use. The A&D FX-200iN (220 g) and A&D FX-323N (320 g, $759) are both listed on NTEP Certificate of Conformance 08-045A6 (A&D FX Series, Class II, active, checked on the NCWM database on November 3, 2026), with a display of 0.001 g and a certified division of e = 0.01 g. The FX-323N is part of A&D’s Fortis series, with RS-232 and USB standard and a comparator with a buzzer for checkweighing doses or packages. For compounding rules and Class A replacements, see our pharmacy balance guide; for dispensary and testing labs, see our cannabis scales guide.
R&D, assays and standards: 0.1 mg
For assays, standards and small-sample prep, a 0.1 mg balance with an enclosed weighing chamber is the right lab scale. The A&D HR-100A ($939) weighs 102 g x 0.1 mg with external calibration, and the A&D HR-250AZ ($1,349) weighs 252 g x 0.1 mg and calibrates itself with a built-in weight at the touch of a key. A&D lists about 2 seconds to stabilize in FAST mode, a shatterproof, anti-static breeze break with rotary doors that lifts off for cleaning, a front illuminated level bubble, a 90 mm pan and RS-232C standard. The HR-100A uses a 100 g or 50 g calibration weight (not included).
Need finer than 0.1 mg? Compare classes in our microbalance vs semi-micro guide. Deciding between 0.1 mg and 0.001 g? See our comparison of the two balance types, and browse analytical and lab balances.
Internal or external calibration on a lab scale
- External calibration: you place a known weight on the pan when the balance asks for it. It costs less up front and suits labs with a steady room and a calibration weight on hand.
- Internal calibration: a built-in weight adjusts the balance at the touch of a key, which helps where temperature changes during the day or many users share one balance.
- Either way, a yearly calibration with a certificate documents accuracy. More detail: internal vs external calibration balances.
Lab scale models compared at live prices
| Model | Capacity x readability | Calibration | Interface | Best for | Price |
|---|---|---|---|---|---|
| A&D EK-300i | 300 g x 0.01 g | External | RS-232C | Teaching and general lab work | $359 |
| A&D EJ-303 | 310 g x 0.001 g | External | USB or RS-232C (not included) | QC and sample prep on a budget | $345 |
| A&D FX-200iN | 220 g x 0.001 g (e = 0.01 g) | External | RS-232C | Lab work and selling by weight, NTEP Class II | $649 |
| A&D FX-323N | 320 g x 0.001 g (e = 0.01 g) | External | RS-232 and USB | Compounding and packaging, NTEP Class II | $759 |
| A&D HR-100A | 102 g x 0.1 mg | External | RS-232C | Assays and standards | $939 |
| A&D HR-250AZ | 252 g x 0.1 mg | Internal | RS-232C | Shared R&D benches | $1,349 |
Setting up a lab scale for steady readings
- Use a solid surface. At 0.001 g and finer, foot traffic and fans show up in the reading; a balance table helps.
- Level it. Center the level bubble with the adjustable feet each time the balance is moved.
- Let it warm up. Leave the balance plugged in before the first calibration of the day.
- Keep the doors closed. Close the breeze break before reading 0.001 g or 0.1 mg results.
- Check it on a schedule. Use our balance maintenance checklist to log daily checks.
Rules: lab scales, NTEP and Texas
A lab scale used only for research, testing or internal formulation is chosen for its readability and repeatability. When a lab, pharmacy or dispensary sells, prices or charges by weight, use an NTEP-approved model such as the FX-200iN or FX-323N; see our NTEP guide.
Texas note: TDA does not require an NTEP certificate for every device, but the scale must meet NIST Handbook 44 and suit its use; some scales do need one, so we recommend NTEP models and can check yours. See TDA’s scales used in trade guidance (PDF) and our TDA scale certification guide, or call us or TDA to confirm your use.
Calibration and rental
- Lab scales and balances up to 2.2 kg: in-house calibration with a certificate is $95, or NIST calibration with a NIST-traceable certificate is $395. See NIST vs in-house certificates and our balance calibration service.
- On-site service: $295 + $2 per mile per visit across the Houston area, with calibration charged per balance; see on-site calibration.
- Mail-in, repairs and rentals: ship balances for mail-in calibration, have us repair the brands we sell, and rent all types of scales while yours is out of service.
Not sure which lab scale fits? Tell us the smallest amount you weigh, the largest container, and whether anything is sold by weight. We will match the balance and ship it calibrated with a certificate. Shop: 21249 FM 529 Rd, Cypress, TX 77433, visits by appointment.
Frequently asked questions
What readability do I need in a lab scale?
Match it to the smallest amount you weigh: 0.01 g for teaching and general lab work, 0.001 g for QC, formulation and compounding, and 0.1 mg for assays and standards.
What is the difference between a lab scale and a lab balance?
People use both names. Lab gear that reads 0.01 g or finer is usually called a balance, and models reading 0.1 mg have an enclosed weighing chamber.
Does a lab scale need to be NTEP approved?
A lab scale used to sell, price or charge by weight needs an NTEP-approved model, such as the A&D FX-200iN or FX-323N (CC 08-045A6, Class II). For research and testing, choose by readability and repeatability.
Should I get internal or external calibration?
Internal calibration, as on the A&D HR-250AZ, adjusts with a built-in weight at a key press. External calibration, as on the HR-100A, costs less and needs a calibration weight (not included).
What is a good lab scale for a school?
A 0.01 g balance such as the A&D EK-300i (300 g x 0.01 g) with counting and percent modes and a sealed keypad.
Can you calibrate a lab scale and provide a certificate?
Yes. Balances up to 2.2 kg are $95 for in-house calibration with a certificate or $395 for NIST calibration with a NIST-traceable certificate. Call (832) 290-3120.