{{ visualTitle }} {{ visualAreaLabel }} {{ visualRateLabel }} {{ visualPassLabel }}
Metric uses m and kg; imperial uses ft and lb for package-label matching.
Use measured area when an app, survey, or property sketch already gives the lawn size.
Enter one side of the lawn area being seeded.
Enter the second side; it uses the same unit list as length.
Enter the full circle diameter, not the radius.
Enter only the area that will receive seed.
Match the product label: new lawn rates are usually higher than overseeding rates.
Choose the label detail you have; the calculator derives the matching seed rate for every result.
Choose a common turf type, then verify the exact product label before buying.
Use the label rate for new lawn, overseeding, or repair. Editing this switches the profile to Custom.
Enter the product bag weight, such as 10 kg, 7 lb, 25 lb, or 50 lb.
Example: a 25 lb bag that covers 5,000 sq ft derives a 5 lb / 1,000 sq ft rate.
Use 0 to keep the seed quantity plan without cost estimates.
$ / bag
{{ allowance_percent }}%
Use 5-15% for normal projects; raise it for irregular edges or patchy prep.
Use 1 for a single lawn area.
sections
Leave at 0 when the entered area already excludes non-lawn pockets.
%
100% keeps label math unchanged; lower values increase raw seed to buy.
%
Use 1 for individual bags, 2 for two-packs, or larger multiples for bundled orders.
bags
Two passes is common for even coverage; one pass keeps the full amount together.
passes
Leave at 0 for quantity-only planning or when tax is unknown.
%
{{ orderCaption }}
Item Value Planning note Copy
{{ row.label }} {{ row.value }} {{ row.note }}
Planning rates are starting points; product labels and local seed blends take priority.
Seed profile New lawn Overseed Current bag covers Best fit Note Copy
{{ row.label }} {{ row.newRate }} {{ row.overseedRate }} {{ row.currentCoverage }} {{ row.fit }} {{ row.note }}
Compare common package sizes against the current seed requirement.
Package Bags Ordered seed Leftover Coverage at rate Estimated cost Copy
{{ row.packageLabel }} {{ row.bags }} {{ row.orderedDisplay }} {{ row.leftoverDisplay }} {{ row.coverageDisplay }} {{ row.costDisplay }} 

                    

                

            

        

    

                

                

                    

                        

                            Tags: Gardening, Productivity
                        

                        

                            
                            
                        

                    

                

            

        

    


                    
        

        

        

            

            
        

        


                    

                

                

                    

                                                    

                                
                            

                                                    

                                
                            

                                                    

                                
                            

                                                    

                                
                            

                                            

                

            

        
                                                                                                                                                                                                                                                        
        

        

            
            

                Customize

                

                    

                        

                            
                            
                        


                        

                            
                            
                        


                        

                            
                            
                        

                    


                    

                        Advanced

                        

                            

                                
                                

                                    
                                    
                                

                            


                            

                                
                                

                                    
                                    
                                

                            


                            

                                
                                

                                    
                                    :
                                    
                                

                            


                            

                                
                                

                                    
                                    
                                

                            


                            

                                

                                    
                                    
                                

                            


                            

                                

                                    
                                    
                                

                            


                            

                                
                                
                            


                            

                                
                                
                            

                        

                    

                

            

            
        


        

            
            
            
        


        
        

    

    

        

  

    
    
Grass seed planning starts with the area that will actually receive seed and the rate printed on the product label. New lawns, overseeding, and bare-patch repair use different rates because they are solving different turf problems. Bare soil needs enough seed to establish a stand from scratch, while overseeding usually adds plants into an existing lawn without burying the old turf under too much competition.

    
Seed labels usually express application rate as weight per area, such as pounds per 1,000 square feet or kilograms per 100 square meters. Some packages instead advertise how much area one bag covers. Both forms describe the same relationship: bag weight, covered area, and seed rate. The rate should match the job type and the grass species or blend, not just the bag size on the shelf.

    

      
        
        
          
          Seedable area
          exclude beds
          
          Label rate
          weight per area
          
          Allowance
          overlap + PLS
          
          Seed to spread
          divide by passes
          
          Bags
          round up
          
          The order is driven by seedable area, label rate, field allowance, and whole-bag rounding.
        
      
    

    
Several real-world details can change the purchase amount. Irregular lawns need exclusions for walks, beds, patios, and bare sections that are not being seeded. Spreaders overlap at edges and turns. Product labels may list pure live seed, a measure that combines seed purity and germination. When pure live seed is lower than 100%, more product is needed to place the intended amount of viable seed.

