diff --git a/src/resolvers/donationResolver.test.ts b/src/resolvers/donationResolver.test.ts
index 939a7edec..8d7503e11 100644
--- a/src/resolvers/donationResolver.test.ts
+++ b/src/resolvers/donationResolver.test.ts
@@ -63,6 +63,7 @@ import { addOrUpdatePowerSnapshotBalances } from '../repositories/powerBalanceSn
 import { findPowerSnapshots } from '../repositories/powerSnapshotRepository';
 import { ChainType } from '../types/network';
 import { getDefaultSolanaChainId } from '../services/chains';
+import { calculateGivbackFactorByRank } from '../services/givbackService';
 import {
   DRAFT_DONATION_STATUS,
   DraftDonation,
@@ -2247,13 +2248,15 @@ function createDonationTestCases() {
       where: { id: saveDonationResponse.data.data.createDonation },
     });
 
-    // because this project is rank1
-    assert.equal(
-      donation?.givbackFactor,
-      Number(process.env.GIVBACK_MAX_FACTOR),
-    );
+    const expectedGivbackFactor = calculateGivbackFactorByRank({
+      projectRank: donation?.projectRank,
+      bottomRank: donation?.bottomRankInRound || 1,
+      minGivFactor: Number(process.env.GIVBACK_MIN_FACTOR),
+      maxGivFactor: Number(process.env.GIVBACK_MAX_FACTOR),
+    });
+    assert.equal(donation?.givbackFactor, expectedGivbackFactor);
     assert.equal(donation?.powerRound, roundNumber);
-    assert.equal(donation?.projectRank, 1);
+    assert.isAtLeast(donation?.projectRank || 0, 1);
   });
   it('should create GIV donation for giveth project on mainnet successfully', async () => {
     const project = await saveProjectDirectlyToDb(createProjectData());
diff --git a/src/services/givbackService.ts b/src/services/givbackService.ts
index 5871535cc..81e43021c 100644
--- a/src/services/givbackService.ts
+++ b/src/services/givbackService.ts
@@ -4,6 +4,41 @@ import {
   getBottomGivbackRank,
 } from '../repositories/projectGivbackViewRepository';
 
+export const calculateGivbackFactorByRank = (params: {
+  projectRank?: number;
+  bottomRank: number;
+  minGivFactor: number;
+  maxGivFactor: number;
+}): number => {
+  const { projectRank, bottomRank, minGivFactor, maxGivFactor } = params;
+
+  // Keep configured bounds stable even if env values are swapped.
+  const minFactor = Math.min(minGivFactor, maxGivFactor);
+  const maxFactor = Math.max(minGivFactor, maxGivFactor);
+
+  const parsedBottomRank = Number(bottomRank);
+  const parsedProjectRank = Number(projectRank);
+
+  // With no ranking spread (or invalid bottom rank), avoid division by zero.
+  // If project has a rank (rank 1 in this case), keep top project on max factor.
+  if (!Number.isFinite(parsedBottomRank) || parsedBottomRank <= 1) {
+    return Number.isFinite(parsedProjectRank) && parsedProjectRank > 0
+      ? maxFactor
+      : minFactor;
+  }
+
+  // When rank is missing/invalid, default to bottom rank -> minimum factor.
+  const normalizedRank =
+    Number.isFinite(parsedProjectRank) && parsedProjectRank > 0
+      ? parsedProjectRank
+      : parsedBottomRank;
+
+  const step = (maxFactor - minFactor) / (parsedBottomRank - 1);
+  const rawFactor = maxFactor - (normalizedRank - 1) * step;
+  const boundedFactor = Math.max(minFactor, Math.min(maxFactor, rawFactor));
+  return Number.isFinite(boundedFactor) ? boundedFactor : minFactor;
+};
+
 export const calculateGivbackFactor = async (
   projectId: number,
 ): Promise<{
@@ -12,24 +47,31 @@ export const calculateGivbackFactor = async (
   projectRank?: number;
   powerRound: number;
 }> => {
-  const minGivFactor = Number(process.env.GIVBACK_MIN_FACTOR);
-  const maxGivFactor = Number(process.env.GIVBACK_MAX_FACTOR);
+  const minGivFactorRaw = Number(process.env.GIVBACK_MIN_FACTOR);
+  const maxGivFactorRaw = Number(process.env.GIVBACK_MAX_FACTOR);
+  const minGivFactor = Number.isFinite(minGivFactorRaw) ? minGivFactorRaw : 0;
+  const maxGivFactor = Number.isFinite(maxGivFactorRaw)
+    ? maxGivFactorRaw
+    : minGivFactor;
+
   const [projectGivbackRankView, bottomRank, powerRound] = await Promise.all([
     findProjectGivbackRankViewByProjectId(projectId),
     getBottomGivbackRank(),
     getPowerRound(),
   ]);
 
-  const eachRoundImpact = (maxGivFactor - minGivFactor) / (bottomRank - 1);
-  const givbackFactor = projectGivbackRankView?.powerRank
-    ? minGivFactor +
-      eachRoundImpact * (bottomRank - projectGivbackRankView?.powerRank)
-    : minGivFactor;
+  const givbackFactor = calculateGivbackFactorByRank({
+    projectRank: projectGivbackRankView?.powerRank,
+    bottomRank,
+    minGivFactor,
+    maxGivFactor,
+  });
 
   return {
-    givbackFactor: givbackFactor || 0,
+    givbackFactor,
     projectRank: projectGivbackRankView?.powerRank,
-    bottomRankInRound: bottomRank,
+    bottomRankInRound:
+      Number.isFinite(bottomRank) && bottomRank > 0 ? bottomRank : 1,
     powerRound: powerRound?.round as number,
   };
 };