diff --git a/tools/fastswap-miles/cost_estimator.go b/tools/fastswap-miles/cost_estimator.go
index 4808642e2..26a0e1b81 100644
--- a/tools/fastswap-miles/cost_estimator.go
+++ b/tools/fastswap-miles/cost_estimator.go
@@ -8,8 +8,18 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	"github.com/ethereum/go-ethereum/common"
 )
 
+// Percentile of recent fastswap bid_cost used as the per-sweep bid proxy
+// (the sweep tx is itself a fastswap). p75 = under-promise.
+const sweepBidGlobalPercentile = 0.75
+
+// Fallback bid used when the percentile query returns NULL (cold start /
+// no processed rows yet). Post-fix realized p75 ≈ 4e-5 ETH.
+const sweepBidFallbackEth = 4e-5
+
 // costEstimateLookbackDays is the rolling window over which per-token sweep
 // overhead percentiles are computed.
 const costEstimateLookbackDays = 14
@@ -34,9 +44,11 @@ const costEstimateLastResort = 0.001 // ETH
 // upfront miles awarding. Estimates are refreshed periodically from
 // fastswap_miles realized sweep data.
 type costEstimate struct {
-	// PerRowOverhead is the estimated sweep overhead per user row, in ETH.
-	// This is the value subtracted in the miles formula in lieu of realized
-	// pro-rata sweep gas.
+	// PerRowOverhead is the estimated sweep overhead per user row, in ETH —
+	// the sum of pro-rata sweep gas and pro-rata sweep bid. This is the value
+	// subtracted in the miles formula in lieu of realized values for the
+	// (still-pending) sweep that will eventually convert this row's surplus
+	// tokens to ETH. See Refresh for the two components.
 	PerRowOverhead float64
 
 	// Source describes how this estimate was computed (for observability).
@@ -57,16 +69,24 @@ type costEstimator struct {
 	db     *sql.DB
 	logger *slog.Logger
 
+	// Lowercased hex of the executor address and WETH address. Used to
+	// identify executor sweep rows (user_address = executor, output = WETH)
+	// when computing the per-token sweep bid contribution.
+	executorAddr string
+	wethAddr     string
+
 	mu        sync.RWMutex
 	estimates map[string]costEstimate // key: lowercased token hex
 	lastFresh time.Time
 }
 
-func newCostEstimator(db *sql.DB, logger *slog.Logger) *costEstimator {
+func newCostEstimator(db *sql.DB, logger *slog.Logger, executorAddr, wethAddr common.Address) *costEstimator {
 	return &costEstimator{
-		db:        db,
-		logger:    logger,
-		estimates: make(map[string]costEstimate),
+		db:           db,
+		logger:       logger,
+		executorAddr: strings.ToLower(executorAddr.Hex()),
+		wethAddr:     strings.ToLower(wethAddr.Hex()),
+		estimates:    make(map[string]costEstimate),
 	}
 }
 
@@ -87,8 +107,10 @@ func (c *costEstimator) Get(token string) costEstimate {
 }
 
 // Refresh recomputes per-token estimates from realized fastswap_miles data
-// over the configured lookback window. This is the only method that touches
-// the database; intended to be called periodically by a background goroutine.
+// over the configured lookback window. PerRowOverhead is the sum of two
+// terms: per-token p25/p75 of pro-rata sweep gas (existing) plus per-token
+// (n_sweeps × global_bid_p75 / n_user_rows) for the sweep tx's own bid.
+// Both scale together with batch size.
 func (c *costEstimator) Refresh(ctx context.Context) error {
 	// Filter to ETH-input rows so per_row_oh isolates pure sweep_overhead.
 	// ERC20-input rows have user_gas baked into (surplus_eth - net_profit_eth),
@@ -149,6 +171,22 @@ GROUP BY output_token`, costEstimateLookbackDays))
 		return fmt.Errorf("iterate cost estimates: %w", err)
 	}
 
+	// Fold per-token sweep bid contribution into PerRowOverhead. A failure
+	// here is logged but non-fatal — the gas-only overhead is still a usable
+	// estimate and the alternative would be skipping the refresh entirely.
+	bidByToken, err := c.computePerTokenSweepBidEth(ctx)
+	if err != nil {
+		c.logger.Warn("sweep bid contribution refresh failed; falling back to gas-only overhead",
+			slog.Any("error", err))
+	} else {
+		for token, est := range fresh {
+			if bid, ok := bidByToken[token]; ok && bid > 0 {
+				est.PerRowOverhead += bid
+				fresh[token] = est
+			}
+		}
+	}
+
 	c.mu.Lock()
 	c.estimates = fresh
 	c.lastFresh = time.Now()
@@ -156,10 +194,69 @@ GROUP BY output_token`, costEstimateLookbackDays))
 
 	c.logger.Info("cost estimates refreshed",
 		slog.Int("tokens", len(fresh)),
+		slog.Int("tokens_with_sweep_bid", len(bidByToken)),
 		slog.Duration("window", costEstimateLookbackDays*24*time.Hour))
 	return nil
 }
 
