diff --git a/packages/sdk/src/index.ts b/packages/sdk/src/index.ts
index e144a09e..4352341b 100644
--- a/packages/sdk/src/index.ts
+++ b/packages/sdk/src/index.ts
@@ -24,3 +24,4 @@ export {
   encodeBech32Pubkey,
   encodeSecp256k1Pubkey,
 } from "./pubkey";
+export { findSequenceForSignedTx } from "./sequence";
diff --git a/packages/sdk/src/sequence.spec.ts b/packages/sdk/src/sequence.spec.ts
new file mode 100644
index 00000000..e5d8f4cd
--- /dev/null
+++ b/packages/sdk/src/sequence.spec.ts
@@ -0,0 +1,30 @@
+import { findSequenceForSignedTx } from "./sequence";
+import response1 from "./testdata/txresponse1.json";
+import response2 from "./testdata/txresponse2.json";
+import response3 from "./testdata/txresponse3.json";
+
+// Those values must match ./testdata/txresponse*.json
+const chainId = "testing";
+const accountNumber = 4;
+
+describe("sequence", () => {
+  describe("findSequenceForSignedTx", () => {
+    it("works", async () => {
+      const current = 100; // what we get from GET /auth/accounts/{address}
+      expect(await findSequenceForSignedTx(response1.tx, chainId, accountNumber, current)).toEqual(10);
+      // We know response3.height > response1.height, so the sequence must be at least 10+1
+      expect(await findSequenceForSignedTx(response3.tx, chainId, accountNumber, current, 11)).toEqual(19);
+      // We know response3.height > response2.height > response1.height, so the sequence must be at least 10+1 and smaller than 19
+      expect(await findSequenceForSignedTx(response2.tx, chainId, accountNumber, 19, 11)).toEqual(13);
+    });
+
+    it("returns undefined when sequence is not in range", async () => {
+      expect(await findSequenceForSignedTx(response1.tx, chainId, accountNumber, 5)).toBeUndefined();
+      expect(await findSequenceForSignedTx(response1.tx, chainId, accountNumber, 20, 11)).toBeUndefined();
+      expect(await findSequenceForSignedTx(response1.tx, chainId, accountNumber, 20, 50)).toBeUndefined();
+
+      // upper bound is not included in the possible results
+      expect(await findSequenceForSignedTx(response1.tx, chainId, accountNumber, 10)).toBeUndefined();
+    });
+  });
+});
diff --git a/packages/sdk/src/sequence.ts b/packages/sdk/src/sequence.ts
new file mode 100644
index 00000000..8a53e897
--- /dev/null
+++ b/packages/sdk/src/sequence.ts
@@ -0,0 +1,46 @@
+import { Secp256k1, Secp256k1Signature, Sha256 } from "@iov/crypto";
+
+import { makeSignBytes } from "./encoding";
+import { decodeSignature } from "./signature";
+import { CosmosSdkTx } from "./types";
+
+/**
+ * Serach for sequence s with `min` <= `s` < `upperBound` to find the sequence that was used to sign the transaction
+ *
+ * @param tx The signed transaction
+ * @param chainId The chain ID for which this transaction was signed
+ * @param accountNumber The account number for which this transaction was signed
+ * @param upperBound The upper bound for the testing, i.e. sequence must be lower than this value
+ * @param min The lowest sequence that is tested
+ *
+ * @returns the sequence if a match was found and undefined otherwise
+ */
