diff --git a/packages/desktop-client/src/components/formula/codeMirror-excelLanguage.tsx b/packages/desktop-client/src/components/formula/codeMirror-excelLanguage.tsx
index 126433dcdc..88afe02cb8 100644
--- a/packages/desktop-client/src/components/formula/codeMirror-excelLanguage.tsx
+++ b/packages/desktop-client/src/components/formula/codeMirror-excelLanguage.tsx
@@ -148,6 +148,7 @@ const LOGICAL_FUNCTIONS = new Set([
 
 const TEXT_FUNCTIONS = new Set([
   'TEXT',
+  'FIXED',
   'CONCATENATE',
   'LEFT',
   'RIGHT',
diff --git a/packages/desktop-client/src/components/formula/queryModeFunctions.ts b/packages/desktop-client/src/components/formula/queryModeFunctions.ts
index 2fba45bbdf..861bbfd522 100644
--- a/packages/desktop-client/src/components/formula/queryModeFunctions.ts
+++ b/packages/desktop-client/src/components/formula/queryModeFunctions.ts
@@ -511,6 +511,14 @@ export const queryModeFunctions: Record<string, FunctionDef> = {
       { name: 'format', description: 'Format' },
     ],
   },
+  FIXED: {
+    name: 'FIXED',
+    description: t('Formats a number to a fixed amount of decimal places.'),
+    parameters: [
+      { name: 'number', description: 'Number' },
+      { name: 'decimals', description: 'Decimals' },
+    ],
+  },
   REPT: {
     name: 'REPT',
     description: t('Repeats text specified number of times.'),
diff --git a/packages/desktop-client/src/components/formula/transactionModeFunctions.ts b/packages/desktop-client/src/components/formula/transactionModeFunctions.ts
index 01ae0df11a..74466ccfde 100644
--- a/packages/desktop-client/src/components/formula/transactionModeFunctions.ts
+++ b/packages/desktop-client/src/components/formula/transactionModeFunctions.ts
@@ -122,6 +122,14 @@ export const transactionModeFunctions: Record<string, FunctionDef> = {
       { name: 'format', description: 'Format' },
     ],
   },
+  FIXED: {
+    name: 'FIXED',
+    description: t('Formats a number to a fixed amount of decimal places.'),
+    parameters: [
+      { name: 'number', description: 'Number' },
+      { name: 'decimals', description: 'Decimals' },
+    ],
+  },
   REPT: {
     name: 'REPT',
     description: t('Repeats text specified number of times.'),
diff --git a/packages/desktop-client/src/hooks/useFormulaExecution.ts b/packages/desktop-client/src/hooks/useFormulaExecution.ts
index 4d47190a26..cd76a0567c 100644
--- a/packages/desktop-client/src/hooks/useFormulaExecution.ts
+++ b/packages/desktop-client/src/hooks/useFormulaExecution.ts
@@ -1,5 +1,7 @@
 import { useEffect, useState } from 'react';
 
+import { HyperFormula } from 'hyperformula';
+
 import { send } from 'loot-core/platform/client/fetch';
 import * as monthUtils from 'loot-core/shared/months';
 import { q, type Query } from 'loot-core/shared/query';
@@ -40,7 +42,6 @@ export function useFormulaExecution(
     let cancelled = false;
 
     async function executeFormula() {
-      const { HyperFormula } = await import('hyperformula');
       let hfInstance: ReturnType<typeof HyperFormula.buildEmpty> | null = null;
 
       if (!formula || !formula.startsWith('=')) {
@@ -118,6 +119,7 @@ export function useFormulaExecution(
         hfInstance = HyperFormula.buildEmpty({
           licenseKey: 'gpl-v3',
           localeLang: typeof locale === 'string' ? locale : 'en-US',
+          language: 'enUS',
         });
 
         // Add a sheet and set the formula in cell A1
diff --git a/packages/loot-core/src/server/rules/action.ts b/packages/loot-core/src/server/rules/action.ts
index fb1ba58f1c..242ef1595c 100644
--- a/packages/loot-core/src/server/rules/action.ts
+++ b/packages/loot-core/src/server/rules/action.ts
@@ -2,6 +2,7 @@
 import * as dateFns from 'date-fns';
 import * as Handlebars from 'handlebars';
 import { HyperFormula } from 'hyperformula';
+import enUS from 'hyperformula/i18n/languages/enUS';
 
 import { amountToInteger } from 'loot-core/shared/util';
 
@@ -10,9 +11,18 @@ import { currentDay, format, parseDate } from '../../shared/months';
 import { FIELD_TYPES } from '../../shared/rules';
 import { type TransactionForRules } from '../transactions/transaction-rules';
 
-import { CustomFunctionsPlugin } from './customFunctions';
+import {
+  CustomFunctionsPlugin,
+  customFunctionsTranslations,
+} from './customFunctions';
 import { assert } from './rule-utils';
 
+HyperFormula.registerLanguage('enUS', enUS);
+HyperFormula.registerFunctionPlugin(
+  CustomFunctionsPlugin,
+  customFunctionsTranslations,
+);
+
 const ACTION_OPS = [
   'set',
   'set-split-amount',
@@ -258,10 +268,9 @@ export class Action {
     }
 
     try {
-      HyperFormula.registerFunctionPlugin(CustomFunctionsPlugin);
-
       hfInstance = HyperFormula.buildEmpty({
         licenseKey: 'gpl-v3',
+        language: 'enUS',
       });
 
       const sheetName = hfInstance.addSheet('Sheet1');
diff --git a/packages/loot-core/src/server/rules/customFunctions.ts b/packages/loot-core/src/server/rules/customFunctions.ts
index f8af1aeb2d..bebd3a9233 100644
--- a/packages/loot-core/src/server/rules/customFunctions.ts
+++ b/packages/loot-core/src/server/rules/customFunctions.ts
@@ -15,6 +15,17 @@ export class CustomFunctionsPlugin extends FunctionPlugin {
       },
     );
   }
+
+  fixed(ast: ProcedureAst, state: InterpreterState) {
+    return this.runFunction(
+      ast.args,
+      state,
+      this.metadata('FIXED'),
+      (number: number, decimals: number = 0) => {
+        return Number(number).toFixed(decimals);
+      },
+    );
+  }
 }
 
 CustomFunctionsPlugin.implementedFunctions = {
@@ -29,4 +40,22 @@ CustomFunctionsPlugin.implementedFunctions = {
       },
     ],
   },
+  FIXED: {
+    method: 'fixed',
+    parameters: [
+      { argumentType: FunctionArgumentType.NUMBER },
+      {
+        argumentType: FunctionArgumentType.NUMBER,
+        optionalArg: true,
+        defaultValue: 0,
+      },
+    ],
+  },
+};
+
+export const customFunctionsTranslations = {
+  enUS: {
+    INTEGER_TO_AMOUNT: 'INTEGER_TO_AMOUNT',
+    FIXED: 'FIXED',
+  },
 };
diff --git a/upcoming-release-notes/6645.md b/upcoming-release-notes/6645.md
new file mode 100644
index 0000000000..f046886423
--- /dev/null
+++ b/upcoming-release-notes/6645.md
@@ -0,0 +1,6 @@
+---
+category: Enhancements
+authors: [matt-fidd]
+---
+
+Add FIXED to EXCEL functions