diff --git a/stores/calculation/index.ts b/stores/calculation/index.ts
index 5e3dd83..96525b0 100644
--- a/stores/calculation/index.ts
+++ b/stores/calculation/index.ts
@@ -2,16 +2,19 @@
 import RootStore from 'stores/root';
 import OptionsStore from './options';
 import StatusStore from './statuses';
+import ValidationStore from './validation';
 import ValuesStore from './values';
 
 export default class CalculationStore {
   $values: ValuesStore;
   $status: StatusStore;
   $options: OptionsStore;
+  $validation: ValidationStore;
 
   constructor(rootStore: RootStore) {
     this.$values = new ValuesStore(rootStore);
     this.$status = new StatusStore(rootStore);
     this.$options = new OptionsStore(rootStore);
+    this.$validation = new ValidationStore(rootStore);
   }
 }
diff --git a/stores/calculation/validation/index.ts b/stores/calculation/validation/index.ts
new file mode 100644
index 0000000..14c0381
--- /dev/null
+++ b/stores/calculation/validation/index.ts
@@ -0,0 +1,50 @@
+/* eslint-disable import/no-cycle */
+/* eslint-disable implicit-arrow-linebreak */
+/* eslint-disable object-curly-newline */
+import type { Elements } from 'Components/Calculation/config/map';
+import { makeAutoObservable, observable } from 'mobx';
+import RootStore from 'stores/root';
+import type { Error, Messages } from './types';
+
+export default class ValidationStore {
+  root: RootStore;
+  #messages: Partial<Messages> = {};
+
+  constructor(rootStore: RootStore) {
+    makeAutoObservable(this);
+    this.root = rootStore;
+  }
+
+  getValidation(elementName: Elements) {
+    return {
+      isValid: !this.#messages[elementName]?.length,
+      messages: this.#messages[elementName]?.map((x) => x.text),
+    };
+  }
+
+  addError(elementName: Elements, error: Error) {
+    if (!this.#messages[elementName]) this.#messages[elementName] = observable([]);
+
+    const errorIndex = this.#messages[elementName]?.findIndex((x) => x.name === error.name);
+    const hasError = errorIndex !== undefined && errorIndex !== -1;
+
+    if (!hasError) {
+      this.#messages[elementName]?.push(error);
+    } else {
+      this.#messages[elementName]?.splice(errorIndex, 1, error);
+    }
+
+    // TODO: call notification
+
+    return () => this.#removeError(elementName, error.name);
+  }
+
+  #removeError(elementName: Elements, errorName: string) {
+    const messageIndex = this.#messages[elementName]?.findIndex((x) => x.name === errorName);
+    if (messageIndex) this.#messages[elementName]?.splice(messageIndex, 1);
+  }
+
+  clearErrors(elementName: Elements) {
+    this.#messages[elementName]?.clear();
+  }
+}
diff --git a/stores/calculation/validation/types.ts b/stores/calculation/validation/types.ts
new file mode 100644
index 0000000..bffacdd
--- /dev/null
+++ b/stores/calculation/validation/types.ts
@@ -0,0 +1,5 @@
+import type { Elements } from 'Components/Calculation/config/map';
+import type { IObservableArray } from 'mobx';
+
+export type Error = { name: string; text: string };
+export type Messages = Record<Elements, IObservableArray<Error>>;