How many USDT transfers fit in one Tron energy order?

Short answer

65,000 covers one USDT transfer to someone who already holds USDT. 131,000 covers one transfer to someone whose balance is zero, or two transfers to people who already hold it. 4,000,000, the largest order, covers 62 of the first kind or 30 of the second. On a 15-minute or one-hour rental, that is the whole order. On a longer one, the same energy can refill and be spent again.

Buying a million "so you do not run out"

An order is a pile of energy on your address until the clock runs out. Each USDT transfer takes a bite. At the end of the rental, what you did not spend leaves with the delegation. It is not saved for next week. A 4,000,000 order for a single payment is a pile you will not touch.

For one send, buy one bite. 65,000 if they already have USDT, 131,000 if they do not. For a busy hour from one address, add the bites and buy a single order that covers the sum, somewhere between 65,000 and 4,000,000. If the hour is quiet and tomorrow looks like today, a one-day rental of a smaller pile is often cheaper than a huge pile for one hour, because the pile refills. How long the rental should last is that decision. The size is this one.

Recipients do not average. One person with an empty USDT balance and one person who already holds it are not "about 100,000 each." They add. The empty one is the expensive bite, and forgetting that is how a pile that looked generous runs out on payout number four.

Count against 64,285 and 130,285, not against the round order

Each transfer that completes consumes 64,285 energy if the recipient's USDT slot exists, and 130,285 if it does not. The round orders are 715 higher. That 715 is slack on a single transfer. It is not most of another one. Where those two consumption figures come from is the contract call, measured, not a pack size a seller invented.

One pass, ignoring refill:

62 times 64,285 is 3,985,670, so 4,000,000 leaves 14,330, short of another transfer. 30 times 130,285 is 3,908,550, so 4,000,000 leaves 91,450, also short. One empty slot plus one existing slot is 130,285 + 64,285 = 194,570. If you want about 715 of slack on that pair, order 195,000, not 131,000.

Refill during the rental is the limit times the seconds, divided by 86,400. On 64,285 that is about 669 energy in 15 minutes and about 2,678 in an hour. On 130,285, about 1,357 and about 5,428. None of those is another USDT transfer, so a 15-minute or one-hour order stops at the table. A one-day rental of the same limit can support a second pass later, after the first has recovered. It cannot support two passes in the same minute. Three days keep that daily rate going. They do not make the limit three times larger at the start.

If the address already holds energy, subtract it before you pick the order. The order you send still has to sit between 65,000 and 4,000,000. If no seller can approach the size in one fill, the order is refused rather than silently split. And if a seller answers with a larger pack than you typed, that extra is real energy, subject to the rule that keeps a padded pack from costing more than burning.