Data and assistant access

The calculator estimates production costs and profit for UK sublimation sellers. The public description below makes its scope and limitations readable without running JavaScript.

Calculator description (JSON) · Assistant summary · Detailed assistant notes

Units and limits

• Estimates use the current user inputs; starting figures are examples, not quotes or profit guarantees.
• Profit and production costs are per good item. Postage inputs are per order and shared across its items.
• Net margin divides profit by revenue including allocated postage after modelled sale VAT or flat-rate payment. Markup divides profit by production cost including labour.
• Rates are not live feeds. Source-check dates apply to sampled defaults, not arbitrary user edits. The interface update date is separate.
• VAT treatment and recovery are assumptions chosen by the user. The calculator does not prepare a VAT return or establish tax liability or refund entitlement.
• Currency-conversion fees, refunds and cancellations are outside the model. No separate Climate Change Levy is added to the entered electricity tariff.
• Ink use and workshop defaults are estimates; use measured use and personal cost records.

Source-check notes

• Electricity and statutory rates checked on 2026-08-26 . Ofgem's next cap takes effect 1 October 2026.
• Etsy fees checked on 2026-08-25 .

Interface updated 11 September 2026. This does not advance the source-check dates above.

Browser tools

In compatible browsers the page registers three optional WebMCP tools. Each accepts an empty object, is read-only and returns a JSON string. Ordinary calculator use does not require WebMCP.

• get_calculator_facts: Read scope, units and limitations.
• get_rates_checked_dates: Read historical source-check notes from the page.
• get_current_estimate: Read current settings, estimate, warnings and assumptions; returns no estimate for invalid or unrendered settings.

get_current_estimate reads the same settings and calculation functions as the visible interface. Amounts named _GBP are pounds per good item; percentages are percentage points. The response includes displayed rounded values alongside unrounded numeric results. break_even and target_price contain a price and resulting profit/margin, or an err message when no price is available.

If status is not ok, the estimate is null. Report the errors and fix the inputs through the calculator before using a result. The tools do not edit settings, place orders or send figures to a calculation server.

Citing an estimate

Link to the calculator, identify the inputs and per-item basis, and include the relevant warnings and source-check notes. Never present a sample result as the visitor’s actual profit. The static JSON file contains no visitor figures and cannot calculate a quote.

Privacy

The calculator code stores settings in the visitor’s browser. A compatible assistant can read them when its calculator tool is used; the assistant’s own data handling then applies. Read the privacy and saved-settings explanation.