Gold & Silver Calculator Methodology
Imperial Time's gold and silver calculators estimate the indicative intrinsic precious-metal value of an item from its weight, stated purity and a current market reference. They are designed as transparent valuation tools, not as guaranteed purchase offers.
How the calculation works
The core formula is:
Indicative intrinsic value = weight in grams × metal purity × current fine-metal value per gram.
For example, 9 carat gold is commonly marked 375 and contains 37.5% fine gold, so its purity factor is 0.375. Sterling Silver 925 contains 92.5% fine silver, so its purity factor is 0.925.
Gold and silver market references
The calculator uses current reference pricing for fine gold or fine silver and converts the reference into pounds sterling per gram. Precious metals are commonly quoted per troy ounce, so the calculation uses the standard conversion of 1 troy ounce = 31.1034768 grams.
The calculator and the value-per-gram tables are designed to use the same reference object so the figures shown on a page remain aligned. Market prices and foreign-exchange rates can change during the trading day, and third-party market data can occasionally be delayed or temporarily unavailable.
Purity and hallmark factors
For gold, Imperial Time's calculator supports common UK fineness marks including 375 (9ct), 585 (14ct), 750 (18ct), 916 (22ct) and 999 (24ct/fine gold). For silver, it supports common fineness levels including 500, 800, 900, 925 Sterling Silver, 958 Britannia Silver and 999 fine silver.
A hallmark is useful evidence of stated fineness, but it does not by itself guarantee the composition, authenticity or sale value of an item. Imperial Time may test and inspect an item before confirming any valuation or offer.
Why intrinsic value is not the same as a dealer offer
Intrinsic or melt value estimates the value of the precious-metal content itself. A purchase offer can differ because of testing, refining costs, market movements, condition and other commercial factors. Conversely, a complete item can be worth substantially more than its raw metal content.
Signed or branded jewellery, luxury watches, diamond or gemstone-set pieces, antique and period jewellery, collectable coins and objects with unusual craftsmanship, rarity or provenance should not automatically be valued as scrap. Imperial Time can assess the complete item before you decide how to sell it.
Who reviews this methodology?
This methodology is reviewed by Imperial Time's Jewellery & Precious Metals Team. Imperial Time UK Ltd has traded since 2015 and provides specialist valuations from 79 Kensington Church Street, London W8 4BG.
How often are references updated?
The live calculator requests current market references when a visitor opens the tool. Imperial Time is also developing a server-side reference layer so key values can be rendered directly into the page before browser JavaScript runs. Where a recent cached reference is used because a live request is temporarily unavailable, the calculator is designed to label that state rather than imply a stale price is current.
Historical price information
Historical charts on Imperial Time calculator pages are intended to show reference-price movement over time rather than predict future prices. Historical performance is not a guarantee of future precious-metal prices or the amount that a dealer may offer for an item.
Use the calculators
Gold Scrap Calculator UK · Silver Scrap Calculator UK · Gold & Silver Scrap Metal Calculator UK
Request a specialist valuation
For an item-specific assessment, visit Sell Gold in London, Sell Silver & Precious Metals or Sell to Imperial Time.