About Us

Umamusume Affinity Calculator is a fan-built tool made for trainers who want faster, clearer planning around inheritance compatibility in Umamusume: Pretty Derby. You pick a Main Character, choose parents (Legacy 1 & Legacy 2), optionally add grandparents, and the calculator shows a live Total Affinity result—so you can iterate quickly instead of guessing.

In-game compatibility can feel opaque, and outcomes can be influenced by a lot of details. Our goal is simple: provide a clean, mobile-friendly interface that helps you explore combinations and understand how compatibility tiers (like ○ vs ◎) map to your planning decisions.

What we focus on

• Clarity. The UI is built around the exact decisions you make: Main Char → parents → grandparents.
• Speed. Results update as you change selections, with simple actions like Reset / Reset All.
• Practical guidance. We explain what the tool assumes (trait groups, relationship points, basic thresholds) so expectations stay realistic.
• Privacy by default. No accounts required; we aim to keep data collection minimal and transparent.

A friendly disclaimer

This is an unofficial fan project. Compatibility mechanics may change, and the calculator is an approximation—not a guarantee of in-game outcomes.

Say hello

Found a bug, want a feature (like better recommendations), or spotted a mismatch? Send it through the contact page. Your feedback helps keep the tool sharp and useful.

Last updated: November 30, 2025