diff --git a/components/Categories.tsx b/components/Categories.tsx
index fe63c2c..87c6698 100644
--- a/components/Categories.tsx
+++ b/components/Categories.tsx
@@ -1,8 +1,8 @@
 import { ChangeEvent } from 'react'
 import { AnimatePresence } from 'framer-motion'
 
-import { CategoryName } from '../utils/types/Category'
-import { PersonList } from '../utils/types/Person'
+import { CategoryName } from '../core/types/Category'
+import { PersonList } from '../core/types/Person'
 
 import { Mode, useModeContext } from '../context/ModeContext'
 import { usePeopleDispatchContext } from '../context/PeopleContext'
diff --git a/components/RelativeCard.tsx b/components/RelativeCard.tsx
index 5af5d44..bda7987 100644
--- a/components/RelativeCard.tsx
+++ b/components/RelativeCard.tsx
@@ -1,7 +1,7 @@
 import Link from 'next/link'
 import { ChangeEvent } from 'react'
 import { usePeopleDispatchContext } from '../context/PeopleContext'
-import { Person } from '../utils/types/Person'
+import { Person } from '../core/types/Person'
 
 interface RelativeCardProps {
   id: string
diff --git a/components/RelativeCardList.tsx b/components/RelativeCardList.tsx
index d84d34c..8e4c4ca 100644
--- a/components/RelativeCardList.tsx
+++ b/components/RelativeCardList.tsx
@@ -1,11 +1,11 @@
 import { AnimatePresence, motion } from 'framer-motion'
 
-import { CategoryName } from '../utils/types/Category'
+import { CategoryName } from '../core/types/Category'
 import { usePeopleDispatchContext } from '../context/PeopleContext'
 import { Mode } from '../context/ModeContext'
 
 import RelativeCard from './RelativeCard'
-import { PersonList } from '../utils/types/Person'
+import { PersonList } from '../core/types/Person'
 
 interface RelativeCardListProps {
   id: string
diff --git a/components/RelativesForm.tsx b/components/RelativesForm.tsx
index 251af9b..98c8019 100644
--- a/components/RelativesForm.tsx
+++ b/components/RelativesForm.tsx
@@ -1,5 +1,5 @@
 import { ChangeEvent, FormEvent } from 'react'
-import { Person, PersonList } from '../utils/types/Person'
+import { Person, PersonList } from '../core/types/Person'
 
 import { usePeopleDispatchContext } from '../context/PeopleContext'
 
diff --git a/components/Results.tsx b/components/Results.tsx
index 0db3444..237cc73 100644
--- a/components/Results.tsx
+++ b/components/Results.tsx
@@ -1,7 +1,7 @@
 import { Dispatch, SetStateAction, useState } from 'react'
 import Fraction from 'fraction.js'
-import { Person, PersonList } from '../utils/types/Person'
-import { CategoryName } from '../utils/types/Category'
+import { Person, PersonList } from '../core/types/Person'
+import { CategoryName } from '../core/types/Category'
 
 import { useModeContext } from '../context/ModeContext'
 import { useMoneyContext } from '../context/MoneyContext'
diff --git a/context/PeopleContext.tsx b/context/PeopleContext.tsx
index e4e3e23..285f8cc 100644
--- a/context/PeopleContext.tsx
+++ b/context/PeopleContext.tsx
@@ -1,6 +1,6 @@
 import { createContext, Dispatch, ReactNode, useContext, useReducer } from 'react'
-import { CategoryName } from '../utils/types/Category'
-import { Person, PersonList } from '../utils/types/Person'
+import { CategoryName } from '../core/types/Category'
+import { Person, PersonList } from '../core/types/Person'
 
 export const PeopleContext = createContext<PersonList | null>(null)
 export const PeopleDispatchContext = createContext<Dispatch<PeopleAction> | null>(null)
diff --git a/utils/graph.ts b/core/graph.ts
similarity index 100%
rename from utils/graph.ts
rename to core/graph.ts
diff --git a/utils/inheritance.ts b/core/inheritance.ts
similarity index 100%
rename from utils/inheritance.ts
rename to core/inheritance.ts
diff --git a/utils/patrimony.ts b/core/patrimony.ts
similarity index 100%
rename from utils/patrimony.ts
rename to core/patrimony.ts
diff --git a/utils/tests/common.ts b/core/tests/common.ts
similarity index 100%
rename from utils/tests/common.ts
rename to core/tests/common.ts
diff --git a/utils/tests/inheritance.test.ts b/core/tests/inheritance.test.ts
similarity index 100%
rename from utils/tests/inheritance.test.ts
rename to core/tests/inheritance.test.ts
diff --git a/utils/tests/patrimony.test.ts b/core/tests/patrimony.test.ts
similarity index 100%
rename from utils/tests/patrimony.test.ts
rename to core/tests/patrimony.test.ts
diff --git a/utils/types/Category.ts b/core/types/Category.ts
similarity index 100%
rename from utils/types/Category.ts
rename to core/types/Category.ts
diff --git a/utils/types/Person.ts b/core/types/Person.ts
similarity index 100%
rename from utils/types/Person.ts
rename to core/types/Person.ts
diff --git a/hooks/useMe.ts b/hooks/useMe.ts
index d74de35..66ac81a 100644
--- a/hooks/useMe.ts
+++ b/hooks/useMe.ts
@@ -1,7 +1,7 @@
 import { useRouter } from 'next/router'
 import { useEffect } from 'react'
 import { usePeopleContext } from '../context/PeopleContext'
-import { Person, PersonList } from '../utils/types/Person'
+import { Person, PersonList } from '../core/types/Person'
 
 export function useMe(id: string): { me: Person | undefined; list: PersonList } {
   const router = useRouter()
diff --git a/pages/api/inheritance.ts b/pages/api/inheritance.ts
index ff9a5ba..f7be1c0 100644
--- a/pages/api/inheritance.ts
+++ b/pages/api/inheritance.ts
@@ -1,5 +1,5 @@
 import { NextApiRequest, NextApiResponse } from 'next'
-import { calculateInheritance } from '../../utils/inheritance'
+import { calculateInheritance } from '../../core/inheritance'
 
 export default function handler(req: NextApiRequest, res: NextApiResponse) {
   if (req.method !== 'POST') return res.status(405).send({ error: 'Method not allowed' })
diff --git a/pages/api/patrimony.ts b/pages/api/patrimony.ts
index e12d46f..eff095e 100644
--- a/pages/api/patrimony.ts
+++ b/pages/api/patrimony.ts
@@ -1,5 +1,5 @@
 import { NextApiRequest, NextApiResponse } from 'next'
-import { calculatePatrimony } from '../../utils/patrimony'
+import { calculatePatrimony } from '../../core/patrimony'
 
 export default function handler(req: NextApiRequest, res: NextApiResponse) {
   if (req.method !== 'POST') return res.status(405).send({ error: 'Method not allowed' })