diff --git a/src/app/alerts/page.tsx b/src/app/alerts/page.tsx
index 10d61ee..0cb4084 100644
--- a/src/app/alerts/page.tsx
+++ b/src/app/alerts/page.tsx
@@ -22,6 +22,7 @@ import {
   type Alert,
 } from "@/lib/backend";
 import { QueryErrorAlert } from "@/components/QueryErrorAlert/QueryErrorAlert";
+import FieldError from "@/components/FieldError/FieldError";
 
 export default function AlertsPage() {
   const toast = useToast();
@@ -142,15 +143,11 @@ export default function AlertsPage() {
           bg="app.inputBg"
           isInvalid={Boolean(apiKeyError)}
           aria-invalid={Boolean(apiKeyError)}
-          aria-describedby="api-key-help"
+          aria-describedby="api-key-error api-key-help"
           _hover={{ borderColor: apiKeyError ? "app.errorFg" : "app.accent" }}
           _focus={{ boxShadow: "none", borderColor: apiKeyError ? "app.errorFg" : "app.accent" }}
         />
-        {apiKeyError && (
-          <Text fontSize="xs" color="app.errorFg" mt={2}>
-            {apiKeyError}
-          </Text>
-        )}
+        <FieldError id="api-key-error" message={apiKeyError} mt={2} />
         <Text id="api-key-help" fontSize="xs" color="app.muted" mt={2}>
           This endpoint requires backend authentication. The key is only kept in this page&apos;s memory — it is never stored or sent anywhere except the backend API.
         </Text>
diff --git a/src/app/farm/[poolId]/PoolDetailClient.tsx b/src/app/farm/[poolId]/PoolDetailClient.tsx
index 7be5552..084fda2 100644
--- a/src/app/farm/[poolId]/PoolDetailClient.tsx
+++ b/src/app/farm/[poolId]/PoolDetailClient.tsx
@@ -1,8 +1,9 @@
 "use client";
 
-import { useEffect, useMemo, useRef, useState } from "react";
+import { useEffect, useId, useMemo, useRef, useState } from "react";
 import NextLink from "next/link";
 import TransactionConfirmModal from "@/components/TransactionConfirmModal/TransactionConfirmModal";
+import FieldError from "@/components/FieldError/FieldError";
 import {
   Alert,
   AlertIcon,
@@ -209,6 +210,11 @@ export default function PoolDetailClient({ poolId }: { poolId: string }) {
 
   const displayAmount = parseFloat(rawAmount);
   const amountValid = Number.isFinite(displayAmount) && displayAmount > 0;
+  const amountError =
+    rawAmount !== "0" && rawAmount !== "" && !amountValid
+      ? "Enter an amount greater than 0."
+      : null;
+  const amountErrorId = useId();
   const isPending = isDepositPending(flow.step);
   const lockPeriodLabel = pool
     ? pool.minLockPeriod >= 86400
@@ -441,6 +447,8 @@ export default function PoolDetailClient({ poolId }: { poolId: string }) {
                   value={rawAmount}
                   onChange={(e) => setRawAmount(e.target.value)}
                   isDisabled={isPending}
+                  isInvalid={Boolean(amountError)}
+                  aria-describedby={amountErrorId}
                   borderRadius="2xl"
                   h="50px"
                   borderColor="app.border"
@@ -449,11 +457,7 @@ export default function PoolDetailClient({ poolId }: { poolId: string }) {
                   _hover={{ borderColor: "app.accent" }}
                   _focus={{ boxShadow: "none", borderColor: "app.accent" }}
                 />
-                {rawAmount !== "0" && rawAmount !== "" && !amountValid && (
-                  <Text fontSize="xs" color="app.errorFg">
-                    Enter an amount greater than 0.
-                  </Text>
-                )}
+                <FieldError id={amountErrorId} message={amountError} />
               </Flex>
 
