How can I calculate how much an option would be worth after X days if the underlying stock changed by +/- $Y?
"You'd need to know the delta and the theta of the option. You can either calculate them yourself using a model like Black-Scholes (assuming you have a market price and can imply a volatility, and know the other factors that go into the model) or, you can see if your broker quotes ""greeks"" as well (mine does). The delta is the sensitivity (rate of change in value) to the underlying stock price, and the theta is the sensitivity to time passing (usually expressed in $/day).  So if your option has a delta of .5 and a theta of -.04, when one day passes and the underlying stock goes up $3, the option will gain roughly $1.50 due to the underlying stock price and lose $0.04 due to time passing."
"There is no fundamental, good reason, I think; ""that's just how it's done"" (which is what all the other answers seem to be saying, w/o coming out and admitting it). Just guessing, but I'll bet most of the reason is historical: Before up-to-the-moment quotes were readily available, that was a bit tedious to calculate/update the fund's value, so enacted-laws let it be done just once per day.  (@NL7 quotes the security act of 1940, which certainly has been updated, but also still might contain the results of crufty rationales, like this.) There are genuinely different issues between funds and stocks, though: One share of a fund is fundamentally different from one share of stock: There is a finite supply of Company-X-stock, and people are trading that piece of ownership around, and barter to find an mutually-agreeable-price.  But when you buy into a mutual-fund, the mutual-fund ""suddenly has more shares"" -- it takes your money and uses it to buy shares of the underlying stocks (in a ratio equal to its current holdings).  As a consequence: the mutual fund's price isn't determined by two people bartering and agreeing on a price (like stock); there is exactly one sane way to price a mutual fund, and that's the weighted total of its underlying stock.  If you wanted to sell your ownership-of-Mutual-Fund-Z to a friend at 2:34pm, there wouldn't be any bartering, you'd just calculate the value based on the stated-value of the underlying stock at that exact moment. So: there's no inherent reason you can't instantaneously price a mutual fund.  BUT people don't really buy/sell funds to each other -- they go to the fund-manager and essentially make a deposit-or-withdraw.  The fund-manager is only required by law to do it once a day (and perhaps even forbidden from doing it more often?), so that's all they do. [Disclaimer: I know very little about markets and finance. But I recognize answers that are 'just because'.]" "I'm not a financial expert, but saying that paying a $1 dividend will reduce the value of the stock by $1 sounds like awfully simple-minded reasoning to me. It appears to be based on the assumption that the price of a stock is equal to the value of the assets of a company divided by the total number of shares. But that simply isn't true. You don't even need to do any in-depth analysis to prove it. Just look at share prices over a few days. You should easily be able to find stocks whose price varied wildly. If, say, a company becomes the target of a federal investigation, the share price will plummet the day the announcement is made. Did the company's assets really disappear that day? No. What's happened is that the company's long term prospects are now in doubt. Or a company announces a promising new product. The share price shoots up. They may not have sold a single unit of the new product yet, they haven't made a dollar. But their future prospects now look improved. Many factors go into determining a stock price. Sure, total assets is a factor. But more important is anticipated future earning. I think a very simple case could be made that if a stock never paid any dividends, and if everyone knew it would never pay any dividends, that stock is worthless. The stock will never produce any profit to the owner. So why should you be willing to pay anything for it? One could say, The value could go up and you could sell at a profit. But on what basis would the value go up? Why would investors be willing to pay larger and larger amounts of money for an asset that produces zero income? Update I think I understand the source of the confusion now, so let me add to my answer. Suppose that a company's stock is selling for, say, $10. And to simplify the discussion let's suppose that there is absolutely nothing affecting the value of that stock except an expected dividend. The company plans to pay a dividend on a specific date of $1 per share. This dividend is announced well in advance. Everyone knows that it will be paid, and everyone is extremely confidant that in fact the company really will pay it -- they won't run out of money or any such. Then in a pure market, we would expect that as the date of that dividend approaches, the price of the stock would rise until the day before the dividend is paid, it is $11. Then the day after the dividend is paid the price would fall back to $10. Why? Because the person who owns the stock on the ""dividend day"" will get that $1. So if you bought the stock the day before the dividend, the next day you would immediately receive $1. If without the dividend the stock is worth $10, then the day before the dividend