unfold it on top of one big table, flip table over?

Volume of a cylinder = pi r^2 h. So 282.74 square feet, or 8 square metres. A square meter of 24 carat gold weighs 19.3 tonnes so the hole can fit 154.4 metric tonnes of gold. One metric tonne = 2,205lbs, so the hole can fit 340,452lbs. 50gp per pound means the hole can hold 17,022,600gp. Find a dragon horde, scoop the contents into the hole and retire.

Quote from Norks >>

Volume of a cylinder = pi r^2 h. So 282.74 square feet, or 8 square metres. A square meter of 24 carat gold weighs 19.3 tonnes so the hole can fit 154.4 metric tonnes of gold. One metric tonne = 2,205lbs, so the hole can fit 340,452lbs. 50gp per pound means the hole can hold 17,022,600gp. Find a dragon horde, scoop the contents into the hole and retire.

Forgiving your use of area units interchangeably with volume units, that's accurate if you're filling the whole thing with solid gold, but in practice you won't be.  You'll likely be filling it with gold coins, which are small, flat, and round, and as such they don't mesh together perfectly. 

Assuming:
All coins are minted to uniform size,
All coins have a thickness of 3/32" (~0.23 cm)
All coins weigh exactly 0.02 pounds
The density of gold is 19.3 g/cc

Then:
Each coin will have a diameter of just over 0.62",
11857 coins can fit in a hexagonally-pitched layer,
There are 1280 layers in 10 feet. 

Using this hexagonal method, which accounting for the dead space between coins, nets us a total 15,176,960 coins, at a maximum theoretical density of about 89%. 

If we further assume that adventurers just scoop loot into the hole instead of laying it down neatly, let's conservatively round to an even 80% of theoretical density, or 13,626,481 gold pieces.  That's still a huge amount, and more realistic lol.  And you could fit many of those into a single bullet pouch on your belt or even tuck the folded hole into your underwear or something if you wanted to keep it super secret.

Keep in mind this is about the most efficient you'll get for storing your riches, because if we apply that same 80% theoretical density for poorly-packed coins to a bag of holding, it should be able to hold over 3m gold pieces in 64 cubic feet of space, but the 500 lb weight limit limits the coinage to 25000 total coins, and not to mention that this piece of cloth is essentially weightless and a bag of holding is like 15lb. 

Question:

If you use Rope Trick inside of a Portable Hole, would a creature inside the extra-dimensional space still begin suffocating after 10 minutes?

Quote from JamesGames >>

Each time the hole is opened does it always open to the same space? This would mean that it could be used to transport objects. For example, can I open the Portable Hole, fill it with water, close it. Then in a few days open the hole again in a different location and have a swimming pool?

The description mentions a person stuck inside trying to get out, but does not say anything about using the hole to store/move things.

Quote from JamesGames >>

Each time the hole is opened does it always open to the same space? This would mean that it could be used to transport objects. For example, can I open the Portable Hole, fill it with water, close it. Then in a few days open the hole again in a different location and have a swimming pool?

The description mentions a person stuck inside trying to get out, but does not say anything about using the hole to store/move things.

Quote from JamesGames >>

Each time the hole is opened does it always open to the same space? This would mean that it could be used to transport objects. For example, can I open the Portable Hole, fill it with water, close it. Then in a few days open the hole again in a different location and have a swimming pool?

The description mentions a person stuck inside trying to get out, but does not say anything about using the hole to store/move things.

Quote from JamesGames >>

Each time the hole is opened does it always open to the same space? This would mean that it could be used to transport objects. For example, can I open the Portable Hole, fill it with water, close it. Then in a few days open the hole again in a different location and have a swimming pool?

 I think that’s pretty much academic, those things are basically Looney Toons devices! I got one from a treasure horde at low level because were inexperienced and my DM thought it was just a different kind of bag of holding (basically how I use it). Now the power gamer wants me to use it as an unlimited Passwall 🙄

Quote from Chalm >>

In Dragon Heist, my players used a portable hole to clear out the 500,000 go from the vault, stuffed in a pocket, and walked out.