+// computePerTokenSweepBidEth returns per-row sweep bid contribution (ETH)
+// keyed by lowercased output_token. Single round trip: joins per-token
+// executor sweep counts × per-token user-row counts × global bid p75 (with
+// fallback when no processed rows exist).
+func (c *costEstimator) computePerTokenSweepBidEth(ctx context.Context) (map[string]float64, error) {
+	query := fmt.Sprintf(`
+SELECT s.token, s.n_sweeps, u.n_users, COALESCE(b.p, %f) AS bid_p75
+FROM (
+  SELECT LOWER(input_token) AS token, COUNT(*) AS n_sweeps
+  FROM mevcommit_57173.fastswap_miles
+  WHERE LOWER(user_address) = ?
+    AND swap_type = 'eth_weth'
+    AND LOWER(output_token) = ?
+    AND block_timestamp >= NOW() - INTERVAL %d DAY
+  GROUP BY input_token
+) s
+JOIN (
+  SELECT LOWER(output_token) AS token, COUNT(*) AS n_users
+  FROM mevcommit_57173.fastswap_miles
+  WHERE swap_type = 'erc20'
+    AND LOWER(user_address) != ?
+    AND block_timestamp >= NOW() - INTERVAL %d DAY
+  GROUP BY output_token
+) u ON u.token = s.token
+CROSS JOIN (
+  SELECT percentile_approx(CAST(bid_cost AS DOUBLE)/1e18, %f) AS p
+  FROM mevcommit_57173.fastswap_miles
+  WHERE processed = 1
+    AND bid_cost IS NOT NULL
+    AND CAST(bid_cost AS DOUBLE) > 0
+    AND block_timestamp >= NOW() - INTERVAL %d DAY
+) b
+`, sweepBidFallbackEth, costEstimateLookbackDays, costEstimateLookbackDays,
+		sweepBidGlobalPercentile, costEstimateLookbackDays)
+
+	rows, err := c.db.QueryContext(ctx, query, c.executorAddr, c.wethAddr, c.executorAddr)
+	if err != nil {
+		return nil, fmt.Errorf("query per-token sweep bid: %w", err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	out := make(map[string]float64)
+	for rows.Next() {
+		var token string
+		var nSweeps, nUsers int
+		var bidEth float64
+		if err := rows.Scan(&token, &nSweeps, &nUsers, &bidEth); err != nil {
+			c.logger.Warn("scan per-token sweep bid failed", slog.Any("error", err))
+			continue
+		}
+		if nSweeps <= 0 || nUsers <= 0 || bidEth <= 0 {
+			continue
+		}
+		out[token] = float64(nSweeps) * bidEth / float64(nUsers)
+	}
+	return out, rows.Err()
+}
+
 // Run starts a background loop that refreshes estimates on the configured
 // interval. Returns when the context is cancelled. Performs an immediate
 // initial refresh on startup so estimates are warm before the first miles
diff --git a/tools/fastswap-miles/cost_estimator_test.go b/tools/fastswap-miles/cost_estimator_test.go
index 10048650f..dc18d0c56 100644
--- a/tools/fastswap-miles/cost_estimator_test.go
+++ b/tools/fastswap-miles/cost_estimator_test.go
@@ -5,6 +5,8 @@ import (
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/ethereum/go-ethereum/common"
 )
 
 func newTestEstimator() *costEstimator {
@@ -16,7 +18,7 @@ func newTestEstimator() *costEstimator {
 
 func TestCostEstimator_Get_NoData_FallsBackToLastResort(t *testing.T) {
 	// Exercise the real constructor so it's not unused.
-	c := newCostEstimator(nil, slog.Default())
+	c := newCostEstimator(nil, slog.Default(), common.Address{}, common.Address{})
 	got := c.Get("0xdeadbeef")
 	if got.Source != "default_no_data" {
 		t.Errorf("source = %q, want default_no_data", got.Source)
@@ -91,3 +93,19 @@ func TestCostEstimateLastResort_Reasonable(t *testing.T) {
 		t.Errorf("costEstimateLastResort = %v, expected within [1e-4, 1e-2] sanity range", costEstimateLastResort)
 	}
 }
+
+func TestCostEstimator_Constructor_LowercasesAddresses(t *testing.T) {
+	// Sweep-bid lookup queries compare against LOWER(user_address) and
+	// LOWER(output_token), so the addresses stored on the estimator MUST be
+	// lowercased. A mixed-case stored value would silently match zero rows
+	// and the sweep bid term would never fire.
+	exec := common.HexToAddress("0x959DAD78D5B68986a43cD270134A2704a990aa68")
+	weth := common.HexToAddress("0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2")
+	c := newCostEstimator(nil, slog.Default(), exec, weth)
+	if c.executorAddr != strings.ToLower(exec.Hex()) {
+		t.Errorf("executorAddr = %q, want %q", c.executorAddr, strings.ToLower(exec.Hex()))
+	}
+	if c.wethAddr != strings.ToLower(weth.Hex()) {
+		t.Errorf("wethAddr = %q, want %q", c.wethAddr, strings.ToLower(weth.Hex()))
+	}
+}
diff --git a/tools/fastswap-miles/main.go b/tools/fastswap-miles/main.go
index 3d807d5e5..881f94436 100644
--- a/tools/fastswap-miles/main.go
+++ b/tools/fastswap-miles/main.go
@@ -246,7 +246,7 @@ func main() {
 				return fmt.Errorf("newPriceOracle: %w", err)
 			}
 			cfg.PriceOracle = priceOracle
-			cfg.CostEstimator = newCostEstimator(db, logger)
+			cfg.CostEstimator = newCostEstimator(db, logger, executorAddr, weth)
 			cfg.GasBuffer = newGasBuffer(db, logger)
 			cfg.SweepClock = newSweepClock()
 			reconciliation := newReconciliationMonitor(db, logger,