Estimate artwork market value and net proceeds from comparable sales, condition, provenance, work comparability, demand, selling fees, and fixed costs.
Artwork Value Formula
Use completed auction or private-sale records for works by the same artist that match medium, size, period, subject, edition, and venue. Then adjust the median for condition, provenance, comparability, and current market demand.
V = B * F1 * F2 * F3 * F4
To find the comparable-sale baseline needed to support a target adjusted value:
B = V / (F1 * F2 * F3 * F4)
Estimated net proceeds after a percentage fee and fixed costs are:
N = V * (1 - f) - C
Variables:
- V is the adjusted market value
- B is the median comparable-sale baseline
- F1 through F4 are the selected category-specific adjustment multipliers
- N is estimated net proceeds
- f is the selling fee as a decimal
- C is fixed selling, repair, shipping, or authentication cost
The result includes an indicative market range and a lower quick-sale range. These are planning estimates, not guarantees; use multiple recent comparables and remove obvious outliers before entering the median.
Artwork Value Adjustment Reference
Each selector is centered on a benchmark multiplier of 1.00. A multiplier above 1.00 raises the comparable baseline, while a multiplier below 1.00 reduces it.
| Factor | Benchmark | Adjustment range |
|---|---|---|
| Condition | Good, stable condition | 0.35× to 1.18× |
| Provenance and documentation | Limited documentation | 0.70× to 1.18× |
| Work comparability | Closely comparable | 0.60× to 1.25× |
| Current market demand | Stable demand | 0.65× to 1.20× |
Example Problems
Example 1: A set of close sold comparables has a median price of $3,000. The selected adjustments combine to 1.25.
V = 3000 * 1.25 = $3,750.00.
Example 2: You want the adjusted value to be $5,000, and the combined adjustments equal 1.15. Find the comparable baseline that would support that result.
B = 5000 / 1.15 = $4,347.83.
Frequently Asked Questions
Can a calculator authenticate artwork?
No. Authentication requires evidence such as expert opinion, catalogue raisonné research, provenance, materials analysis, and examination. The calculator only adjusts a comparable-sales baseline after attribution has been considered.
Should auction hammer price or total price be used?
Use the same convention for every comparable. Hammer prices exclude the buyer’s premium, while total prices include it. Mixing the two creates a distorted median.
How does provenance affect artwork value?
Documented ownership, exhibition, gallery, and publication history can strengthen attribution and buyer confidence. Unsupported stories should not receive the same adjustment as verifiable records.
