diff --git a/src/form.ts b/src/form.ts
index 7af93a90..314bf5bc 100644
--- a/src/form.ts
+++ b/src/form.ts
@@ -284,7 +284,7 @@ export function createHeadlessForm(
   const updatedSchema = calculateFinalSchema({
     schema,
     values: initialValues,
-    options: options.legacyOptions,
+    options,
   })
 
   const fields = buildFields({ schema: updatedSchema, originalSchema: schema, strictInputType })
@@ -301,7 +301,7 @@ export function createHeadlessForm(
       const updatedSchema = calculateFinalSchema({
         schema,
         values: value,
-        options: options.legacyOptions,
+        options,
       })
 
       const result = validate(value, updatedSchema, options.legacyOptions)
diff --git a/src/mutations.ts b/src/mutations.ts
index 5c66ed2a..d0925e55 100644
--- a/src/mutations.ts
+++ b/src/mutations.ts
@@ -1,4 +1,5 @@
 import type { Field } from './field/type'
+import type { CreateHeadlessFormOptions } from './form'
 import type { JsfObjectSchema, JsfSchema, JsonLogicContext, NonBooleanJsfSchema, ObjectValue, SchemaValue } from './types'
 import type { LegacyOptions } from './validation/schema'
 import { buildFieldSchema } from './field/schema'
@@ -24,18 +25,19 @@ export function calculateFinalSchema({
 }: {
   schema: JsfObjectSchema
   values: SchemaValue
-  options?: LegacyOptions
+  options?: CreateHeadlessFormOptions
 }): JsfObjectSchema {
   const jsonLogicContext = schema['x-jsf-logic'] ? getJsonLogicContextFromSchema(schema['x-jsf-logic'], values) : undefined
   const schemaCopy = safeDeepClone(schema)
+  const { legacyOptions, customJsonLogicOps } = options
 
-  applySchemaRules(schemaCopy, values, options, jsonLogicContext)
+  applySchemaRules(schemaCopy, values, legacyOptions, jsonLogicContext)
 
   if (jsonLogicContext?.schema.computedValues) {
-    applyComputedAttrsToSchema(schemaCopy, jsonLogicContext.schema.computedValues, values)
+    applyComputedAttrsToSchema(schemaCopy, jsonLogicContext.schema.computedValues, values, customJsonLogicOps)
     // If we had computed values applied to the schema,
     // we need to re-apply the schema rules to update the fields
-    applySchemaRules(schemaCopy, values, options, jsonLogicContext)
+    applySchemaRules(schemaCopy, values, legacyOptions, jsonLogicContext)
   }
 
   return schemaCopy
diff --git a/src/validation/json-logic.ts b/src/validation/json-logic.ts
index 4d5da80f..db4ba6fd 100644
--- a/src/validation/json-logic.ts
+++ b/src/validation/json-logic.ts
@@ -1,5 +1,6 @@
 import type { RulesLogic } from 'json-logic-js'
 import type { ValidationError, ValidationErrorPath } from '../errors'
+import type { CreateHeadlessFormOptions } from '../form'
 import type { JsfObjectSchema, JsfSchema, JsonLogicContext, JsonLogicRules, JsonLogicSchema, NonBooleanJsfSchema, ObjectValue, SchemaValue } from '../types'
 import jsonLogic from 'json-logic-js'
 
@@ -128,18 +129,23 @@ export function computePropertyValues(
  * @param schema - The schema to apply computed attributes to
  * @param computedValuesDefinition - The computed values to apply
  * @param values - The current form values
+ * @param customJsonLogicOps - The custom JSON Logic operations to apply
  * @returns The schema with computed attributes applied
  */
-export function applyComputedAttrsToSchema(schema: JsfObjectSchema, computedValuesDefinition: JsonLogicRules['computedValues'], values: SchemaValue): JsfObjectSchema {
+export function applyComputedAttrsToSchema(schema: JsfObjectSchema, computedValuesDefinition: JsonLogicRules['computedValues'], values: SchemaValue, customJsonLogicOps: CreateHeadlessFormOptions['customJsonLogicOps'] = {}): JsfObjectSchema {
   if (computedValuesDefinition) {
     const computedValues: Record<string, any> = {}
 
+    addCustomJsonLogicOperations(customJsonLogicOps)
+
     Object.entries(computedValuesDefinition).forEach(([name, definition]) => {
       const computedValue = computePropertyValues(name, definition.rule, values)
       computedValues[name] = computedValue
     })
 
     cycleThroughPropertiesAndApplyValues(schema, computedValues)
+
+    removeCustomJsonLogicOperations(customJsonLogicOps)
   }
 
   return schema
diff --git a/test/validation/json-logic-v0.test.js b/test/validation/json-logic-v0.test.js
index 727e0916..2c7f6bc8 100644
--- a/test/validation/json-logic-v0.test.js
+++ b/test/validation/json-logic-v0.test.js
@@ -15,6 +15,7 @@ import {
   schemaWithComputedAttributeThatDoesntExist,
   schemaWithComputedAttributeThatDoesntExistDescription,
   schemaWithComputedAttributeThatDoesntExistTitle,
+  schemaWithCustomComputedValueFunction,
   schemaWithCustomValidationFunction,
   schemaWithDeepVarThatDoesNotExist,
   schemaWithDeepVarThatDoesNotExistOnFieldset,
@@ -475,10 +476,18 @@ describe('jsonLogic: cross-values validations', () => {
 
     it('validation on custom functions', () => {
       const actionThatWillThrow = () => {
-        createHeadlessForm(schemaWithCustomValidationFunction, { strictInputType: false, customJsonLogicOps: { is_hello: 'not a funcion' } })
+        createHeadlessForm(schemaWithCustomValidationFunction, { strictInputType: false, customJsonLogicOps: { is_hello: 'not a function' } })
       }
 
       expect(actionThatWillThrow).toThrow('Custom JSON Logic operator \'is_hello\' must be a function, but received type \'string\'.')
     })
+
+    it('applies custom functions when initial values require them', () => {
+      const actionThatWillThrow = () => {
+        createHeadlessForm(schemaWithCustomComputedValueFunction, { strictInputType: false, customJsonLogicOps: { is_hello: a => a === 'hello world!' } })
+      }
+
+      expect(actionThatWillThrow).not.toThrow()
+    })
   })
 })
diff --git a/test/validation/json-logic.fixtures.js b/test/validation/json-logic.fixtures.js
index 15a70616..2ccd5c89 100644
--- a/test/validation/json-logic.fixtures.js
+++ b/test/validation/json-logic.fixtures.js
@@ -763,3 +763,33 @@ export const schemaWithCustomValidationFunction = {
     },
   },
 }
+
+export const schemaWithCustomComputedValueFunction = {
+  'properties': {
+    field_a: {
+      type: 'string',
+    },
+    field_b: {
+      'type': 'string',
+      'title': 'Field with computed description',
+      'x-jsf-logic-computedAttrs': {
+        description: 'Computed value is {{custom_function_result}}',
+      },
+    },
+  },
+  'x-jsf-logic': {
+    computedValues: {
+      custom_function_result: {
+        rule: {
+          if: [
+            {
+              is_hello: { var: 'field_a' },
+            },
+            'value1',
+            'value2',
+          ],
+        },
+      },
+    },
+  },
+}