GQ GMC-300S
A basic, cheap beta-gamma counter for checking background levels and hobby samples. Buy it to learn, not for emergencies.
Amazon $55.98$55.98
The GQ GMC-300S is the better geiger counter overall, rated 2.8 to 2.6. The GQ GMC-300S leads on features, sensitivity and price. The GQ GMC-300S costs $24.01 less ($55.98 vs $79.99).
Prices were last checked November 9, 2026. Product prices and availability are accurate as of that date and are subject to change; the price and availability shown on Amazon or the retailer's site at the time of purchase apply. As an Amazon Associate we earn from qualifying purchases.
FNIRSI GC-03
A cheap combined radiation and EMF meter for casual checks around the house. It is not a precise radiation instrument.
Amazon $79.99$79.99
Which should you buy?
- Choose the GQ GMC-300S for features (data logging vs none of the listed features), sensitivity (132 CPM per µSv/h (Co-60) vs 80 CPM per µSv/h (Co-60)) and price ($55.98 vs $79.99).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every beta-gamma geiger counters geiger counter; a clear win is highlighted. How we rank explains each one.
| Factor weight | GQ GMC-300S | FNIRSI GC-03 |
|---|---|---|
| Overall rating | 2.8/5 | 2.6/5 |
| Sensitivity 25% | 21 132 CPM per µSv/h (Co-60) | 10 80 CPM per µSv/h (Co-60) |
| Radiation types 20% | 40 gamma, X-ray, beta | 40 gamma, X-ray, beta |
| Dose-rate range 15% | 17 reads up to 328 µSv/h | 50 dose-rate range not published (neutral score used) |
| Features 15% | 35 data logging | 0 none of the listed features |
| Price 15% | 100 $55.98 | 90 $79.99 |
| Warranty 10% | 0 warranty not published, scored as none | 0 warranty not published, scored as none |
Specifications
| GQ GMC-300S | FNIRSI GC-03 | |
|---|---|---|
| Detection | ||
| Detector | GM tube | GM tube |
| Tube or crystal | - | J321 / M4011 GM tube |
| Radiation types | β γ X | β γ X |
| Sensitivity | 132 CPM per µSv/h (Co-60) | 80 CPM per µSv/h (Co-60) |
| Max dose rate | 328 µSv/h | - |
| Energy range | 100 to 3,000 keV | 48 to 1,500 keV |
| Gamma spectrum | No | No |
| Features | ||
| Data logging | Yes | No |
| Connection | None | None |
| Battery | 3.7 V rechargeable Li-ion | 1500 mAh rechargeable lithium |
| Build | ||
| Weight | - | 141 g |