 Yup. Pretty much.

lol, funny you should say that. Manshoon only had 3 skeletons come clawing their way out of his portable hole in a tavern full of suddenly terrified patrons. 

Don’t worry he was just trying to test the character to see if he was suitable for an important errand. Of course he felt the orc fighter demolished them too quickly for him to get an accurate read so he pulled out a magic jar with an ogre and “clumsily” dropped it. The Beholder illusion card, that was just him being a dick.

Quote from vonSeightlur >>

Quote from JamesGames >>

...can I open the Portable Hole, fill it with water, close it. Then in a few days open the hole again in a different location and have a swimming pool?

Yup! It's unclear whether an empty Portable Hole always opens to the same space, but according to the description it does always open to the same space if it contains something:

Folding the cloth closes the hole, and any creatures or objects within remain in the extradimensional space.

Have fun filling up your new pool. Just make sure you don't suck up a crocodile in the process, because it might beat that STR check and pop out at an inopportune moment!

Quote from Caden_brownfield >>

Roughly how many skeletons could someone fit inside this thing

I've been thinking of an alternative effect of this item. It's always connected to the same extradimentional space but works in the following manner:

1. If the surface this cloth is covering has 10 feet or more of material under or behind it, the item functions at RAW.

2. If the surface this cloth is covering has less than 10 feet of material under or behind it (examples are walls between adjoining rooms, the roof of a building,,etc) then it provides access between the two areas (plus if there is anything inside the interdimentional space , it becomes affected by local gravity and falls into the area per standard gravity effects).

Thoughts?

A portable hole full of warforged, (who don't need to breathe), would make a fun surprise encounter.

How do sense work between planes? I'm thinking sound wouldn't travel either way. I would let sight out, but not in. Any thoughts from anyone? 

Quote from Theran_Baggins >>

WARNING: Math

So, I get that to some calculating carrying capacity by area makes more sense than weight, but, due to that most items only get a weight and don't get any dimensions for area, I was wondering if calculating for a weight capacity for the Portable hole via ratios would be a "fair" within the rules of the game. What I mean is...

Handy haversack (small pouch): 20 lb, 2 ft^3 / Handy haversack (large pouch): 80 lb, 8 ft^3 / Bag of holding: 500 lb, 64 ft^3 / Portable hole: ??? lb, (approximately) 245 ft^3

Handy haversack (small and large pouches)= 10:1 ratio (lb:ft^3) / Bag of holding= 7.8125:1 ratio / Portable hole= ???:1 ratio

The bag of holding's weight capacity (in ratio form) is 78.125% of that of the haversack, so would it be fair to say that the Portable hole's weight (via ratio) is 78.125% that of the bag of holding? Which is roughly 6.1035 (ratio) or 1495.3575 lbs (actual).

I get this is a weird question, and I'm sure using exponential functions would give a more accurate number, but would the place holder of a rounded 1500 lb be a "fair" weight capacity for the Portable hole?

 

 The accurate answer is 'next to nothing' regardless of contents because that's what the text of the item description says. If you want to put a cap on it, that's on you, but by RAW, you could fill it with neutron star material and carry it around like a napkin. 

So, this should really be called a Portable Pit.  You cannot make holes through walls with it.

Quote from Gehennaheretic >>

Quote from Theran_Baggins >>

WARNING: Math

So, I get that to some calculating carrying capacity by area makes more sense than weight, but, due to that most items only get a weight and don't get any dimensions for area, I was wondering if calculating for a weight capacity for the Portable hole via ratios would be a "fair" within the rules of the game. What I mean is...

Handy haversack (small pouch): 20 lb, 2 ft^3 / Handy haversack (large pouch): 80 lb, 8 ft^3 / Bag of holding: 500 lb, 64 ft^3 / Portable hole: ??? lb, (approximately) 245 ft^3

Handy haversack (small and large pouches)= 10:1 ratio (lb:ft^3) / Bag of holding= 7.8125:1 ratio / Portable hole= ???:1 ratio

The bag of holding's weight capacity (in ratio form) is 78.125% of that of the haversack, so would it be fair to say that the Portable hole's weight (via ratio) is 78.125% that of the bag of holding? Which is roughly 6.1035 (ratio) or 1495.3575 lbs (actual).

