The cleanest way to understand what DTE actually buys is to hold everything else still. Same underlying, same strike, same directional view — change only the expiry, and watch what happens to the trade.
This is the first of the two dials. By the end of this lesson you should be able to look at an expiry and know what it is charging you for, and what it is giving you in return.
The setup
GOOGL closed at 332.60. The 340 call sits about 2.2 percent out of the money, and it is listed across several expiries. Here is what the market charged for that identical strike at four distances from expiration.
| DTE | Premium | Delta | Gamma | Theta | Implied vol |
|---|---|---|---|---|---|
| 1D | $0.41 | 0.129 | 0.0330 | −0.677 | 36.6% |
| 4D | $1.03 | 0.211 | 0.0330 | −0.326 | 25.2% |
| 6D | $2.17 | 0.289 | 0.0279 | −0.361 | 28.7% |
| 11D | $3.48 | 0.341 | 0.0233 | −0.277 | 27.2% |
Four patterns are visible immediately, and each one matters.
Premium rises with time. Eleven days costs eight and a half times what one day costs. Time is the product you are buying, and the market prices it steeply.
Delta rises with time. The same strike is more responsive with more days left, because there is more opportunity for price to travel there. At one day the market gives this strike roughly a 13 percent chance of mattering; at eleven days, 34 percent. Delta is not a fixed property of a strike — it is a statement about the strike and the time remaining.
Theta per day falls with time. Not in total, but per day. The one-day contract bleeds more than twice as fast as the eleven-day contract.
Implied volatility is not flat across expiries. The one-day contract carries 36.6 percent against the eleven-day's 27.2 percent. Short-dated options frequently price higher volatility — the market knows a single session can produce an outsized move, and charges for it. You are not only paying for less time, you are often paying a higher rate for it.
The profit curve
Now apply a directional move and see what each contract pays. This assumes the move happens immediately, so only delta and gamma are working — no time passes, no volatility change.
GOOGL 340C — dollars gained and percent return
| DTE | Paid | +$0.50 | +$1 | +$2 | +$5 |
|---|---|---|---|---|---|
| 1D | $0.41 | +6 / +15% | +14 / +33% | +32 / +78% | +117 / +281% |
| 4D | $1.03 | +12 / +11% | +23 / +23% | +50 / +48% | +153 / +149% |
| 6D | $2.17 | +15 / +7% | +30 / +14% | +63 / +29% | +181 / +83% |
| 11D | $3.48 | +17 / +5% | +34 / +10% | +72 / +21% | +200 / +57% |
Each cell carries two numbers, and they tell opposite stories.
Read the percentages down any column and the short-dated contract wins every single time. On a two dollar move it returns 78 percent against the eleven-day contract's 21 percent.
Read the dollars down the same column and the ranking reverses completely. That same two dollar move produces 32 dollars from the one-day contract and 72 dollars from the eleven-day.
Neither number is honest on its own. The tension between them is the subject of the next lesson.
Where gamma starts to matter
Look at the +$5 column. The one-day contract returns 281 percent, dramatically more than anything else on the board. That is gamma.
At one day to expiry, gamma is 0.0330 and the premium is only 41 cents. As price climbs toward 340, delta rises quickly, and because it rises from a tiny premium base the percentage effect is violent. A contract that began at 13 delta can finish deep in the money inside a session.
Notice that the one-day and four-day contracts have almost identical gamma — 0.0330 each — yet behave completely differently. Gamma alone does not explain the difference. What differs is the base: the same absolute gain divided by 41 cents rather than $1.03. Convexity feels explosive at short DTE largely because the denominator is small.
This is the genuine appeal of short-dated options, and it is not imaginary. What it requires is that the move be large and immediate.
Can I just use delta times the move to estimate the gain?
Yes, for small moves, and it is more accurate than you might expect. Estimating the change as delta times the move, plus half of gamma times the move squared, lands within 2 percent of a full repricing for moves up to about two dollars on this chain — at every DTE tested.
It breaks down exactly where you would expect. On a five dollar move the approximation understates the one-day contract's gain by about 10 percent, the four-day by 4 percent, and the eleven-day by almost nothing.
That pattern is worth internalising: the approximation fails where gamma is largest, which is the same reason short-dated contracts behave so differently. When someone tells you a rule of thumb "stops working on big moves", the honest version is that it stops working on big moves in short-dated contracts specifically.
What the expiry ladder is really selling
Strip away the numbers and each expiry is selling a different product.
This framing catches a common error. Traders often pick DTE by price — "I can afford the four-day" — rather than by thesis. But the expiry is a statement about when you believe the move happens, and it should be chosen from your evidence about timing, not from your budget.
If your analysis says "this breaks within a couple of sessions", the six-day contract is the honest expression. If it says "this is building and will eventually resolve", the one-day contract contradicts your own thesis no matter how attractive its percentage column looks.
A note on strike availability
One practical constraint the textbooks skip: the contract you want may not exist.
GOOGL lists strikes every $2.50 on Friday expiries but only every $5.00 on the Monday and Wednesday weeklies. SPY, by contrast, lists daily expiries with $1 strikes. On SPY you can dial delta and DTE almost continuously. On GOOGL you take what is listed.
This matters more than it sounds. A framework that recommends "delta 0.60 at 5 DTE" is useless if that combination is not quoted on your underlying. Always check what exists before deciding what is optimal — availability constrains selection before preference does.
The trade-off in one line
More DTE costs more premium and returns a lower percentage. What it buys is that the move does not have to happen today.
That is the entire DTE axis. Everything in the next two lessons is a consequence of it.
Try it yourself — switch the lab to "same strike, vary DTE" and drag the move slider while leaving days at zero. Then drag days forward and watch the ordering change.