the stock is worth $11 because you know that the next day you will get a $1 ""refund"". If you buy the stock the day after the dividend is paid, you will not get the $1 -- it will go to the person who had the stock yesterday -- so the value of the stock falls back to the ""normal"" $10. So if you look at the value of a stock immediately after a dividend is paid, yes, it will be less than it was the day before by an amount equal to the dividend. (Plus or minus all the other things that affect the value of a stock, which in many cases would totally mask this effect.) But this does not mean that the dividend is worthless. Just the opposite. The reason the stock price fell was precisely because the dividend has value. BUT IT ONLY HAS VALUE TO THE PERSON WHO GETS IT. It does me no good that YOU get a $1 dividend. I want ME to get the money. So if I buy the stock after the dividend was paid, I missed my chance. So sure, in the very short term, a stock loses value after paying a dividend. But this does not mean that dividends in general reduce the value of a stock. Just the opposite. The price fell because it had gone up in anticipation of the dividend and is now returning to the ""normal"" level. Without the dividend, the price would never have gone up in the first place. Imagine you had a company with negligible assets. For example, an accounting firm that rents office space so it doesn't own a building, its only tangible assets are some office supplies and the like. So if the company liquidates, it would be worth pretty much zero. Everybody knows that if liquidated, the company would be worth zero. Further suppose that everyone somehow knows that this company will never, ever again pay a dividend. (Maybe federal regulators are shutting the company down because it's products were declared unacceptably hazardous, or the company was built around one genius who just died, etc.) What is the stock worth? Zero. It is an investment that you KNOW has a zero return. Why would anyone be willing to pay anything for it? It's no answer to say that you might buy the stock in the hope that the price of the stock will go up and you can sell at a profit even with no dividends. Why would anyone else pay anything for this stock? Well, unless their stock certificates are pretty and people like to collect them or something like that. Otherwise you're supposing that people would knowingly buy into a pyramid scheme. (Of course in real life there are usually uncertainties. If a company is dying, some people may believe, rightly or wrongly, that there is still hope of reviving it. Etc.) Don't confuse the value of the assets of a company with the value of its stock. They are related, of course -- all else being equal, a company with a billion dollars in assets will have a higher market capitalization than a company with ten dollars in assets. But you can't calculate the price of a company's stock by adding up the value of all its assets, subtracting liabilities, and dividing by the number of shares. That's just not how it works. Long term, the value of any stock is not the value of the assets but the net present value of the total future expected dividends. Subject to all sorts of complexities in real life." "The real question is what can you NOT do!  If you track all your monetary actions, you know everything about your monetary situation.  That means you have the tools to ask and answer ""what if"" questions, such as: ""If I get a 10% raise, could I take longer vacations?""  You could calculate how much you spend per day on vacation and then consider the amount of your raise and how much of it you'd need to allocate to vacations to, say, be able to take a two-week vacation instead of a one-week vacation. ""How much more would I have to earn to move to this nicer apartment?""  This may seem like a simple question, but a surprising number of people can't answer it in a reliable way, because they don't have a clear understanding of how much money they make and how much of it they can afford to spend on housing.  If you find you have lots of spare income, maybe you can move to the nicer place right away; if not, at least you can get a sense of how much more money you'd need to make it happen. ""If I started taking the bus to work, how much would I save?""  You can look at how much you spend on gas and compare that to the price of a bus pass.  By separating out categories like gas, repairs, and car insurance, you can also calculate different scenarios, like if you still kept your car but only used it for occasional trips, versus if you sold the car and used only public transportation. ""If I want to take a trip to Tahiti, what can I cut back on to save the money?""  Using your table you can pencil out scenarios like ""Suppose I stop eating out for lunch at work and just bring my lunch, how long would I have to do that to save enough to pay for a plane ticket?"" These are just a few random examples.  The general idea is that with a record of hard numbers, you can start to consider potential tradeoffs in an objective way --- that is, you can ask ""how much in category X would I have to give up to gain this thing I want in category Y?"" The real trick in making use of your data is not so much ""what"" you can do, but ""how"" exactly to do it.  You may have to become more of a spreadsheet wizard to really delve into these questions.  