+export async function findSequenceForSignedTx(
+  tx: CosmosSdkTx,
+  chainId: string,
+  accountNumber: number,
+  upperBound: number,
+  min = 1,
+): Promise<number | undefined> {
+  const firstSignature = tx.value.signatures.find(() => true);
+  if (!firstSignature) throw new Error("Signature missing in tx");
+
+  const { pubkey, signature } = decodeSignature(firstSignature);
+  const secp256keSignature = new Secp256k1Signature(signature.slice(0, 32), signature.slice(32, 64));
+
+  for (let s = min; s < upperBound; s++) {
+    // console.log(`Trying sequence ${s}`);
+    const signBytes = makeSignBytes(
+      tx.value.msg,
+      tx.value.fee,
+      chainId,
+      tx.value.memo || "",
+      accountNumber,
+      s,
+    );
+    const prehashed = new Sha256(signBytes).digest();
+    const valid = await Secp256k1.verifySignature(secp256keSignature, prehashed, pubkey);
+    if (valid) return s;
+  }
+  return undefined;
+}
diff --git a/packages/sdk/src/testdata/txresponse1.json b/packages/sdk/src/testdata/txresponse1.json
new file mode 100644
index 00000000..703ea696
--- /dev/null
+++ b/packages/sdk/src/testdata/txresponse1.json
@@ -0,0 +1,57 @@
+{
+  "height": "15888",
+  "txhash": "672DEDE8EF4DE8B5818959F417CCA357079D4D7A19C4B65443C7FBF8176AABF9",
+  "raw_log": "[{\"msg_index\":0,\"log\":\"\",\"events\":[{\"type\":\"message\",\"attributes\":[{\"key\":\"action\",\"value\":\"send\"},{\"key\":\"sender\",\"value\":\"cosmos1pkptre7fdkl6gfrzlesjjvhxhlc3r4gmmk8rs6\"},{\"key\":\"module\",\"value\":\"bank\"}]},{\"type\":\"transfer\",\"attributes\":[{\"key\":\"recipient\",\"value\":\"cosmos1t70qnpr0az8tf7py83m4ue5y89w58lkjmx0yq2\"},{\"key\":\"amount\",\"value\":\"75000ucosm\"}]}]}]",
+  "logs": [
+    {
+      "msg_index": 0,
+      "log": "",
+      "events": [
+        {
+          "type": "message",
+          "attributes": [
+            { "key": "action", "value": "send" },
+            { "key": "sender", "value": "cosmos1pkptre7fdkl6gfrzlesjjvhxhlc3r4gmmk8rs6" },
+            { "key": "module", "value": "bank" }
+          ]
+        },
+        {
+          "type": "transfer",
+          "attributes": [
+            { "key": "recipient", "value": "cosmos1t70qnpr0az8tf7py83m4ue5y89w58lkjmx0yq2" },
+            { "key": "amount", "value": "75000ucosm" }
+          ]
+        }
+      ]
+    }
+  ],
+  "gas_wanted": "200000",
+  "gas_used": "65407",
+  "tx": {
+    "type": "cosmos-sdk/StdTx",
+    "value": {
+      "msg": [
+        {
+          "type": "cosmos-sdk/MsgSend",
+          "value": {
+            "from_address": "cosmos1pkptre7fdkl6gfrzlesjjvhxhlc3r4gmmk8rs6",
+            "to_address": "cosmos1t70qnpr0az8tf7py83m4ue5y89w58lkjmx0yq2",
+            "amount": [{ "denom": "ucosm", "amount": "75000" }]
+          }
+        }
+      ],
+      "fee": { "amount": [{ "denom": "ucosm", "amount": "5000" }], "gas": "200000" },
+      "signatures": [
+        {
+          "pub_key": {
+            "type": "tendermint/PubKeySecp256k1",
+            "value": "A08EGB7ro1ORuFhjOnZcSgwYlpe0DSFjVNUIkNNQxwKQ"
+          },
