How to Calculate Bitcoin Transaction Size


welcome to one minute crypto I'm your

host Carlos and today I want to talk

about the exact formula that goes into

calculating how much you need to pay in

fees on a Bitcoin transaction I've seen

a lot of posts recently celebrating hey

I was able to pay so little in fees in

my transaction confirmed so quickly but

actually what people don't realize is

that the fee is not dependent on the

number of bitcoins you send it's

actually dependent on the size of the

Bitcoin transaction and size is not

bitcoins it's the number of input and

outputs that go into the transaction I'm

gonna give you the exact formula so you

can calculate the size of your own

transactions here in this video but

first I want to thank our sponsor

because this episode is proudly

sponsored by Kiki a USB hardware wallet

that plugs into your computer to keep

your cryptocurrency safe this little

guy's stores your private keys directly

on it so even if your computer gets a

virus your funds are still secure check

them out at Keep Calm so like I was

saying the size of a transaction is

based on the number of inputs and

outputs now typically when you're

sending a Bitcoin transaction you're

only going to have one output because

you're sending it to one person either

yourself for a transfer or an exchange

or another person or business but you

actually need a second output you're

typically gonna have two outputs because

you're not sending all of the bitcoins

that are involved in the transaction you

need some as change take for example if

you've got one Bitcoin in an address and

you want to send point zero zero five

you can't just send point zero zero five

and have that be or one output the

transaction needs to have all of the

bitcoins accounted for so you're gonna

have 0.005 going to the destination and

then 0.995 the remaining amount going to

a different destination that you control

that's called the change dress so it's

very very common to have two outputs one

for the person you're paying and one for

yourself as a change address so now we

know there's two outputs how many inputs

are there gonna be

well that just depends on how your

bitcoins are spread out inputs do not

mean source addresses it actually means

source unspent transaction outputs for

you TX OS which means every time you're

paid Bitcoin that's one input so if you

receive five payments you've got those

in five different u TX OS if you want to

go send that all at once your

transaction has five inputs and that's

gonna make a large transaction which

costs more in fees so here's the exact

formula it's the number of inputs times

a hundred and forty eight bytes now

typically that's gonna be one or two

inputs but if you have received a lot of

Bitcoin at a lot of different times

it'll be more and then you add the

number of outputs times 34 bytes

now this is the bulk of the transaction

the number of inputs number of outputs

here being multiplied by these numbers

makes up the huge majority of the size

after you've done that you add 10 more

bytes and then plus or minus the number

of inputs in bytes so if you've got two

inputs and two outputs that's 2 times

148 plus 2 times 34 plus 10 and then

maybe you're gonna add two more for the

two extra inputs that's because some

input addresses are a little bit shorter

than others and so you do have that

slight variance but basically the number

of bytes is hugely based on the number

of inputs you can see that multiplier

148 is much bigger than the 34

multiplier so the best way to keep your

fees down is to limit the number of

inputs that you're using in the

transaction if you have any questions

feel free to post in the comments below

the video I'd love to help you out in

any way I can

I'm Chronos thanks for watching