               {isPending && (
diff --git a/src/app/farm/page.tsx b/src/app/farm/page.tsx
index 201b80e..be8c2b5 100644
--- a/src/app/farm/page.tsx
+++ b/src/app/farm/page.tsx
@@ -6,6 +6,7 @@ import UnlockModal from "@/components/UnlockModal/UnlockModal";
 import BoostModal from "@/components/BoostModal/BoostModal";
 import Breadcrumbs from "@/components/Breadcrumbs/Breadcrumbs";
 import TransactionConfirmModal from "@/components/TransactionConfirmModal/TransactionConfirmModal";
+import FieldError from "@/components/FieldError/FieldError";
 import { EarningRow, MetricColumn } from "@/app/farm/EarningRow";
 import { FarmPoolRow } from "@/app/farm/FarmPoolRow";
 import {
@@ -49,7 +50,7 @@ import {
   useToast,
 } from "@chakra-ui/react";
 import { useOwnConnectButton } from "@/context/OwnConnectButtonContext";
-import { useEffect, useMemo, useState } from "react";
+import { useEffect, useId, useMemo, useState } from "react";
 
 const ACCENT = "#4AE292";
 
@@ -117,6 +118,13 @@ function DepositModal({
     amountValid &&
     typeof availableBalance === "number" &&
     numericAmount > availableBalance;
+  const amountError =
+    !!trimmedAmount && !amountValid
+      ? "Enter a positive amount with no more than 7 decimals."
+      : exceedsBalance
+        ? "Amount exceeds your Horizon XLM balance."
+        : null;
+  const amountErrorId = useId();
   const feePreview = useLockAssetsFeePreview({
     publicKey,
     poolContractId: selectedContractAddress,
@@ -260,6 +268,8 @@ function DepositModal({
                   value={amount}
                   onChange={(event) => setAmount(event.target.value)}
                   isDisabled={isPending}
+                  isInvalid={Boolean(amountError)}
+                  aria-describedby={amountErrorId}
                   borderRadius="2xl"
                   h="50px"
                   borderColor="app.border"
@@ -281,16 +291,7 @@ function DepositModal({
                   {farm.symbol}
                 </Text>
               </Box>
-              {!!trimmedAmount && !amountValid && (
-                <Text fontSize="xs" color="app.errorFg">
-                  Enter a positive amount with no more than 7 decimals.
-                </Text>
-              )}
-              {exceedsBalance && (
-                <Text fontSize="xs" color="app.errorFg">
-                  Amount exceeds your Horizon XLM balance.
-                </Text>
-              )}
+              <FieldError id={amountErrorId} message={amountError} />
             </Flex>
 