+          "signature": "US7oH8S/8TxVrtBQkOhHxAM+oDB2spNAEawgh6H8CCFLRMOJK+uvQZZ6ceUgUsvDbxwCz7re1RU272fymMYRZQ=="
+        }
+      ],
+      "memo": "My first payment"
+    }
+  },
+  "timestamp": "2020-02-14T11:25:55Z"
+}
diff --git a/packages/sdk/src/testdata/txresponse2.json b/packages/sdk/src/testdata/txresponse2.json
new file mode 100644
index 00000000..0d1a37f9
--- /dev/null
+++ b/packages/sdk/src/testdata/txresponse2.json
@@ -0,0 +1,57 @@
+{
+  "height": "16456",
+  "txhash": "7BFE4B93AF190F60132C62D08FDF50BE462FBCE374EB13D3FD0C32461E771EC0",
+  "raw_log": "[{\"msg_index\":0,\"log\":\"\",\"events\":[{\"type\":\"message\",\"attributes\":[{\"key\":\"action\",\"value\":\"send\"},{\"key\":\"sender\",\"value\":\"cosmos1pkptre7fdkl6gfrzlesjjvhxhlc3r4gmmk8rs6\"},{\"key\":\"module\",\"value\":\"bank\"}]},{\"type\":\"transfer\",\"attributes\":[{\"key\":\"recipient\",\"value\":\"cosmos1t70qnpr0az8tf7py83m4ue5y89w58lkjmx0yq2\"},{\"key\":\"amount\",\"value\":\"75000ucosm\"}]}]}]",
+  "logs": [
+    {
+      "msg_index": 0,
+      "log": "",
+      "events": [
+        {
+          "type": "message",
+          "attributes": [
+            { "key": "action", "value": "send" },
+            { "key": "sender", "value": "cosmos1pkptre7fdkl6gfrzlesjjvhxhlc3r4gmmk8rs6" },
+            { "key": "module", "value": "bank" }
+          ]
+        },
+        {
+          "type": "transfer",
+          "attributes": [
+            { "key": "recipient", "value": "cosmos1t70qnpr0az8tf7py83m4ue5y89w58lkjmx0yq2" },
+            { "key": "amount", "value": "75000ucosm" }
+          ]
+        }
+      ]
+    }
+  ],
+  "gas_wanted": "200000",
+  "gas_used": "65407",
+  "tx": {
+    "type": "cosmos-sdk/StdTx",
+    "value": {
+      "msg": [
+        {
+          "type": "cosmos-sdk/MsgSend",
+          "value": {
+            "from_address": "cosmos1pkptre7fdkl6gfrzlesjjvhxhlc3r4gmmk8rs6",
+            "to_address": "cosmos1t70qnpr0az8tf7py83m4ue5y89w58lkjmx0yq2",
+            "amount": [{ "denom": "ucosm", "amount": "75000" }]
+          }
+        }
+      ],
+      "fee": { "amount": [{ "denom": "ucosm", "amount": "5000" }], "gas": "200000" },
+      "signatures": [
+        {
+          "pub_key": {
+            "type": "tendermint/PubKeySecp256k1",
+            "value": "A08EGB7ro1ORuFhjOnZcSgwYlpe0DSFjVNUIkNNQxwKQ"
+          },
+          "signature": "ltvd9Rb3RF4zjbUVrpDpkok34g+py7XR8ZcM0tZUYRxxVdcMEin010x+ZFd/mOuutPj9fDmSENnienc/yi4msw=="
+        }
+      ],
+      "memo": "My first payment"
+    }
+  },
+  "timestamp": "2020-02-14T11:35:41Z"
+}
diff --git a/packages/sdk/src/testdata/txresponse3.json b/packages/sdk/src/testdata/txresponse3.json
new file mode 100644
index 00000000..8ffd0727
--- /dev/null
+++ b/packages/sdk/src/testdata/txresponse3.json
@@ -0,0 +1,57 @@
+{
+  "height": "20730",
+  "txhash": "625BC75E697F73DA037387C34002BB2F682E7ACDCC4E015D3E90420516C6D0C8",
+  "raw_log": "[{\"msg_index\":0,\"log\":\"\",\"events\":[{\"type\":\"message\",\"attributes\":[{\"key\":\"action\",\"value\":\"send\"},{\"key\":\"sender\",\"value\":\"cosmos1pkptre7fdkl6gfrzlesjjvhxhlc3r4gmmk8rs6\"},{\"key\":\"module\",\"value\":\"bank\"}]},{\"type\":\"transfer\",\"attributes\":[{\"key\":\"recipient\",\"value\":\"cosmos1t70qnpr0az8tf7py83m4ue5y89w58lkjmx0yq2\"},{\"key\":\"amount\",\"value\":\"75000ucosm\"}]}]}]",
