Long put calculator defined-risk downside, and what it costs
Buying a put is the defined-risk way to be bearish, and the standard way to hedge shares you already own. You pay a premium for the right to sell at the strike; the most you can lose is that premium, and you profit as the underlying falls below your breakeven.
Outlook: Bearish
Max profit
—
best case at expiry
Max loss
—
worst case at expiry
Breakeven
—
where the trade turns even
Net debit / credit
—
to open the position
Your long put
Per-share premiums. One contract = 100 shares.
100 shares per contract
Profit at expiryLoss at expiryBreakevenStrikes & spot
How a long put pays
Breakeven = strike − premium paid
Max loss = premium paid × 100 × contracts (capped)
Max gain = (strike − premium) × 100 × contracts (stock to zero)
P/L at expiry = (max(0, strike − price) − premium) × 100 × contracts
Cheaper than shorting, and safer. Shorting stock carries unlimited risk and a borrow cost. A put caps your loss at the premium and needs no margin beyond it.
Your gain is large but not unlimited. A stock can only fall to zero, so the maximum is the strike less the premium — substantial, but bounded.
Puts are usually more expensive than calls. Equity puts typically carry higher implied volatility than equivalent calls, because demand for downside protection is persistent.
Worth naming. Buying puts as insurance works, but it is not free insurance. Held continuously, the premium drag can cost more over a year than the drawdown it was bought to avoid. Hedges are best sized and timed deliberately, not left on permanently.
What this does not model
Every figure here is the payoff at expiry. Before then your position is marked at market prices that still carry time value, so a trade can show a loss while sitting exactly where you wanted it — falling implied volatility alone will do that.
For the live version — real Greeks, current marks and what-if scenarios against actual
chain data — that is what the GreeksView desk does, in your
browser, on your own broker keys.
Frequently asked questions
What is the breakeven on a long put?
The strike minus the premium paid. Buy the 100 put for $3.80 and you break even at $96.20 — the stock has to fall below that at expiry for the trade to make money.
Is buying a put better than shorting the stock?
It is different, not strictly better. A put caps your loss at the premium and needs no stock borrow, which matters on hard-to-borrow names. But it decays, and it needs the move to happen before expiry. Shorting has no expiry but carries unlimited risk and ongoing borrow costs.
What is the maximum profit on a long put?
The strike minus the premium, times 100 per contract — realised if the underlying goes to zero. On a 100 strike bought for $3.80, that is $9,620 per contract. Bounded, unlike a long call, because a share price has a floor.
Why does my broker show a different number than this calculator?
Because you are comparing a mark-to-market value against an expiry value. Until expiry your options still carry time value, and your broker prices them at what the market will pay right now. Time passing, or implied volatility falling, can show a loss on a position that would be profitable if expiry were today.
Are commissions included in these numbers?
No — every figure is gross. On multi-leg positions this matters more than people expect: four legs to open and four to close is eight commissions against what may be a couple of hundred dollars of credit. Check your broker's per-contract rate against the max profit shown here before deciding a trade is worth putting on.
Run this against a live chain
GreeksView builds positions from real option chains with live Greeks, gamma exposure
and what-if scenarios — in your browser, on your own broker keys.