I find this handy. I like that you can adjust different parameters as your needs dictate.
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3 degree GP Top of Descent calculation:
Flight Level / 10 x 3 + wind effect + deceleration segment
- Wind effect = add 1 nm per 10 kts tailwind, reduce 1 nm per 10 kts headwind.
- Deceleration without speedbrakes = 1 nm per 10 kts in level flight / 2 nm per 10 kts during 1000 ft/min descent.
- Deceleration with speedbrakes = 0.5 nm per 10 kts in level flight and 1 nm per 10 kts in 1000 ft/min descent.
Deceleration from whatever speed you are flying above FL100 to 250 kts is already included. Deceleration from 250 kts for beginning of the approach needs to be corrected for, the rest of the deceleration is easily performed by lowering the gear and flaps on approach. Its common to intercept the glideslope at 160 kts so only need to take into account deceleration from 250 kts below FL100 to 160 kts or so.
Example:
FL300
Airport elevation 0ft
Average 20 kts tail wind
Deceleration from 250 to 160 for approach in descent:
300 / 10 = 30 x 3 = 90 nm
Wind = 20 kts / 10 = 2 nm
Deceleration = 90 kts / 10 x 2 = 18 nm
Total = 90 + 2 + 18 = 110 nm
Job done, no calculator needed 
If you want to declutter even further from the above and take deceleration from 250 kts to 160 kts as a standard just add 10 nm in level flight or 20 kts in descent for deceleration, its not an exact science anyway, so:
FL / 10 x 3 + wind effect + 10 or 20 nm.
Works in the real world, been using it everyday and it is fairly accurate. Looking at that calculator it seems like it is using those exact same rules, so no need to open an internet browser while in the sim 
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Learn to fly, not to be a passenger. A little bit of mental maths won‘t hurt for sure ^^
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Depending on what aircraft you fly there are tools to support you on the TOD calculation.
- The FBW A32NX has a TOD calculator that is synced to the FMC.
- The GNS530/GNS430 mod has a VNAV page which even more comfortably lets you enter some data based on your route and shows you the time until you need to start your descent - VERY nice!
I’m not sure if there’s something for the G1000 and G3000 yet.
The TOD calculator might be cool, but using in-cockpit tools if available is less immersion-breaking for sure 
It was just a quick little tool that can do a few cool things, calm down everyone. Man, a bunch of real bad ■■■ sim pilots here…lol
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Many ways to achieve this.
My favorite is Little Nav Map, gives you TOD and TOC points on the route, and happen to coincide (mostly) with when default ATC tells you to begin TOD. TOC is a little bit different story, as the step ups are a bit abrupt.
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Check out this cool TOD calculator I found:
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Thanks for the link, unless it is a piece of downloadable software, I do not believe it is going to be very useful. The app developers may be using this to drive web traffic to the site. When flying looking at a website to calculate TOD is immersion breaking and also there are other very good software that can be used to do the same job.
In true Flight Simmer fashion I just threw money (ten bucks) at the problem and use Sporty’s E6B App for iPhones. 
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The Working Title G3000 has a TOD calculator built-in. Bring up the flightplan, enter the altitude for the 1st waypoint of the STAR or approach where you need to be at a specific lower altitude, then select the waypoint before that and hit the VNAV button. Presto, TOD calculated and shown on the magenta line.
Otherwise, it’s pretty simple to do in your head. First, decide what rate of descent you want. Next, note the difference between your current altitude and the altitude you need to be at for a given waypoint, and divide this by your rate of descent. This tells you how many minutes before the waypoint that you need to start descending (assuming you keep your groundspeed more or less constant throughout). So then just wait until your ETE is within a minute or 2 of the required descent time, and start descending then.
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TOD calculator: Altitude x3 then remove 3 noughts. ie. Altitude 30,000’ x3 = 90,000 remove 3 noughts = 90 nm . Start descent 90 nm from arrival airport.
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MODERATOR EDIT:
And this one That I do right, I go down a little more before
E essa que faço da certinho,desço ate um pouco mais antes 
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with a vertical speed 5 times the ground speed. Indeed nothing easier than that rule of thumb.
It’s a good idea to collect a number of these rules of thumb and remember them, they are constantly used in (real) flight and work out well enough. When used with common sense it’s all you need and makes many ipad apps and flight computer obsolete.
An E6B is a great tool for many things anyway, not only TOD! Have it with you anytime.
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Getting up to let my dog in and out breaks immersion, too! 
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very much depends
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That’s pretty funny! Did you notice the pilot’s eye when he saw the cat?
My ■■■■■ cat is the same, meow on a particularly difficult approach asking for dinner! 
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I think that was well worth the ten dollars you spent for the E6B, money well spent like a professional!
I don’t know what that has to do with TOD calculators but my goodness, that’s one calm and collected cat. They do like to be up in high places!
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