+  "logs": [
+    {
+      "msg_index": 0,
+      "log": "",
+      "events": [
+        {
+          "type": "message",
+          "attributes": [
+            { "key": "action", "value": "send" },
+            { "key": "sender", "value": "cosmos1pkptre7fdkl6gfrzlesjjvhxhlc3r4gmmk8rs6" },
+            { "key": "module", "value": "bank" }
+          ]
+        },
+        {
+          "type": "transfer",
+          "attributes": [
+            { "key": "recipient", "value": "cosmos1t70qnpr0az8tf7py83m4ue5y89w58lkjmx0yq2" },
+            { "key": "amount", "value": "75000ucosm" }
+          ]
+        }
+      ]
+    }
+  ],
+  "gas_wanted": "200000",
+  "gas_used": "65407",
+  "tx": {
+    "type": "cosmos-sdk/StdTx",
+    "value": {
+      "msg": [
+        {
+          "type": "cosmos-sdk/MsgSend",
+          "value": {
+            "from_address": "cosmos1pkptre7fdkl6gfrzlesjjvhxhlc3r4gmmk8rs6",
+            "to_address": "cosmos1t70qnpr0az8tf7py83m4ue5y89w58lkjmx0yq2",
+            "amount": [{ "denom": "ucosm", "amount": "75000" }]
+          }
+        }
+      ],
+      "fee": { "amount": [{ "denom": "ucosm", "amount": "5000" }], "gas": "200000" },
+      "signatures": [
+        {
+          "pub_key": {
+            "type": "tendermint/PubKeySecp256k1",
+            "value": "A08EGB7ro1ORuFhjOnZcSgwYlpe0DSFjVNUIkNNQxwKQ"
+          },
+          "signature": "eOFGl1tIHDMv3JdCK9fRSikVbYUD8+B0ksb3dJFya8MPYgpEpdSA7zZc+5n/cW6LR/BJdib4nqmJQv1yD9lm3g=="
+        }
+      ],
+      "memo": "My first payment"
+    }
+  },
+  "timestamp": "2020-02-14T12:48:56Z"
+}
diff --git a/packages/sdk/types/index.d.ts b/packages/sdk/types/index.d.ts
index 0a4c02d7..dcb618cc 100644
--- a/packages/sdk/types/index.d.ts
+++ b/packages/sdk/types/index.d.ts
@@ -23,3 +23,4 @@ export {
   encodeBech32Pubkey,
   encodeSecp256k1Pubkey,
 } from "./pubkey";
+export { findSequenceForSignedTx } from "./sequence";
diff --git a/packages/sdk/types/sequence.d.ts b/packages/sdk/types/sequence.d.ts
new file mode 100644
index 00000000..70d38469
--- /dev/null
+++ b/packages/sdk/types/sequence.d.ts
@@ -0,0 +1,19 @@
+import { CosmosSdkTx } from "./types";
+/**
+ * Serach for sequence s with `min` <= `s` < `upperBound` to find the sequence that was used to sign the transaction
+ *
+ * @param tx The signed transaction
+ * @param chainId The chain ID for which this transaction was signed
+ * @param accountNumber The account number for which this transaction was signed
+ * @param upperBound The upper bound for the testing, i.e. sequence must be lower than this value
+ * @param min The lowest sequence that is tested
+ *
+ * @returns the sequence if a match was found and undefined otherwise
+ */
+export declare function findSequenceForSignedTx(
+  tx: CosmosSdkTx,
+  chainId: string,
+  accountNumber: number,
+  upperBound: number,
+  min?: number,
+): Promise<number | undefined>;