Long Put Calculator
A long put breaks even at the strike minus the premium paid, costs you the full premium anywhere above the strike, and gains as the underlying falls — capped only by the stock reaching zero. Enter your numbers to see where those lines sit.
The arithmetic
A put gives you the right to sell 100 shares at the strike. You pay the premium up front, and — as with a long call — that premium is the entire downside.
- Breakeven = strike − premium paid. The default $100 put at $3.50 breaks even at $96.50.
- Max loss = premium × 100 × contracts, incurred anywhere at or above the strike.
- Max profit = (strike − premium) × 100 × contracts, reached only if the stock goes to zero. Unlike a call, a put's upside has a hard ceiling, because the underlying cannot fall below nothing.
Two different jobs, one structure
Puts get bought for two unrelated reasons and the distinction matters for how you should read this chart.
As a directional bet, the put stands alone and the chart above is the whole story: you need the stock below breakeven by expiration or the premium is gone.
As insurance on shares you own, the put is only half the position, and reading its payoff in isolation is misleading — a put that expires worthless while your shares rallied is insurance that did its job. Model that properly on the protective put calculator, which includes the stock leg.
Puts are usually more expensive than the equivalent call
For most equity underlyings, downside strikes carry higher implied volatility than upside strikes — the volatility skew. In practice a put 5% below the money often costs noticeably more than a call 5% above it. That does not make puts a bad trade, but it does mean the breakeven on a put is typically further from the current price than a symmetric intuition suggests. Type real premiums from your own chain rather than assuming symmetry.
Time decay works against you here too
Long options of either flavour lose time value as expiration approaches. A slow grind down can leave a put holder with a loss despite being right about direction. The expiration chart above cannot show that.
Where the 100x multiplier comes from
Product specification, not convention: OCC defines a standard equity option as covering 100 shares, premium quoted in points where one point is $100[1] — so a $1.85 premium costs $185, and every payoff here applies that multiplier to the leg structure.
One exception is worth knowing about: adjusted contracts, covered on the options profit calculator.
Calculating it is the easy half
A long put prices out in one line of arithmetic. The payoff is arithmetic — anyone can run it. What it cannot show is whether you believed the trade when you put it on, or are describing a winner picked out of a month of noise.
That is the gap kappi closes: the position committed before the fact, sealed and timestamped on a log nobody can edit afterwards. A screenshot of this chart proves you can use a calculator; a sealed commit proves you took the trade. $15/month, no free tier.
Sources
Frequently asked questions
What is the maximum profit on a long put?
(Strike − premium) × 100 per contract, reached only if the underlying goes to zero. Unlike a call, a put's profit is capped because the price floor is zero.
What is the breakeven on a long put?
Strike minus the premium paid per share. A $100 put bought for $3.50 breaks even at $96.50 at expiration.
Why do puts cost more than calls at the same distance from the money?
Volatility skew. In equity markets, downside strikes usually price at higher implied volatility than upside strikes, so the put is more expensive.
Should I use this to model a hedge on shares I own?
No — use the protective put calculator, which includes the stock leg. A hedging put's payoff read on its own leaves out the position it is protecting.