I get this is a weird question, and I'm sure using exponential functions would give a more accurate number, but would the place holder of a rounded 1500 lb be a "fair" weight capacity for the Portable hole?

 

 The accurate answer is 'next to nothing' regardless of contents because that's what the text of the item description says. If you want to put a cap on it, that's on you, but by RAW, you could fill it with neutron star material and carry it around like a napkin. 

 I think you answered the wrong question, but in the right way.  The question was about making a ruling on the weight capacity of a portable hole, similar to the weight capacity of the handy haversack or bag of holding.  But the answer is still basically "read the text."

If you look up to my math on how many gold coins could be stored in a portable hole, I calculated that even somewhat loosely packed you could store 13,626,481 gold coins in a portable hole.  If you calculate the weight of that, it's 272,529.6 lbs.  So just applying an arbitrary weight limit of 1500lbs significantly handicaps the item (effectively making the most one could store in it 75,000 gold pieces).

It also depends on what you put into it.  There was a suggestion above to make it a portable pool.  If you filled this 6 foot diameter, 10 foot cylinder with water, that would take just shy of 2,114 gallons of water.  Assuming 8.34 pounds per gallon of water at standard pressure and temperature, that's over 17,630 pounds.

So no, if you arbitrarily capped this at 1500lbs, I don't think that would be fair, and if I were your player I'd be pretty upset about it.

So this item has a different definition of place: using it to summon the hole. Therefore, can you PUT it in a bag of holding or handy haversack without PLACING it and carry it around that way? Because at that point the portal isn't open, so I don't really see a conflict (whereas the other two are sort of always open). If so, what happens if something gets out?

Quote from Joesaurus >>

So this item has a different definition of place: using it to summon the hole. Therefore, can you PUT it in a bag of holding or handy haversack without PLACING it and carry it around that way? Because at that point the portal isn't open, so I don't really see a conflict (whereas the other two are sort of always open). If so, what happens if something gets out?

Placing a portable hole inside an extradimensional space created by a bag of holding, handy haversack, or similar item instantly destroys both items and opens a gate to the Astral Plane. The gate originates where the one item was placed inside the other. Any creature within 10 feet of the gate is sucked through it and deposited in a random location on the Astral Plane. The gate then closes. The gate is one-way only and can’t be reopened.

This is my take on it, and I think it is probably also the generally-accepted interpretation: it doesn't say anywhere in there that the hole has to be open in that paragraph.  The portable hole is a portable hole whether open or closed, and placing it into a bag of holding or handy haversack in either form would create a portal to the astral sea.  Not to mention, the portable hole is 6ft across so it won't fit through the mouth of either container in its open form, anyway. 

The semantics of the word "place" is also a weak argument, in my opinion.  I think here it is used in the general English sense: to put in a location.  You unfold it and lay it out on a flat surface and then the hole opens.  You can still place it folded and nothing happens--unless that location happens to be in another extradimensional space.  The portable hole isn't the 6x10ft cylinder, it is the piece of fabric.

You or your DM are free to rule however they want, but the caution wouldn't make much sense if it's to be interpreted as you suggest.  It also seems you overestimate the space inside of a bag of holding; an average-sized human would barely fit, given that the space within is only 2ft in diameter and 4ft deep.  The portable hole cannot be laid flat within, since it is 6ft in diameter and there is no adequately-sized flat surface within.

What would happen if a Beholder was pushed into a portable hole? Assuming it's antimagic cone was facing directly away from the hole, it could be argued that once the Beholder entered, its cone would then affect the hole turning it into a mundane piece of cloth destroying anything inside i.e. the Beholder itself, thereby ending the effect of the antimagic cone returning the cloth to it's portable holiness.

That's an interesting question, and again one that I think falls to your DM to describe. But if I were your DM...

First, a beholder is a large aberration, meaning it occupies a 10ft x 10ft x 10ft cube.  The hole is only 6ft across, but this will be solved if you manage to get an Enlarge/Reduce spell off on it and it fails its CON save.

