An exchange rate between two goods is the quantity of one that settles one unit of the other, and without money it should come from recorded trades with several groups, with labour-hours as a floor and not a rule. Check rates for consistency across three goods, because inconsistent quotes let a middleman profit by cycling goods through them, and the gap can persist only if moving the goods costs more than the gap.
Part of Negotiation from Strength
How a settlement arrives at workable barter rates, with the arithmetic that exposes inconsistent quotes and the weakness of effort-based pricing.
A Rate Is a Ratio, So Quote It Both Ways
The parent article says that without money every trade is a barter negotiation and that baseline rates reduce friction. Its illustration is a kilogram of salt valued at roughly 5 kg of grain. That figure is illustrative and not a measured rate, and every figure in this article is hypothetical; the arithmetic is the point.
If 1 kg salt = 5 kg grain, then 1 kg grain = 1 / 5 = 0.2 kg salt. Quote both directions, and fix the unit (weight standard, and condition) so both sides mean the same thing; see Trade & Currency for standard weights.
Method: Let Trades Set the Rate
Step 1: Keep a rate book. For each trade record the date, partner, goods and quantities.
Step 2: Compute the rate from each trade (quantity given / quantity received) and note the spread across trades.
Step 3: Post a working rate near the middle of the recent range, and review it each season.
Step 4: Test for consistency (below) whenever you deal in three or more goods.
Step 5: Adjust for condition and distance. Quote different rates for different grades.
The parent article’s approach, letting the market establish rates when several groups agree, is the right start; the book is how you know they agree.
Consistency Across Three Goods
Take hypothetical goods: salt, grain and dried meat.
- Group X trades 1 kg salt for 5 kg grain, and 5 kg grain for 2 kg dried meat. Chained, 1 kg salt = 2 kg meat at X.
- Group Y offers 1 kg salt for 1.5 kg dried meat.
Cycle: pay Y 1.5 kg meat for 1 kg salt; sell the salt to X for 5 kg grain; sell the grain to X for 2 kg meat. You started with 1.5 kg meat and ended with 2. The gain is 2 - 1.5 = 0.5 kg meat per cycle, or 0.5 / 1.5 = 0.33, about a third, on the stake.
What it shows: when two groups quote inconsistent rates, a middleman can profit, and each cycle pushes the rates toward consistency (the buyer of Y’s salt bids it up). If you are the trader at Y, expect your quote to move. If you are the one quoting, check your rates against what you know of the neighbours.
Why Gaps Persist: The Cost of Moving Goods
A gap does not disappear if closing it costs more than it earns. Suppose carrying the goods round the cycle costs the equivalent of 0.6 kg meat in labour and risk. Then 0.5 gain - 0.6 cost = -0.1, a loss, and the inconsistency stays. Distance, risk and spoilage therefore set a band within which differing rates can coexist. This is the arithmetic behind the rule of thumb that rates differ more between distant groups than between close ones.
Labour-Hours: A Floor, Not a Rule
The parent article suggests anchoring to labour-hours, so a day’s work roughly equals a day’s work in trade value. That is a poor rule. A buyer pays for what a good gives them, not for the effort it cost. An hour of rare skill can be worth a day of ordinary work to a buyer who has no alternative, and a week spent on something the buyer already has is worth little. It also sits oddly beside the same article’s advice to let the market set rates.
Used as a floor it works: if making 1 unit of a good takes you 2 labour-days and the rate returns goods you could make in 1 labour-day, you lose a day on each trade. Unless those goods are ones you cannot make at all, refuse or ask for more. The floor tells you when to decline, not what to charge.
Condition and Units
Weight is not value when condition varies. Grain’s mass includes water. Taking moisture as the share of the wet mass: 100 kg of grain at 14% moisture holds 86 kg of dry matter, and at 20% it holds 80 kg. The wetter lot gives 86 - 80 = 6 kg less dry matter, which is 6 / 86 = 0.07, about 7% less, for the same quoted weight. Agree on condition as well as weight, and test it; wet grain also spoils faster. Quote a rate per grade, and see Barter Protocols for inspection.
Limits
- Rates move with the season. The same good costs more when it is scarce; revise.
- Rates move with who is desperate. A buyer in need pays more; see the parent article on not showing desperation. Taking advantage of desperation wins one trade and costs a neighbour.
- A book needs trades. In a new relationship there is no history; start with small trades.
- Only your own arithmetic is shown. No source in the corpus gives real rates; do not copy the numbers above.
Common Mistakes
- Fixing a rate for years.
- Quoting one direction only.
- Ignoring grade and moisture.
- Forgetting the cost of carrying.
What’s Next
- Learn next: Barter Protocols — carrying out the exchange
- Combine with: Comparative Advantage — why trade pays