If you are building units in Fire Emblem Heroes, understanding IVs (also called Assets and Flaws) is one of the fastest ways to improve your team. Use the calculator below to estimate how a hero’s level 40 stats change based on trait choices.
What is an IV in Fire Emblem Heroes?
In FEH, each hero can have small stat differences called individual values (IVs). One stat usually becomes an Asset (higher), while another becomes a Flaw (lower). This can change breakpoints for doubles, one-shots, or survival in high-end modes.
Why an IV Calculator Helps
- Quickly compare different trait setups before spending Trait Fruits.
- Check whether +Spd or +Atk gives better combat thresholds.
- See the effect of Ascended Assets at a glance.
- Plan arena and Aether Raids builds more efficiently.
How to Use This Calculator
Step 1: Enter Neutral Stats
Use your hero’s known neutral level 40 stats (from in-game or a trusted FEH database).
Step 2: Pick Asset and Flaw
Select the IV spread you want to test. For example, a fast offensive unit may prefer +Spd, while a nuke might prefer +Atk.
Step 3: Add Ascended Asset (Optional)
If your unit has an Ascended Asset, choose it to see both stat boosts together.
Step 4: Tick Merge Fix
If the unit is merged at least once, check the box so the flaw penalty is removed in the result.
Practical Build Advice
Offensive Units
- +Atk for raw damage and one-shot potential.
- +Spd if your unit relies on doubling or damage reduction checks.
Tanks and Supports
- +Def or +Res depending on threat profile.
- +HP can matter for skills with HP thresholds and support effects.
FAQ
Can Asset and Flaw be the same stat?
No. This tool prevents that combination so your results stay valid.
Is this exact for every single hero?
It is a fast planning model designed to be practical and easy. Some heroes may differ by growth pattern details, but for everyday build decisions this calculator is very useful.
Should I always remove a flaw with merges?
Usually yes, especially if the flaw hits a key stat. Merging to +1 often improves performance immediately by eliminating that penalty.