diff --git a/packages/tendermint-rpc/src/dates.spec.ts b/packages/tendermint-rpc/src/dates.spec.ts
index dfdf0b94..25862012 100644
--- a/packages/tendermint-rpc/src/dates.spec.ts
+++ b/packages/tendermint-rpc/src/dates.spec.ts
@@ -1,10 +1,20 @@
 import { ReadonlyDate } from "readonly-date";
 
-import { DateTime, DateWithNanoseconds, fromRfc3339WithNanoseconds, toRfc3339WithNanoseconds } from "./dates";
+import {
+  DateTime,
+  DateWithNanoseconds,
+  fromRfc3339WithNanoseconds,
+  fromSeconds,
+  toRfc3339WithNanoseconds,
+  toSeconds,
+} from "./dates";
 
 describe("dates", () => {
   describe("fromRfc3339WithNanoseconds", () => {
     it("works", () => {
+      expect(fromRfc3339WithNanoseconds("2020-12-15T10:57:26Z").nanoseconds).toEqual(0);
+      expect(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.7Z").nanoseconds).toEqual(0);
+      expect(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.77Z").nanoseconds).toEqual(0);
       expect(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.778Z").nanoseconds).toEqual(0);
       expect(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.7789Z").nanoseconds).toEqual(900000);
       expect(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.77809Z").nanoseconds).toEqual(90000);
@@ -52,6 +62,107 @@ describe("dates", () => {
     });
   });
 
+  describe("fromSeconds", () => {
+    it("works", () => {
+      {
+        const date = fromSeconds(1608029846);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 0);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 1);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.000000001Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 10);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.000000010Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 100);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.000000100Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 1000);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.000001000Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 10000);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.000010000Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 100000);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.000100000Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 1000000);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.001000000Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 10000000);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.010000000Z"));
+      }
+      {
+        const date = fromSeconds(1608029846, 100000000);
+        expect(date).toEqual(fromRfc3339WithNanoseconds("2020-12-15T10:57:26.100000000Z"));
+      }
+    });
+
+    it("throws for nanos out of range", () => {
+      expect(() => fromSeconds(1608029846, 1000000000)).toThrow();
+      expect(() => fromSeconds(1608029846, -1)).toThrow();
+      expect(() => fromSeconds(1608029846, 1.2)).toThrow();
+      expect(() => fromSeconds(1608029846, NaN)).toThrow();
+    });
+  });
+
+  describe("toSeconds", () => {
+    it("works", () => {
+      {
+        const date = fromRfc3339WithNanoseconds("2020-12-15T10:57:26Z");
+        expect(toSeconds(date)).toEqual({ seconds: 1608029846, nanos: 0 });
+      }
+      {
+        const date = fromRfc3339WithNanoseconds("2020-12-15T10:57:26.7Z");
+        expect(toSeconds(date)).toEqual({ seconds: 1608029846, nanos: 700000000 });
+      }
+      {
+        const date = fromRfc3339WithNanoseconds("2020-12-15T10:57:26.77Z");
+        expect(toSeconds(date)).toEqual({ seconds: 1608029846, nanos: 770000000 });
+      }
+      {
+        const date = fromRfc3339WithNanoseconds("2020-12-15T10:57:26.778Z");
+        expect(toSeconds(date)).toEqual({ seconds: 1608029846, nanos: 778000000 });
+      }
+      {
+        const date = fromRfc3339WithNanoseconds("2020-12-15T10:57:26.7789Z");
+        expect(toSeconds(date)).toEqual({ seconds: 1608029846, nanos: 778900000 });
+      }
+      {
+        const date = fromRfc3339WithNanoseconds("2020-12-15T10:57:26.77809Z");
+        expect(toSeconds(date)).toEqual({ seconds: 1608029846, nanos: 778090000 });
+      }
+      {
+        const date = fromRfc3339WithNanoseconds("2020-12-15T10:57:26.778009Z");
+        expect(toSeconds(date)).toEqual({ seconds: 1608029846, nanos: 778009000 });
+      }
+      {
+        const date = fromRfc3339WithNanoseconds("2020-12-15T10:57:26.7780009Z");
+        expect(toSeconds(date)).toEqual({ seconds: 1608029846, nanos: 778000900 });
+      }
+      {
+        const date = fromRfc3339WithNanoseconds("2020-12-15T10:57:26.77800009Z");
+        expect(toSeconds(date)).toEqual({ seconds: 1608029846, nanos: 778000090 });
+      }
+      {
+        const date = fromRfc3339WithNanoseconds("2020-12-15T10:57:26.778000009Z");
+        expect(toSeconds(date)).toEqual({ seconds: 1608029846, nanos: 778000009 });
+      }
+    });
+  });
+
   describe("DateTime", () => {
     it("decodes a string", () => {
       expect(DateTime.decode("2020-12-15T10:57:26.778Z").nanoseconds).toEqual(0);
diff --git a/packages/tendermint-rpc/src/dates.ts b/packages/tendermint-rpc/src/dates.ts
index 4a15ccfc..fd75d7ea 100644
--- a/packages/tendermint-rpc/src/dates.ts
+++ b/packages/tendermint-rpc/src/dates.ts
@@ -1,4 +1,5 @@
 import { fromRfc3339 } from "@cosmjs/encoding";
+import { Uint32 } from "@cosmjs/math";
 import { ReadonlyDate } from "readonly-date";
 
 export interface ReadonlyDateWithNanoseconds extends ReadonlyDate {
@@ -25,6 +26,30 @@ export function toRfc3339WithNanoseconds(dateTime: ReadonlyDateWithNanoseconds):
   return `${millisecondIso.slice(0, -1)}${nanoseconds.padStart(6, "0")}Z`;
 }
 
+export function fromSeconds(seconds: number, nanos = 0): DateWithNanoseconds {
+  const checkedNanos = new Uint32(nanos).toNumber();
+  if (checkedNanos > 999_999_999) {
+    throw new Error("Nano seconds must not exceed 999999999");
+  }
+  const out: DateWithNanoseconds = new Date(seconds * 1000 + Math.floor(checkedNanos / 1000000));
+  out.nanoseconds = checkedNanos % 1000000;
+  return out;
+}
+
+/**
+ * Calculates the UNIX timestamp in seconds as well as the nanoseconds after the given second.
+ *
+ * This is useful when dealing with external systems like the protobuf type
+ * [.google.protobuf.Timestamp](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#google.protobuf.Timestamp)
+ * or any other system that does not use millisecond precision.
+ */
+export function toSeconds(date: ReadonlyDateWithNanoseconds): { seconds: number; nanos: number } {
+  return {
+    seconds: Math.floor(date.getTime() / 1000),
+    nanos: (date.getTime() % 1000) * 1000000 + (date.nanoseconds ?? 0),
+  };
+}
+
 /** @deprecated Use fromRfc3339WithNanoseconds/toRfc3339WithNanoseconds instead */
 export class DateTime {
   /** @deprecated Use fromRfc3339WithNanoseconds instead */
diff --git a/packages/tendermint-rpc/src/index.ts b/packages/tendermint-rpc/src/index.ts
index c6584a41..1d762ea2 100644
--- a/packages/tendermint-rpc/src/index.ts
+++ b/packages/tendermint-rpc/src/index.ts
@@ -5,7 +5,9 @@ export {
   DateTime,
   ReadonlyDateWithNanoseconds,
   fromRfc3339WithNanoseconds,
+  fromSeconds,
   toRfc3339WithNanoseconds,
+  toSeconds,
 } from "./dates";
 export {
   AbciInfoRequest,