Also, if you have programming expertise, you can even use something like Python to do calculations that might be laborious in a spreadsheet." "The answer to the question, can I exercise the option right away? depends on the exercise style of the particular option contract you are talking about. If it's an American-style exercise, you can exercise at any moment until the expiration date. If it's an European-style exercise, you can only exercise at the expiration date. According to the CME Group website on the FOPs on Gold futures, it's an American-style exercise (always make sure to double check this - especially in the Options on Futures world, there are quite a few that are European style): http://www.cmegroup.com/trading/metals/precious/gold_contractSpecs_options.html?optionProductId=192#optionProductId=192 So, if you wanted to, the answer is: yes, you can exercise those contracts before expiration. But a very important question you should ask is: should you? Option prices are composed of 2 parts: intrinsic value, and extrinsic value. Intrinsic value is defined as by how much the option is in the money. That is, for Calls, it's how much the strike is below the current underlying price; and for Puts, it's how much the strike is above the current underlying price. Extrinsic value is whatever amount you have to add to the intrinsic value, to get the actual price the option is trading at the market. Note that there's no negative intrinsic value. It's either a positive number, or 0. When the intrinsic value is 0, all the value of the option is extrinsic value. The reason why options have extrinsic value is because they give the buyer a right, and the seller, an obligation. Ie, the seller is assuming risk. Traders are only willing to assume obligations/risks, and give others a right, if they get paid for that. The amount they get paid for that is the extrinsic value. In the scenario you described, underlying price is 1347, call strike is 1350. Whatever amount you have paid for that option is extrinsic value (because the strike of the call is above the underlying price, so intrinsic = 0, intrinsic + extrinsic = value of the option, by definition). Now, in your scenario, gold prices went up to 1355. Now your call option is ""in the money"", that is, the strike of your call option is below the gold price. That necessarily means that your call option has intrinsic value. You can easily calculate how much: it has exactly $5 intrinsic value (1355 - 1350, undelrying price - strike). But that contract still has some ""risk"" associated to it for the seller: so it necessarily still have some extrinsic value as well. So, the option that you bought for, let's say, $2.30, could now be worth something like $6.90 ($5 + a hypothetical $1.90 in extrinsic value). In your question, you mentioned exercising the option and then making a profit there. Well, if you do that, you exercise your options, get some gold futures immediately paying $1350 for them (your strike), and then you can sell them in the market for $1355. So, you make $5 there (multiplied by the contract multiplier). BUT your profit is not $5. Here's why: remember that you had to buy that option? You paid some money for that. In this hypothetical example, you payed $2.30 to buy the option. So you actually made only $5 - $2.30 = $2.70 profit! On the other hand, you could just have sold the option: you'd then make money by selling something that you bought for $2.30 that's now worth $6.90. This will give you a higher profit! In this case, if those numbers were real, you'd make $6.90 - $2.30 = $4.60 profit, waaaay more than $2.70 profit! Here's the interesting part: did you notice exactly how much more profit you'd have by selling the option back to the market, instead of exercising it and selling the gold contracts? Exactly $1.90. Do you remember this number? That's the extrinsic value, and it's not a coincidence. By exercising an option, you immediately give up all the extrinsic value it has. You are going to convert all the extrinsic value into $0. So that's why it's not optimal to exercise the contract. Also, many brokers usually charge you much more commissions and fees to exercise an option than to buy/sell options, so there's that as well! Always remember: when you exercise an option contract, you immediately give up all the extrinsic value it has. So it's never optimal to do an early exercise of option contracts and individual, retail investors. (institutional investors doing HFT might be able to spot price discrepancies and make money doing arbitrage; but retail investors don't have the low commissions and the technology required to make money out of that!) Might also be interesting to think about the other side of this: have you noticed how, in the example above, the option started with $2.30 of extrinsic value, and then it had less, $1.90 only? That's really how options work: as the market changes, extrinsic value changes, and as time goes by, extrinsic value usually decreases. Other factors might increase it (like, more fear in the market usually bring the option prices up), but the passage of time alone will decrease it. So options that you buy will naturally decrease some value over time. The closer you are to expiration, the faster it's going to lose value, which kind of makes intuitive sense. For instance, compare an option with 90 days to expiration (DTE) to another with 10 DTE. One day later, the first option still