diff --git a/internal/api/httpinvoce/controller.go b/internal/api/httpinvoce/controller.go
index 6d84c31..93cbdc4 100644
--- a/internal/api/httpinvoce/controller.go
+++ b/internal/api/httpinvoce/controller.go
@@ -29,13 +29,19 @@ func (s Service) createInvoice(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	invoice, err := s.invoice.Generate(req.Creditor, req.Debtor, time.Duration(req.DurationThreshold), req.HourlyRate, repos)
+	invoice, report, err := s.invoice.Generate(req.Creditor, req.Debtor, time.Duration(req.DurationThreshold), req.HourlyRate, repos)
 	if err != nil {
 		log.Println("error while processing invoice:", err)
 		fmt.Fprint(w, "internal server error")
 		w.WriteHeader(http.StatusInternalServerError)
 		return
 	}
+	// if no time has to be billed aka if bill for 0 CHF
+	if report.Total() <= time.Duration(0) {
+		s.sendErr(w, http.StatusNotFound, "no suitable issues to be billed")
+		return
+	}
+
 	w.Header().Set("Content-type", "application/pdf")
 	w.Header().Set(
 		"Content-Disposition",
@@ -51,7 +57,6 @@ func (s Service) createInvoice(w http.ResponseWriter, r *http.Request) {
 
 func (s Service) sendInvoice(w http.ResponseWriter, r *http.Request) {
 	var req sendReq
-
 	err := json.NewDecoder(r.Body).Decode(&req)
 	if err != nil {
 		s.sendErrf(w, http.StatusBadRequest, "cannot read body: %v", err)
@@ -63,11 +68,16 @@ func (s Service) sendInvoice(w http.ResponseWriter, r *http.Request) {
 		s.sendErr(w, 500, err.Error())
 		return
 	}
-	invoice, err := s.invoice.Generate(req.Invoice.Creditor, req.Invoice.Debtor, time.Duration(req.Invoice.DurationThreshold), req.Invoice.HourlyRate, repos)
+	invoice, report, err := s.invoice.Generate(req.Invoice.Creditor, req.Invoice.Debtor, time.Duration(req.Invoice.DurationThreshold), req.Invoice.HourlyRate, repos)
 	if err != nil {
 		s.sendErr(w, http.StatusInternalServerError, "error while processing invoice:", err)
 		return
 	}
+	// if no time has to be billed aka if bill for 0 CHF
+	if report.Total() <= time.Duration(0) {
+		s.sendErr(w, http.StatusNotFound, "no suitable issues to be billed")
+		return
+	}
 
 	invoiceData, err := io.ReadAll(invoice)
 	if err != nil {
diff --git a/internal/api/httpinvoce/resource.go b/internal/api/httpinvoce/resource.go
index f8a0e13..952de50 100644
--- a/internal/api/httpinvoce/resource.go
+++ b/internal/api/httpinvoce/resource.go
@@ -8,6 +8,7 @@ import (
 	"git.schreifuchs.ch/lou-taylor/accounting/internal/email"
 	"git.schreifuchs.ch/lou-taylor/accounting/pkg/invoice"
 	"git.schreifuchs.ch/lou-taylor/accounting/pkg/invoice/model"
+	"git.schreifuchs.ch/lou-taylor/accounting/pkg/invoice/report"
 )
 
 type Service struct {
@@ -21,7 +22,7 @@ func New(log *slog.Logger, invoice invoicer, mail mailer) *Service {
 }
 
 type invoicer interface {
-	Generate(creditor, deptor model.Entity, mindur time.Duration, rate float64, repos []invoice.Repo) (document io.ReadCloser, err error)
+	Generate(creditor, deptor model.Entity, mindur time.Duration, rate float64, repos []invoice.Repo) (document io.ReadCloser, report report.Report, err error)
 }
 
 type mailer interface {
diff --git a/pkg/invoice/invoice.go b/pkg/invoice/invoice.go
index 46aab6a..bb5e43c 100644
--- a/pkg/invoice/invoice.go
+++ b/pkg/invoice/invoice.go
@@ -10,7 +10,7 @@ import (
 	"git.schreifuchs.ch/lou-taylor/accounting/pkg/invoice/report"
 )
 
-func (s *Service) Generate(creditor, deptor model.Entity, mindur time.Duration, rate float64, repos []Repo) (document io.ReadCloser, err error) {
+func (s *Service) Generate(creditor, deptor model.Entity, mindur time.Duration, rate float64, repos []Repo) (document io.ReadCloser, r *report.Report, err error) {
 	var is []*gitea.Issue
 	for _, repo := range repos {
 		iss, _, err := s.gitea.ListRepoIssues(
@@ -24,7 +24,7 @@ func (s *Service) Generate(creditor, deptor model.Entity, mindur time.Duration,
 			},
 		)
 		if err != nil {
-			return nil, err
+			return nil, nil, err
 		}
 
 		is = append(is, iss...)
@@ -37,7 +37,7 @@ func (s *Service) Generate(creditor, deptor model.Entity, mindur time.Duration,
 		},
 	)
 	issues := issue.FromGiteas(is, mindur)
-	r := report.New(
+	r = report.New(
 		issues,
 		creditor,
 		deptor,