Carats: Gemstone Calculator

About this app

Your care and good judgment matter with every stone. Thank you for using Carats. Estimate gemstone weight, organize inventory and prepare clear quotes with tools for jewelers, gem dealers, collectors and lapidary artists.

View on the App Store

GEMSTONE WEIGHT ESTIMATES

– Estimate carat weight from measurements in millimeters.
– Find diamond, ruby, sapphire, emerald and other gemstone references.
– Choose a cut factor and review specific gravity.
– Account for girdle thickness, pavilion bulge and outline.
– Explore brilliant, step, cushion and cabochon shapes.

ADVANCED GEM AND CUSTOM CUTS

– Measure above, through and below the girdle separately.
– Set upper and lower profiles independently.
– Enter table, culet and cushion corner measurements.
– Add custom materials, species and density.
– Use measured outline area, custom factors or measured volume.

INVENTORY WITH CARATS PRO

Give each stone a record you can return to between calculations.

– Assign stock IDs and add actual photographs.
– Attach gemstone certificates as images or PDFs.
– Record suppliers, purchase costs and storage locations.
– See available, reserved and sold stock.
– Keep estimated and measured weights separate, with dates and methods.
– Choose which saved weight a customer quote uses.
– Manage parcels, matched pairs and individual stones.
– Track partial sales, physical returns and remaining quantities.

STONE COSTS AND PROFIT WITH PRO

– Include purchase, cutting, setting and shipping costs.
– Add selling fees and seller-paid commissions.
– Compare profit, markup and margin before tax.
– Keep commission income separate from selling expenses.
– Record cost corrections while keeping original sale history.

CUSTOMER QUOTES AND RECEIPTS WITH PRO

– Select several stones for one quote.
– Include photos, dimensions and the selected weight basis.
– Price by stone, carat or the whole selection.
– Add business details, a logo and quote acceptance deadlines.
– Record deposits, payments, refunds and balances.
– Share quote and receipt PDFs with internal costs kept private.
– Keep issued documents when stock details change.

CONVERSIONS AND REFERENCE

– Convert carats, grams, points and milligrams.
– Compare wire gauge sizes in inches and millimeters.
– Convert distance, area and volume units.
– Work with US gallons, Imperial gallons and liters.
– Browse gemstone density and cut factor charts.

SAVE AND REVIEW YOUR WORK

– Save reusable density and profile presets.
– Import CSV files with column mapping and a preview.
– Review row errors and duplicate stock before importing.
– Back up your workspace with photographs and saved PDFs.
– Review saved gemstone and sales statistics.
– Keep customer details and commission payment history together.
– Link stock with saved calculations and sales.
– Duplicate measurements without replacing the original record.
– Keep receipt PDFs with customer payment history.

APPLE WATCH TOOLS

– Convert weight and gauge sizes at your wrist.
– Browse guides, gemstone references and calculator graphs.
– Share results from the separate Watch app.
– Use Watch tools without a usage limit or subscription.

On iPhone and iPad, try five free calculations per day for five consecutive calendar days, up to 25 total. Your first free Calculate request starts day one. Inactive days count; unused daily calculations do not roll over. Pro adds unlimited live calculations, interactive calculator graphs and the record, inventory, document and import tools described above. Choose monthly or lifetime access. Monthly renews automatically until canceled. Existing records remain viewable, shareable and exportable without Pro.

For monthly subscriptions:
Monthly Pro is a 1-month auto-renewable subscription.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Gemstone weights are estimates based on measurements, density and cut. Use a scale for actual weight.

App Store Screenshots

Latest App Store Release Notes

Your eye for detail deserves clear records. Thank you for using Carats. This update adds inventory, stone costs, customer quotes and receipts to help you follow each sale. These management tools are included with Carats Pro.

GEMSTONE INVENTORY

– Give each stone, parcel or matched pair its own stock ID.
– Add actual photographs and certificate attachments.
– Keep supplier, acquisition cost and storage location together.
– Review available, reserved and sold quantities.
– Link stock to saved calculations and sales.
– Find records by stone, stock ID, supplier or location.

ESTIMATED AND MEASURED WEIGHTS

– Keep scale readings separate from calculated estimates.
– Record when and how each weight was obtained.
– Compare estimated and measured weight for the same selection.
– Choose the weight basis shown on a customer quote.
– Keep original observations when you record a fresh measurement.

COSTS AND PROFIT

– Include purchase, cutting, setting and shipping costs.
– Track selling fees and seller-paid commission.
– Compare profit, markup and margin before tax.
– Keep unknown acquisition costs clearly marked.
– Record dated cost corrections with a reason.
– Retain completed sale history when later costs change.

CUSTOMER QUOTES AND RECEIPTS

– Combine selected stones in a quote with photos and dimensions.
– Show the chosen weight basis and price for each selection.
– Add business details, a logo and an acceptance deadline.
– Record customer deposits, payments and refunds.
– Review the balance still due.
– Share quote and payment or refund receipt PDFs.
– Keep internal costs and commissions out of customer documents.
– Retain issued PDFs after inventory details change.

PARCELS AND MATCHED PAIRS

– Record physical quantities and total measured weight.
– Reserve stock for a customer.
– Split a matched pair when you need individual stone records.
– Move stones from a parcel into their own stock records.
– Allocate costs and track partial sales and remaining stock.
– Record physical returns separately from money refunds.

BRING YOUR SPREADSHEETS

– Match CSV columns to the inventory fields you use.
– Review a preview, row errors and duplicate stock IDs.
– Bring across sold and reserved stock with its original dates.
– Match actual photograph and certificate files before importing.
– Download sample templates to prepare your inventory.
– Back up your complete workspace, including saved media and PDFs.

REUSE MEASUREMENT SETTINGS

– Save named density and profile presets.
– Apply settings while keeping the current stone’s dimensions.
– Duplicate a stock record with its original measurement history.
– Confirm separate physical stock before using a duplicate.
– Revisit Advanced Gem measurements for custom cuts and profiles.

FREE CALCULATIONS AND PRO

– Try five free calculations a day for five consecutive calendar days.
– Start day one with your first valid free Calculate request.
– Use up to 25 calculations; inactive days still count.
– See remaining uses, calendar days and the allowance end date.
– Type and change inputs without spending a use until Calculate.
– Keep unlimited live results and interactive calculator graphs with Pro.
– Choose monthly or lifetime Pro access.
– Continue viewing, sharing and exporting existing records without Pro.

ABOUT AND APPLE WATCH

– Find support, website, privacy and terms links on About and in its menu.
– Keep weight and gauge tools close at hand on Apple Watch.
– Use the separate Watch tools and sharing without a usage limit.

Unused daily calculations do not roll over. Monthly Pro renews automatically until canceled. Gemstone weights remain estimates; use a scale for actual weight.

App Store Information

• App Store category: Utilities
• Genres: Utilities, Business
• Availability: Free
• Current version: 9.2
• Requires: iOS 17.6 or later
• Content rating: 4+
• Last updated: 2026-10-21

Developed by Verosocial. App details can change; verify the current App Store listing before publication.