has 89 DTE (almost the same as 90 DTE), but the other has 9 DTE - it relatively much closer to the expiration than the day before. So it will decay faster. Option buyers can protect their investment from time decay by buying longer dated options, which decay slower! edit: just thought about adding one final thought here. Probabilities. The strategy that you describe in your question is basically going long an OTM call. This is an extremely bullish position, with low probability of making money. Basically, for you to make money, you need two things: you need to be right on direction, and you need to be right on time. In this example, you need the underlying to go up - by a considerable amount! And you need this to happen quickly, before the passage of time will remove too much of the extrinsic value of your call (and, obviously, before the call expires). Benefit of the strategy is, in the highly unlikely event of an extreme, unanticipated move of the underlying to the upside, you can make a lot of money. So, it's a low probability, limited risk, unlimited profit, extremely bullish strategy." I have an example of a trade I made some time ago.  By entering the position as a covered call, I was out of pocket $5.10, and if the stock traded flat, i.e. closed at the same $7.10 16 months hence, I was up 39% or nearly 30%/yr. As compared to the stock holder, if the stock fell 28%, I'd still break even, vs his loss of 28%. Last, if the stock shot up, I'd get 7.50/5.10 or a 47% return, vs the shareholder who would need a price of $10.44 to reflect that return. Of course, a huge jump in the shares, say to $15, would benefit the option buyer, and I would have left money on the table. But this didn't happen. The stock was at $8 at expiration, and I got my 47% return. The option buyer got 50 cents for his $2 bet.  Note, the $2 option price reflected a very high implied volatility. "This chart concerns an option contract, not a stock. The method of analysis is to assume that the price of an option contract is normally distributed around some mean which is presumably the current price of the underlying asset. As the date of expiration of the contract gets closer the variation around the mean in the possible end price for the contract will decrease. Undoubtedly the publisher has measured typical deviations from the mean as a function of time until expiration from historical data. Based on this data, the program that computes the probability has the following inputs: (1) the mean (current asset price) (2) the time until expiration (3) the expected standard deviation based on (2) With this information the probability distribution that you see is generated (the green hump). This is a ""normal"" or Gaussian distribution. For a normal distribution the probability of a particular event is equal to the area under the curve to the right of the value line (in the example above the value chosen is 122.49). This area can be computed with the formula:  This formula is called the probability density for x, where x is the value (122.49 in the example above). Tau (T) is the reciprocal of the variance (which can be computed from the standard deviation). Mu (μ) is the mean. The main assumption such a calculation makes is that the price of the asset will not change between now and the time of expiration. Obviously that is not true in most cases because the prices of stocks and bonds constantly fluctuate. A secondary assumption is that the distribution of the option price around the mean will a normal (or Gaussian) distribution. This is obviously a crude assumption and common sense would suggest it is not the most accurate distribution. In fact, various studies have shown that the Burr Distribution is actually a more accurate model for the distribution of option contract prices." You would have paid $880.00 plus commission in this case, and made $85 before commissions. How much you would have made on expiration depends on the price that TSLA has on April 1, which hasn't come yet.  If it expires worthless, you typically don't pay a commission but you will have lost the full $880.  If it expires in the money and you want to exercise it, then you would pay a commission (often different than the commission to buy/sell the option itself) and you would have 100 shares of TSLA.  You won't know how much you make or lose in this case until you ultimately sell the shares of TSLA. This is exactly how I started, starting a simulation account on the CBOE website just to see what situation was profitable because it was all greek to me. Actually after learning the greeks, I realize that site was worse and eventually read some books and got better tools. The screenshot you have is telling you the strikes, but unfortunately they are showing you the technical name of the contract on the exchanges. For example, just like you type in AAPL to buy shares of AAPL stock, you can type in VIX1616K16E to get that one particular contract, expiration and strike. So lets break it down just by inferring, because this is what I just did with that picture: You know the current price of VIX, $17.06 Calls expiring November 16th, 2016:  What is changing? SYMBOL / YEAR / EXPIRATION DAY / STRIKE / OPTION-STYLE (?) So knowing that in the money options will be more expensive, and near the money options will be slightly cheaper, and out the money will be even cheaper, you can see what is going on, per expiration.