Okay, so you have a bite-sized beholder now.  Let's say you are able to get it into a portable hole, either with a pushing attack from a battlemaster, a telekinetic shove ability from the telekinetic feat, or the telekinesis spell.  The beholder's main eye anti-magic cone may be active or inactive (as decided by the beholder at the beginning of its turn). 

• If it's inactive, then nothing happens, you shove the monster in the [/magicitem] hole and then on its turn it uses its fly speed to get back out.
• If it's active, then there are several cases.
  • Eye-first: You suggested it, and I'm confirming it, the portable hole becomes a mundane circular silk cloth while in the antimagic cone. in this case you telekinesis it into the hole, which must be on flat ground, meaning it will slam into the ground.  There's no damage listed in the spell for such a maneuver but your DM may grant some bludgeoning damage for it, in line with appropriate fall damage.  That's not the point of this discussion though.
  • Butt-first: Beholder anatomy not withstanding, shoving it into the hole butt first (so that the main eye is the last thing to enter the hole) could have some interesting effects.  The beholder is immediately shunted into the extradimensional space, and I'd rule that while it's in the eye cone, the portal back to the material plane would be deactivated.  This means that the hole would turn back into silk fabric, even though it's properly placed.  However, at the beginning of its turn, it could decide to deactivate the eye-cone and the portal would reactivate as long as the silk fabric is still placed in the appropriate orientation.  If you close it up before that, then you've trapped the beholder in the hole.
  • Partway through: Any orientation that doesn't fit into either of the first two will have the eye cone overlapping the hole while the beholder is partway through.  This will cause the hole to become deactivated while the beholder is halfway into the extradimensional space.  This is where things really get interesting and your DM will have to decide how that resolves.  Does the eye cone deactivating the hole cause the beholder to sever in half, the portion within the extradimensional space cleft from the main body?  Does the extradimensional space just get dispelled and leave the beholder half-in-half-out of the ground?  Does it just do nothing?  That is your DM's call.  I lean toward the first case, and I would award pretty major force damage to the beholder as a result, depending on the portion in the hole at the time.

But let's say we get the beholder in the extradimensional space and close the hole.  Now what?  There's rules for that in the item's description.  The beholder has to make a DC10 strength check, and appears within 5ft of the hole on a success.  Given its +0 STR modifier, that's a 55% chance. It's not a sure thing but very likely they'll get out in a turn or two (unless it's hexed or something; that would be a cool use of a first level spell).

However, the whole premise of the portable hole destroying everything within is inherently flawed, at least insofar as I understand it.  The portable hole is the cloth, not the extradimensional space.  The extradimensional space remains; just the portal is closed. So even if the beholder antimagicked away the portal, the space it was in would remain.  

However, if you wanted to end the encounter using a portable hole at the expense of a rare and uncommon magic item, you could:

1. Beholder takes its turn, antimagic cone is active.
2. Any character unfolds and places the hole.
3. Artificer (or similar caster) reduces the beholder. It does have a +4 to its saving throw but assuming at least a 9th-level caster, should be a saving throw of 17 so there's still a 12 in 20 chance it fails.  Good odds though.
4. Sorcerer (or similar caster) casts Telekinesis.  It's a +0 STR check contesting your +5 spellcasting ability check, so you have good odds to win.  You shove the now-medium beholder into the hole, somehow managing to get it in butt-first.  The eye cone shuts off the portal, rendering the portable hole inert. 
5. Any character folds up the hole and places it beside an open bag of holding.
6. Any character with the mage hand cantrip shoves the hole into the bag and everything within 10ft and in both extradimensional spaces is shunted to a random location in the astral sea. 

The beholder can't get back and combat is over.  It's possible it will come back eventually and you better believe it's gonna hold a grudge.  But combat should be over at that point because that'll take a while, since a beholder has nothing in its stat block to return quickly.

if you do some reseach youll find that putting a bag of holding inside one would destroy both

Quote from Bananakid35 >>

if you do some reseach youll find that putting a bag of holding inside one would destroy both

 

 Is that at me for the above comment?  I know, that's the point of it.