What is Coin Grading?
Coin grading is the process of evaluating a coin's condition and assigning it a numeric grade on the Sheldon Scale (1-70). Professional grading services like PCGS and NGC use strict standards to assess surface preservation, strike quality, luster, and eye appeal.
CoinGrader AI uses artificial intelligence trained on thousands of professionally graded coins to provide instant pre-grading estimates, helping you make informed decisions before submitting coins to professional services.
The Sheldon Grading Scale
Circulated Grades (1-59)
- Poor (PO-1): Identifiable date and type, but heavily worn
- Fair (FR-2): Major design elements visible but well worn
- About Good (AG-3): Design elements mostly visible, heavy wear
- Good (G-4 to G-6): Major features clear, significant wear
- Very Good (VG-8 to VG-10): Design details visible, moderate to heavy wear
- Fine (F-12 to F-15): Moderate wear on high points, good detail
- Very Fine (VF-20 to VF-35): Light to moderate wear, most details clear
- Extremely Fine (EF-40 to EF-45): Light wear on highest points only
- About Uncirculated (AU-50 to AU-58): Slight wear on high points, nearly full luster
Mint State / Uncirculated Grades (60-70)
- MS-60 to MS-62: Uncirculated with numerous contact marks, below-average luster
- MS-63: Uncirculated with moderate contact marks, acceptable eye appeal
- MS-64: Choice uncirculated, few contact marks, good eye appeal
- MS-65: Gem uncirculated, minimal marks, strong eye appeal
- MS-66: Premium gem, exceptional surfaces, outstanding eye appeal
- MS-67: Superb gem, nearly perfect with minimal imperfections under magnification
- MS-68 to MS-70: Perfect or near-perfect coins (extremely rare)
Key Grading Factors
1. Surface Preservation
The most critical factor. Graders assess the number, size, and location of contact marks, scratches, and other surface imperfections.
- Marks in prime focal areas (faces, central devices) have greater impact
- Fewer marks = higher grades
- Deep gouges or scratches result in details grades
2. Strike Quality
How well the coin was struck at the mint. Full strikes show complete detail in all design elements.
- Check hair details, feather separation, and high relief areas
- Weak strikes can limit maximum grade potential
- Some dates are notoriously weak (e.g., many Peace Dollars)
3. Luster
The original mint surface texture that creates a flowing light effect. Luster can be cartwheel, satin, or proof-like.
- Original luster is essential for gem grades (MS-65+)
- Dipping or cleaning destroys natural luster
- Booming luster adds significant eye appeal
4. Eye Appeal
Overall aesthetic impression. Subjective but critical, especially for borderline grades.
- Attractive toning can enhance eye appeal
- Unattractive spots, haze, or color reduces appeal
- Can make the difference between plus and standard grades
5. Color (For Copper Coins)
Percentage of original mint red color remaining on copper coins.
- Red (RD): 95%+ original red color
- Red-Brown (RB): 5-95% original red
- Brown (BN): Less than 5% red
How to Use CoinGrader AI
Step 1: Photograph Your Coin
Quality photos are essential for accurate AI analysis:
- Use good, indirect natural light or 5000K LED lighting
- Avoid direct flash (causes hot spots and glare)
- Capture both obverse and reverse at slight angles
- Ensure sharp focus—blurry images reduce accuracy
- Fill the frame with the coin (avoid excessive background)
- Take multiple shots at different angles if unsure
Step 2: Upload to CoinGrader AI
- Log in to your CoinGrader AI account
- Click "Grade New Coin"
- Upload obverse and reverse images
- Enter coin details (date, mint mark, denomination)
- Submit for analysis
Step 3: Review AI Grade Estimate
Within seconds, you'll receive:
- Grade Estimate: Predicted grade on the Sheldon scale
- Confidence Score: How certain the AI is (higher = more reliable)
- Surface Analysis: Details about marks, luster, and strike
- Grading Recommendation: Whether the coin is worth professional grading
Step 4: Make Informed Decisions
Use AI insights to:
- Decide if the coin justifies professional grading costs (apply the 3X rule)
- Identify coins unlikely to receive gem grades (save grading fees)
- Select the appropriate PCGS/NGC service level
- Make more informed buying and selling decisions
Understanding Confidence Scores
CoinGrader AI provides confidence scores to indicate reliability:
90-100% Confidence (High)
AI is very confident. Grade estimate is highly reliable.
75-89% Confidence (Good)
AI has good confidence. Estimate is reliable but consider +/- 1 grade point.
60-74% Confidence (Moderate)
Moderate confidence. Coin may be borderline between grades. Consider additional photos.
Below 60% Confidence (Low)
Low confidence. Image quality may be poor or coin has unusual characteristics. Retake photos or consult professionals.
Common Pre-Grading Mistakes to Avoid
❌ Poor Photo Quality
Blurry, dark, or overexposed images lead to inaccurate estimates. Always use good lighting and sharp focus.
❌ Overestimating Your Coin's Grade
Collectors frequently overgrade by 1-2 points. Trust the AI estimate and confidence score.
❌ Ignoring Confidence Scores
Low confidence scores indicate uncertainty. Don't make expensive grading decisions based on low-confidence estimates.
❌ Cleaning Coins Before Analysis
Never clean coins. Cleaning destroys value and results in details grades from professional services.
Ready to Grade Your Coins?
Start using CoinGrader AI today to get instant, accurate grade estimates and make smarter collecting decisions.