Formula Cost Time Machine

Compare what the same formula cost then with what it costs now.

Use identical formula quantities with historical and current package data to see direct product-cost drift, percentage change and the largest contributor. The full comparison is free, browser-local and available without registration.

Interactive comparison requires JavaScript. The methodology, worked example, assumptions, limitations and FAQ below remain available without it.

Enable JavaScript to use the Formula Cost Time Machine. The methodology and worked example remain available below.

Formula labels, dates, component identity, notes, prices, quantities, service prices and results stay in this mounted browser component. They are not written to localStorage, sessionStorage, IndexedDB, cookies or URLs and are not sent in calculator network requests or analytics. Reloading or leaving clears them.

How the comparison works

Historical and current costs are calculated separately from the package data you enter. The formula quantity never changes between the two sides.

Historical direct product cost

Divide historical package price by compatible package quantity.
Multiply that exact unit cost by the formula quantity used.
Round each line half-up to cents, then add displayed lines.

This reproduces cost from the historical data entered.

Current equivalent direct product cost

Divide current package price by compatible package quantity.
Multiply that exact unit cost by the same formula quantity.
Round each line half-up to cents, then add displayed lines.

This shows what the same quantities cost with current data.

Worked example

This fictional three-component formula uses identical quantities on both dates. Only package price or size changes.

Fictional historical and current formula-cost comparison
Component	Quantity	Historical line cost	Current line cost	Change	Change (%)
Colour	20 g	A$8.11	A$11.31	+A$3.20	+39.5%
Developer	10 ml	A$5.70	A$6.90	+A$1.20	+21.1%
Additive	10 g	A$1.50	A$1.65	+A$0.15	+10.0%
Total		A$15.31	A$19.86	+A$4.55	+29.7%

Assumptions and limitations

Same formula quantities: Historical and current calculations always use the same entered quantity for each component.
User-entered prices and package sizes: The tool does not look up, estimate or verify supplier prices or dated package data.
Direct product cost only: Labour, overhead, tax, fees and other costs are not deducted. Service-price context does not show profit.
No causal isolation: Drift reflects the exact old-versus-new unit-cost comparison. It does not isolate price change from package-size change.
No mass-to-volume conversion: Mass and volume remain separate because no product density is assumed.
No historical overwrite: This public comparison cannot edit a saved formula, create a client, set lineage or write price-history records.

Frequently asked questions

Does this change my saved formula?

No. This public tool is a browser-local comparison and cannot read or overwrite a TintLedger formula.

Can it convert mass to volume?

No. Compatible mass units can convert to mass, and compatible volume units can convert to volume. Density is never inferred.

Is the amount remaining profit?

No. This tool shows direct product-cost percentages only. Labour, overhead, tax, fees and other costs are not included.

Does TintLedger automatically reprice formula history?

No. Saved formula cost snapshots preserve their historical values. Current prices may be used for future decisions without rewriting the original.

Keep the original cost. Use current prices for future decisions.

TintLedger preserves the original formula cost while allowing current prices to be used for future decisions.

Start preserving formula history

This CTA opens onboarding. Anonymous tool data is not saved or assigned to a client, and formula-history handoff remains inactive.