Gold Impurity Calculator (Tola) — Alloy Mass for South Asian Pieces
The tola-input variant of the gold impurity calculator returns alloy/impurity content in tola, masha and ratti — matching the units local jewellers use to settle refining trade-ins. A 5 tola 22K piece contains 0.417 tola (4 masha) of alloy that will not survive refining to 999 fine gold.
Knowing the impurity figure before sending pieces to a refiner protects against undervaluation and lets you compare quotes between refiners on a like-for-like basis.
When to use this calculator
- Refiner trade-in pre-check
- Family-piece valuation before resale
- Karachi/Mumbai Sarafa settlement
Impurity Content in South Asian Tola Units
When sending gold jewellery to a Karachi, Lahore or Mumbai refiner, the impurity mass determines what will not come back as pure gold. For a shop that books in tola, expressing the impurity in tola/masha/ratti means the settlement figure matches the unit on the original receipt — no gram conversion is required when reconciling the refiner's payout with the customer's piece.
The calculation is identical to the gram-based impurity calculator: alloy (tola) = Gross tola × (24 − karat) ÷ 24. A 5-tola piece at 22K has 5 × 2/24 = 0.417 tola of alloy = 5 masha 0 ratti. Only the display unit differs from the gram variant.
For the same calculation with gram output — useful for international refining or export documentation — the gold impurity calculator (Grams) is the appropriate variant. For a combined view showing pure gold, alloy and live money value together, the gold analyzer (Tola) consolidates all three.
Impurity in tola
Impurity (tola) = Gross tola × (24 − karat) ÷ 24. Convert remainder to masha (× 12) and ratti (× 96) as needed.
Step-by-step calculation
Example: 3 tola of 22K gold
- 1
Calculate impurity ratio
ratio = (24 − karat) ÷ 24
(24 − 22) ÷ 24 = 2 ÷ 24 = 0.0833
- 2
Impurity in tola
alloy (tola) = gross tola × ratio
3 × 0.0833 = 0.2500 tola alloy
- 3
Express alloy as TMR
tola decimal → TMR
0.2500 tola = 3 masha 0 ratti
- 4
Pure gold in TMR
pure = gross − alloy
3.0000 − 0.2500 = 2.7500 tola = 2 tola 9 masha 0 ratti
Sample conversions
| Input | Result |
|---|---|
| 1 tola of 22K | 0.083 tola (≈1 masha) impurity |
| 2 tola of 18K | 0.5 tola (6 masha) impurity |
| 5 tola of 21K | 0.625 tola (7.5 masha) impurity |
Quick Reference — Impurity Content per 1 Tola by Karat
| Karat | Impurity (tola) |
|---|---|
| 24K (999) | ~0.0001 tola |
| 22K (916) | 0.0833 tola |
| 21K (875) | 0.1250 tola |
| 18K (750) | 0.2500 tola |
| 14K (585) | 0.4167 tola |
| 10K (417) | 0.5833 tola |
Impurity = Gross tola × (24 − karat) ÷ 24. Add 0.5–1% extra for actual refining process loss.
Frequently asked questions
Does the refiner pay me for the alloy mass?
Only a small credit — copper, silver and zinc trade at a fraction of gold's value. Some refiners include a fixed by-product credit; others charge a refining fee that effectively nets out the alloy value. Ask for an itemised settlement statement.
What is the impurity of 1 tola of 22K gold in masha and ratti?
22K impurity = 8.33% × 1 tola = 0.0833 tola = ~1 masha 0 ratti (exactly: 0.0833 × 12 = 0.999 masha ≈ 1 masha). For 18K: 25% × 1 tola = 0.25 tola = 3 masha exactly.
How do tola-input impurity results compare to gram-input results?
They are mathematically identical — the same karat ratio applies. The tola-input variant simply expresses results in tola/masha/ratti instead of grams. Use the tola variant when your customer, ledger and rate sheet are all in local units to avoid unit-switching mid-calculation.
Can I use this calculator to estimate how much alloy to add to reach a lower karat?
This calculator works backwards (karat → impurity content). To compute how much alloy to ADD to pure gold to reach a target karat, use the gold impurity calculator (by karat or ratti), which runs the forward calculation.
Why is 24K gold listed as having 0.10% impurity instead of 0%?
999 fineness = 99.9% pure; 9999 fineness = 99.99% pure. Even "pure" 24K commercial gold contains trace impurities from the refining process. The 0.10% figure reflects 999 (three nines) fineness — the common retail standard. Investment-grade 9999 fine gold would show 0.01%.
Related calculators
These tools cover neighbouring steps in the same workflow — pair them with this one for a complete calculation.