ZOPA: the zone of possible agreement and how to find it
ZOPA (Zone Of Possible Agreement) is the range of terms acceptable to both sides. It sits between the seller's and the buyer's reservation prices. If a ZOPA exists, a deal is possible and the question is where in that range you land. If it does not, change the terms, add variables, or walk away to your BATNA.
Definition of ZOPA
Imagine a seller who will not license software for less than $80,000 and a buyer who will pay at most $100,000. The zone of possible agreement is $80,000 to $100,000. Any price in that range is better than no deal for both sides.
Howard Raiffa popularised the concept in The Art and Science of Negotiation (1982).
How ZOPA relates to BATNA
The edges of the ZOPA are the parties' reservation prices, and reservation prices come from their BATNAs. Improve your BATNA and you move your edge, narrowing the zone in your favour. Learn the other side's BATNA and you learn where their edge is.
How to estimate ZOPA when the limits are hidden
- 01Gather market data: average prices, benchmarks, public deals.
- 02Assess the other side's alternatives: who else could they go to, and on what terms.
- 03Ask about constraints: budget, deadlines, internal approvals.
- 04Watch concessions: the size and speed of their concessions signal how close they are to their limit.
- 05Make trial offers as packages and see what meets resistance.
What to do when there is no ZOPA
If your minimum is above their maximum on a single variable, the deal is impossible as framed. But negotiations are rarely about one number. Add variables: payment terms, volume, contract length, guarantees, revenue share. Trading across variables often creates a ZOPA where none existed.
If that still fails, walk away to your BATNA. Declining a deal outside the ZOPA is the right call, not a defeat.
Common ZOPA mistakes
- 01Revealing your reservation price: the other side will push the deal right to your edge.
- 02Assuming the ZOPA is fixed: its edges move with information and alternatives.
- 03Bargaining on price only: you lose the chance to widen the zone with other variables.
ZOPA in NEGOTIA
Every AI opponent in NEGOTIA has hidden limits and its own BATNA. You watch trust and pressure change and learn to read where its limit lies. The Revenue Share scenario is a good drill for widening the ZOPA with extra variables.
FAQ
How is ZOPA different from BATNA?
BATNA is your alternative without a deal. ZOPA is the overlap of acceptable terms for both sides, defined by their BATNAs.
Can I know the exact ZOPA?
Almost never; the other side's limits are hidden. You estimate it from the market, alternatives and behaviour at the table.
Where in the ZOPA should I aim to settle?
Near the other side's edge. A strong first anchor, slow concessions and objective justification help.
Practise this in the simulator
Negotiate with an AI opponent using this technique and get a 0–100 score with a breakdown of your mistakes. Your first 3 simulations are free.