How can I calculate percentage of a number in solidity?

Question

How can I calculate percentage of a number in solidity? say I want to calculate 95% of the number 200.

How should I go about doing that ?

score 0 · Answer 1 · answered Jul 10 '20 at 02:20

0

It is hard to calculate exact number by division in computer.

If just you want to get 95% of 200, 200/100 * 95 is the answer. But if you ask how can i get exact number of result of division, it can't in some number.

answered Jul 10 '20 at 02:20

defender

9
1

3

isn't it (200 * 95) / 100 ? – Adrin Jul 10 '20 at 04:42
MATH :) hint it's the same – pasevin Jul 10 '21 at 09:09
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@pasevin not the same in solidity – Richard Aug 04 '21 at 07:23

@Richard Why do you say so?

function test1() public pure returns(uint) {
    return (200 * 95) / 100;
}

function test2() public pure returns(uint) {
    return 200 / 100 * 95;
}

Will return exactly the same result.

– pasevin Aug 06 '21 at 07:26

Im talking about cases where { return x / 100 * 95; } and x is small enough to bring floating point errors. – Richard Aug 06 '21 at 10:25
1

Good point, thanks for clarifying. – pasevin Aug 07 '21 at 09:05

How can I calculate percentage of a number in solidity?

1 Answers1