Postage / Stamp Calculator
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Philately (stamp collecting) is one of the world’s oldest hobbies, and collections can range from sentimental value to significant monetary worth. Estimating the value of a stamp collection requires identifying each stamp, finding its catalog value, and applying a condition discount.
Formula: Estimated Market Value = Σ(Catalog Value × Condition Multiplier × Rarity Factor) Collection Total = Σ(Individual Stamp Values) Dealer Offer Estimate = Collection Total × 0.25 to 0.50 (dealers buy at 25–50% of retail)
What each variable means:
- Catalog Value — the price listed in the Scott Catalog (U.S. standard) or Stanley Gibbons (UK standard). This is the retail asking price, not the sale price.
- Condition Multiplier — condition is the biggest value driver in philately:
- Mint Never Hinged (MNH): 100% of catalog
- Mint Original Gum (MOG): 70–90%
- Very Fine Used (VFU): 60–80%
- Fine Used: 30–50%
- Good Used (heavy cancel): 10–25%
- Damaged (tears, thins, creases): 5–15%
- Rarity Factor — scarce items can exceed catalog value; common modern stamps often trade far below catalog.
Condition grading scale (APS standard):
- Superb (98): flawless centering, fresh color, perfect gum
- Extremely Fine (90): near-perfect
- Very Fine (80): well-centered
- Fine-Very Fine (75): slightly off-center
- Fine (70): noticeably off-center but complete design
Worked example: A 1918 U.S. 24¢ Jenny airmail stamp (normal, not the famous invert). Scott catalog value: ~$600 (used, Fine). Condition: Very Fine Used → multiplier 0.75. Estimated value = $600 × 0.75 = $450
Most family collections of common 20th-century stamps are worth $50–$500 total. Rare pre-1900 mint stamps can be worth thousands.