Why Stock Tracking Matters for Art Schools

Materials are typically the second or third largest cost in an art school after staff and premises. Unlike fixed costs, materials costs are variable and directly influenced by how you manage them. A studio that tracks its stock carefully can identify waste, negotiate better prices, avoid emergency purchases, and maintain consistent margins. A studio that does not track stock operates on guesswork, and guesswork in art materials management almost always means overspending.

The challenge is that art materials are diverse. A single art school might stock dozens of different items: multiple types of clay, a range of glazes, various papers and boards, paints in several media (acrylic, oil, watercolour), brushes, inks, printmaking supplies, textiles, adhesives, and specialist items for specific projects. Each has a different unit cost, a different consumption rate, a different shelf life, and a different supplier. Managing this without a system is a recipe for waste and frustration.

This guide provides a practical framework for tracking your materials stock, calculating your true per-class costs, setting up efficient reorder processes, and using your data to improve margins over time.

Per-Class Costing: Knowing Your Numbers

The foundation of good stock management is knowing exactly what each class costs to deliver in materials. Without this number, you cannot price your classes accurately, you cannot identify which classes are profitable and which are running at a loss on materials, and you cannot spot trends in consumption over time.

How to Calculate Per-Class Materials Cost

For each class type you offer, create a materials list. Include every item consumed or partially consumed in a typical session. For each item, record the purchase cost per unit, the quantity used per session, and the cost per student per session. Here is an example for a children's pottery class with 10 students:

Stoneware clay (500g per student): £0.45 per student
Glaze (20ml per student): £0.15 per student
Kiln shelf paper (shared): £0.05 per student
Cleaning materials (shared): £0.10 per student
Kiln electricity (pro-rata per firing): £0.80 per student (assuming 20 pieces per firing and two firings per piece)
Total per student per session: approximately £1.55
Total per class of 10: approximately £15.50

Compare this to an adult oil painting class with 8 students (assuming materials are provided):

Canvas board (one per student): £2.50 per student
Oil paints (shared tubes, estimated use): £1.80 per student
Brushes (amortised cost, based on replacement every 20 sessions): £0.30 per student
Solvents and mediums (shared): £0.40 per student
Total per student per session: approximately £5.00
Total per class of 8: approximately £40.00

The difference is striking: the oil painting class costs more than twice as much per student in materials as the pottery class. If both classes are priced the same, the oil painting class has significantly thinner margins unless you charge a materials surcharge.

Supplier Management and Reorder Points

Once you know your per-class consumption, you can calculate how much stock you need for a term and set up reorder points to prevent both stockouts and over-ordering.

Calculating Term Requirements

Multiply your per-class consumption by the number of sessions per term and the number of classes per week. If you run three pottery classes per week for a 10-week term with 10 students each, you need:

Clay: 500g x 10 students x 3 classes x 10 weeks = 150kg per term
Glaze: 20ml x 10 students x 3 classes x 10 weeks = 6 litres per term

Add a 15% to 20% buffer for waste, mistakes, and variations in student usage. This gives you your term order quantity.

Setting Reorder Points

A reorder point is the stock level at which you place a new order. Set it based on your consumption rate and your supplier's delivery lead time. If you use 15kg of clay per week and your supplier takes one week to deliver, set your reorder point at 30kg (two weeks' supply, providing a one-week buffer). If your supplier's delivery time is unreliable, increase the buffer.

Supplier Diversification

Do not rely on a single supplier for critical materials. If your sole clay supplier has a stock issue or delivery delay, your pottery classes stop. Maintain accounts with at least two suppliers for your highest-volume materials (clay, paper, paint). Even if you buy predominantly from one supplier for the price advantage, test orders with your backup supplier each term so you can switch quickly if needed.

Waste Tracking

You cannot reduce waste if you do not measure it. Implement a simple waste tracking system to identify where materials are being lost and what can be done about it.

Categories of Waste

Process waste: Clay trimmings, paint left on palettes, ink remaining after printing. This is partly unavoidable but can be minimised with better session planning and material management techniques.
Failure waste: Kiln explosions, cracked pots, failed prints. Track the failure rate by class and tutor. A consistently high failure rate in one class may indicate a technique issue rather than a materials problem.
Spoilage: Materials that expire or become unusable before they are consumed. Glazes that settle and cannot be reconstituted, paint that dries out in the tube, paper that gets damp. Proper storage and stock rotation (first in, first out) minimise spoilage.
Overuse: Students using more material than necessary for the project. This is the most controllable category. Pre-portioning materials for each session (giving each student a measured amount of clay or a controlled palette of paint) significantly reduces overuse.

Tracking Method

A simple weekly log maintained by each tutor is sufficient. At the end of each session, the tutor notes any significant waste: '3 pots exploded in bisque firing' or 'half a bag of clay dried out in storage'. Review these logs monthly to spot patterns. If one class consistently generates more waste than others, investigate why. The goal is not zero waste (that is unrealistic in art education) but a downward trend and a waste rate you can factor into your costing.

Margin Analysis

With per-class costs and revenue data, you can calculate the true margin on every class you offer and make informed decisions about pricing, class mix, and materials strategy.

Calculating Class Margins

For each class, calculate: Revenue per session (number of students x fee per student) minus direct costs (tutor cost per session + materials cost per session + room cost per session, if applicable) equals gross margin per session.

A children's pottery class charging £12 per child with 10 children generates £120 per session. If the tutor costs £30 per hour (for a one-hour session), materials cost £15.50, and the room cost is £10, the gross margin is £64.50 per session, or 54%.

An adult oil painting class charging £18 per person with 8 students generates £144 per session. If the tutor costs £35, materials cost £40, and the room cost is £10, the gross margin is £59 per session, or 41%.

Despite the higher per-head revenue, the adult oil painting class has a lower margin because of the higher materials cost. This analysis might prompt you to increase the oil painting fee, introduce a materials surcharge, or switch to a model where adult students bring their own materials.

Trending Over Time

Track your margins by class type each term. Rising materials costs (which have been a consistent trend in recent years) will erode margins if prices remain static. Review pricing annually against your actual costs, not against what you charged last year.

Key Takeaways

Calculate your per-student, per-session materials cost for every class type and use it as the basis for pricing decisions.
Set reorder points based on weekly consumption and supplier lead times, with a buffer for delivery delays.
Maintain accounts with at least two suppliers for critical materials to avoid supply chain disruption.
Implement a simple weekly waste log and review it monthly to identify patterns and reduce losses.
Calculate gross margins for every class type and review them each term against actual costs.
Use margin analysis to make informed decisions about pricing, materials surcharges, and class mix.