Two milk businesses can charge the same price per litre and earn very different amounts, because litres are not all the same. Milk with 6% fat is worth more than milk with 3.5%, and anyone buying or selling in bulk is eventually going to be paid on quality rather than volume.
This guide covers how fat and SNF pricing actually works, the standard formulas with worked examples, why rates move through the year, and how to set rates for your own customers in a way you can defend.
Fat and SNF: what is being measured
Milk is water plus solids. The solids split into two groups:
- Fat — the butterfat. Typically 3 to 4.5% in cow milk and 6 to 8% in buffalo milk. This is what makes milk rich, and it is the most valuable single component.
- SNF (solids-not-fat) — everything else that is not water or fat: protein, lactose, minerals. Typically 8 to 9%. Less variable than fat, but it is what makes milk nutritious and it matters for anything made from milk.
Total solids is fat plus SNF. Water is the remainder, and adding water is the single most common form of adulteration precisely because it dilutes both numbers at once.
The three common pricing methods
Flat rate per litre
One price regardless of quality. Simple, universally understood, and what almost every household delivery uses. The downside is invisible: if your supply quality varies, you are absorbing the difference yourself.
Two-axis rate (fat and SNF priced separately)
The standard method at collection centres and co-operatives. Each component has its own price per kilogram of solids, and the payment is the sum.
Formula:
Amount = (Litres × Fat% × Fat rate ÷ 100) + (Litres × SNF% × SNF rate ÷ 100)
Worked example. 10 litres at 4.2% fat and 8.5% SNF, with a fat rate of 700 per kg and an SNF rate of 300 per kg:
- Fat component: 10 × 4.2 × 700 ÷ 100 = 294
- SNF component: 10 × 8.5 × 300 ÷ 100 = 255
- Total: 549, which is 54.90 per litre
Fat-only rate (the “per kg fat” method)
The simpler version, common where SNF is not measured. A single rate is paid per kilogram of fat.
Formula: Amount = Litres × Fat% × Rate ÷ 100
Worked example. 10 litres at 6.5% fat (buffalo), rate 600 per kg of fat: 10 × 6.5 × 600 ÷ 100 = 390, which is 39 per litre.
This method is quick but it ignores SNF entirely, which means a supplier can dilute slightly and still be paid nearly the same if fat holds up. Two-axis pricing is harder to game.
A quick sanity check for any rate system
Whatever method you use, work out the effective per-litre price and compare it to the flat market rate for equivalent milk. If your formula is producing a number well away from the market, one of the component rates is wrong. It is easy to set a fat rate and an SNF rate that look reasonable individually and combine into something that is not.
Why rates move through the year
Milk pricing has two separate cycles running at once, and confusing them causes most of the mistakes.
The quality cycle
Fat and SNF vary with the animal’s diet, the stage of lactation and the weather. In hot weather animals eat less and drink more, so fat percentage typically falls; in cooler months with better fodder it rises. This is why paying a flat rate per litre year-round quietly transfers money in one direction and then the other.
The supply and demand cycle
Production is generally higher in the cool months (the flush) and lower in the heat. Demand does the opposite in some places — more consumption of milk products during festival periods, less in very hot weather. Where supply is lowest and demand highest at the same time, procurement rates rise; in the flush, they fall.
The practical consequence: your cost per litre is not stable, even if your selling price is. Knowing your own thin months is worth more than any forecast — which is a good argument for keeping monthly volume and revenue figures you can look back at.
Setting rates for your own customers
Most household delivery runs on a flat rate, and that is the right call — customers want a predictable number. The judgement is in what that number is, and in how you change it.
Know your actual margin per litre
Take what you paid for the milk, add fuel, packaging and the value of your own time, and compare it to what you charge. Do this once a year at minimum. A surprising number of rounds discover that their smallest, furthest customers are served at a loss.
Have a reason for every different rate
Different rates for different customers are normal and fine — bulk, long-standing loyalty, a genuinely better product. What is not fine is a rate nobody can explain, because it will eventually be compared with a neighbour’s and you will have no answer. Write the reason down next to the rate.
Raise prices rarely, clearly, and with notice
- Once a year beats three small increases. Frequent changes feel unstable.
- Give two weeks’ notice, and do it in writing or on the bill. A rise that arrives as a surprise on a bill reads as a mistake or a trick.
- Give the reason in one sentence. “Our purchase rate has gone up” is enough. Do not over-explain.
- Raise everyone together. Selective increases get discovered and cost you more in goodwill than the extra revenue.
- Apply from a month boundary, so no bill contains two rates. If your tool cannot split a period across rates, this stops being optional.
Discount deliberately, not by drift
Rounding down, throwing in an extra half litre, letting an old low rate persist for years — these are discounts, they just are not recorded as any. Compare your total revenue divided by total litres against your list rate once a year. The gap is what you are actually giving away, and it is usually larger than anyone expects.
Frequently asked questions
How is fat percentage measured?
At collection centres, with a milk analyser that reports fat and SNF in seconds, or by the older Gerber method. For household delivery you are almost never measuring it yourself — you are buying at a tested rate and selling flat.
Why is buffalo milk more expensive per litre?
Mostly fat. At roughly twice the fat percentage of cow milk, a litre carries far more solids, so under any quality-based pricing it is worth more. Under flat pricing the difference has to be set by hand.
Can I charge some customers on fat and others flat?
Yes, and it is common — bulk buyers and shops on a quality rate, households on flat. It only works if your records hold both kinds of rate per customer, otherwise the mixed system becomes a monthly manual exercise.
What if a customer disputes the rate they are on?
Show them the bill history with the rate printed on each one. Rate disputes almost always come from a rate that was agreed verbally and never recorded anywhere.
Where to go next
For the arithmetic of the bill itself, see how to calculate a milk bill correctly. For recording it all, keeping a customer ledger that holds up. For the seasonal side of volume and demand, seasonal milk demand planning.
Milk Diary supports both flat per-litre rates and fat-based pricing per customer, and recalculates bills when a rate changes rather than making you edit entries. It is free on Google Play.