Use this script to calculate the probability of generating duplicate hashes given the number of possible values and the number of values generated.

calculate-hash-collision-probability.js

//   MIT License
//   
//   Copyright (c) 2021 Charles Hill
//   
//   Permission is hereby granted, free of charge, to any person obtaining a copy
//   of this software and associated documentation files (the "Software"), to deal
//   in the Software without restriction, including without limitation the rights
//   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//   copies of the Software, and to permit persons to whom the Software is
//   furnished to do so, subject to the following conditions:
//   
//   The above copyright notice and this permission notice shall be included in all
//   copies or substantial portions of the Software.
//   
//   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
//   SOFTWARE.
//   
//   For a human-friendly explanation of this license:
//   https://tldrlegal.com/license/mit-license
//   
//   If you have questions technical or otherwise, find my contact details here:
//   https://degreesofzero.com/
//   
//   Run via nodejs:
//   node ./calculate-hash-collision-probability.js
//   
//   Or run in the browser by copy/pasting to console.
//   
//   For more details:
//   https://preshing.com/20110504/hash-collision-probabilities/
//   
const k = (10**6);// Number of randomly generated values.
const n = 2048**5;// Total possible values.
const chance = 1 - Math.exp((-1 * k * (k - 1)) / (2 * n));
console.log({
	k,
	n,
	chance,
	chancePercent: (Math.round(chance * 1000000) / 10000) + ' %',
});