             {isPending && (
diff --git a/src/components/FieldError/FieldError.test.tsx b/src/components/FieldError/FieldError.test.tsx
new file mode 100644
index 0000000..49b0d9d
--- /dev/null
+++ b/src/components/FieldError/FieldError.test.tsx
@@ -0,0 +1,51 @@
+import { render, screen } from "@testing-library/react";
+import { ChakraProvider, Input } from "@chakra-ui/react";
+import { describe, expect, it } from "vitest";
+import FieldError from "./FieldError";
+
+function Field({ error }: { error: string | null }) {
+  return (
+    <ChakraProvider>
+      <Input
+        aria-label="Amount"
+        isInvalid={Boolean(error)}
+        aria-describedby="amount-error"
+      />
+      <FieldError id="amount-error" message={error} />
+    </ChakraProvider>
+  );
+}
+
+describe("FieldError", () => {
+  it("keeps a polite live region mounted even when there is no error", () => {
+    const { container } = render(<Field error={null} />);
+
+    const region = container.querySelector("#amount-error");
+    expect(region).not.toBeNull();
+    expect(region?.getAttribute("aria-live")).toBe("polite");
+    expect(region?.getAttribute("aria-atomic")).toBe("true");
+    expect(region?.textContent).toBe("");
+  });
+
+  it("renders the message inside the same region node when an error appears", () => {
+    const { container, rerender } = render(<Field error={null} />);
+    const region = container.querySelector("#amount-error");
+
+    rerender(<Field error="Enter an amount greater than 0." />);
+
+    // Same node, so AT that was already watching it announces the change.
+    expect(container.querySelector("#amount-error")).toBe(region);
+    expect(region?.textContent).toBe("Enter an amount greater than 0.");
+  });
+
+  it("is referenced by the input's accessible description", () => {
+    render(<Field error="Amount exceeds your balance." />);
+
+    const input = screen.getByLabelText("Amount");
+    expect(input.getAttribute("aria-invalid")).toBe("true");
+    const describedBy = input.getAttribute("aria-describedby") ?? "";
+    expect(document.getElementById(describedBy)?.textContent).toBe(
+      "Amount exceeds your balance.",
+    );
+  });
+});
diff --git a/src/components/FieldError/FieldError.tsx b/src/components/FieldError/FieldError.tsx
new file mode 100644
index 0000000..94cdd4f
--- /dev/null
+++ b/src/components/FieldError/FieldError.tsx
@@ -0,0 +1,34 @@
+"use client";
+
+import { Box, Text, type TextProps } from "@chakra-ui/react";
+
+type FieldErrorProps = Omit<TextProps, "id" | "children"> & {
+  /** Referenced by the input's `aria-describedby`. */
+  id: string;
+  /** Validation message; falsy renders an empty (silent) region. */
+  message?: string | null;
+};
+
+/**
+ * Inline form validation error that screen readers announce as it appears
+ * or changes. The aria-live wrapper stays mounted even with no error:
+ * screen readers only announce changes inside a region that already exists,
+ * so mounting the region together with its text (the previous
+ * `{error && <Text>}` pattern) is silently skipped by most AT.
+ *
+ * Polite rather than assertive so validation-as-you-type doesn't cut off
+ * the user's own keystroke echo. Pair with `isInvalid` (Chakra derives
+ * `aria-invalid` from it and ignores a raw `aria-invalid` prop) and
+ * `aria-describedby={id}` on the input so the error is also read on focus.
+ */
+export default function FieldError({ id, message, ...textProps }: FieldErrorProps) {
+  return (
+    <Box id={id} aria-live="polite" aria-atomic="true">
+      {message && (
+        <Text fontSize="xs" color="app.errorFg" {...textProps}>
+          {message}
+        </Text>
+      )}
+    </Box>
+  );
+}
diff --git a/src/components/UnlockModal/UnlockModal.tsx b/src/components/UnlockModal/UnlockModal.tsx
index 3c75bfc..a9a56fd 100644
--- a/src/components/UnlockModal/UnlockModal.tsx
+++ b/src/components/UnlockModal/UnlockModal.tsx
@@ -4,6 +4,7 @@ import {
     poolContractId,
     stellarNetwork,
 } from "@/config";
+import FieldError from "@/components/FieldError/FieldError";
 import TransactionConfirmModal from "@/components/TransactionConfirmModal/TransactionConfirmModal";
 import { useErrorHandler } from "@/context/ErrorContext";
 import { useStellarWallet } from "@/context/StellarWalletContext";
@@ -38,7 +39,7 @@ import {
     Spinner,
     Text,
 } from "@chakra-ui/react";
-import { useEffect, useMemo, useRef, useState } from "react";
+import { useEffect, useId, useMemo, useRef, useState } from "react";
 
 type UnlockStep =
   | "idle"
@@ -89,6 +90,15 @@ export default function UnlockModal() {
     numericAmount >= 0.01 &&
     !!position &&
     numericAmount <= position.lockedAmount;
+  const amountError =
+    !!amount && !amountValid && position
+      ? numericAmount < 0.01
+        ? `Minimum unlock amount is 0.01 ${position.symbol}.`
+        : numericAmount > position.lockedAmount
+          ? `Amount exceeds locked balance of ${position.lockedAmount} ${position.symbol}.`
+          : "Enter a valid amount."
+      : null;
+  const amountErrorId = useId();
 
   const feePreview = useUnlockAssetsFeePreview({
     publicKey,
@@ -400,6 +410,8 @@ export default function UnlockModal() {
                     value={amount}
                     onChange={(e) => setAmount(e.target.value)}
                     isDisabled={!canUnlock || isProcessing}
+                    isInvalid={Boolean(amountError)}
+                    aria-describedby={amountErrorId}
                     borderColor="app.border"
                     bg="app.inputBg"
                     color="app.text"
@@ -452,15 +464,7 @@ export default function UnlockModal() {
                 </Box>
               </Flex>
 
-              {!!amount && !amountValid && (
-                <Text fontSize="xs" color="app.errorFg" role="alert">
-                  {numericAmount < 0.01
-                    ? `Minimum unlock amount is 0.01 ${position.symbol}.`
-                    : numericAmount > position.lockedAmount
-                      ? `Amount exceeds locked balance of ${position.lockedAmount} ${position.symbol}.`
-                      : "Enter a valid amount."}
-                </Text>
-              )}
+              <FieldError id={amountErrorId} message={amountError} />
 
               {amountValid && (
                 <Box border="1px solid #303030" borderRadius="2xl" p={3}>