    
Buying seed is also a packaging problem. The exact mathematical need may be 18.4 lb, but a store may sell only 10 lb or 25 lb bags. Whole-bag rounding creates leftover coverage, and that leftover can be useful for touch-up if it is stored dry and used while the product remains viable.

  






  

    
How to Use This Tool:

    
    
      
  1. Select metric or imperial units, then choose the lawn footprint you have: length by width, diameter, or a measured area from a plan, map, or measuring wheel.
    2. 
      
  2. Choose the application mode: new lawn, overseed, or bare patch. Match the product label whenever the label gives different rates.
    3. 
      
  3. Enter the label rate directly, or switch to bag coverage when the package tells you how much area one bag covers.
    4. 
      
  4. Set the bag weight and optional bag price. Whole-bag rounding, estimated cost, and leftover seed depend on those fields.
    5. 
      
  5. Use Advanced for preparation allowance, excluded area, section count, pure live seed percentage, bag bundle rounding, pass count, and tax.
    6. 
      
  6. Read Seed Order first, then use Rate Guide, Bag Scenarios, Coverage Curve, and JSON when you need label comparisons, package-size planning, a chart, or a structured export.
    7. 
    

  






  

    
Interpreting Results:

    
The primary order shows whole bags to buy. The more important audit numbers are the seedable area, label basis, base seed, seed to spread, ordered seed weight, leftover seed, and coverage from the ordered seed. If the rate came from bag coverage, the result also shows the derived rate so you can compare it with product labels that use pounds per 1,000 square feet.

    

      

        
          

            Result
            Meaning
          

        
        
          
Base seed at label rateSeed weight before allowance and pure-live-seed adjustment.

          
Seed to spreadAdjusted weight after field allowance and pure live seed percentage.

          
Whole bags to buyPackage count rounded up to the selected bundle size.

          
Leftover seedOrdered weight minus spread weight. This is useful for touch-ups but should not be forced onto the lawn.

          
Coverage from ordered seedApproximate area the purchased seed could cover at the selected label rate before field loss.

        
      

    

    
High label-rate badges usually mean the product or job type needs review. They can be correct for some turf types or renovations, but they can also signal that a new-lawn rate was accidentally used for overseeding. Light rates deserve the same check, especially on bare soil where thin seeding can leave open space for weeds.

  






  

    
Technical Details:

    
Seed quantity is a unit-normalized area calculation. The lawn footprint is converted into square feet and square meters, exclusions reduce the seedable area, and the label rate is normalized to pounds per 1,000 square feet. Metric rates are converted through the same normalized rate so the final seed weight can be displayed in pounds or kilograms.

    
Allowance and pure live seed act in opposite-looking ways. A field allowance increases seed to cover overlap, edge loss, and touch-up. Pure live seed percentage divides the amount because a lower viable fraction means more product must be spread to deliver the same viable seed.

    
Formula Core

    
Let A be seedable area in square feet and R be the label rate in pounds per 1,000 square feet. The base seed requirement is:

    
      
        B
        =
        A1000
        ×
        R
      
    
    
After field allowance a and pure live seed factor p, the amount to spread is:

    
      
        S
        =
        
          B×(1+a)
          p
        
      
    
    
Whole-bag ordering rounds spread weight S up by bag weight W and selected bundle size g:

    
      
        N
        =
        ceil
        (
        
          S/W
          g
        
        )
        ×
        g
      
    
    

      

        
          

            Concept
            Technical role
          

        
        
          
New lawn rateUsually higher because bare soil needs enough plants for full establishment.

          
Overseed rateUsually lower because existing turf already covers part of the area.

          
Bag coverageConverted into a rate by dividing bag weight by covered area and scaling to 1,000 sq ft.

          
Pure live seedEntered as a percentage and used as the divisor for viable-seed adjustment.

          
Pass countSplits seed to spread into equal passes so cross-hatching or repeated light passes can be planned.

        
      

    

    
For example, 4,000 sq ft at 6 lb per 1,000 sq ft needs 24 lb before adjustments. A 10% allowance raises that to 26.4 lb. If pure live seed is 90%, the spread weight becomes 29.33 lb. With 10 lb bags and one-bag bundle rounding, the order is 3 bags, or 30 lb, leaving about 0.67 lb for touch-up.

  






  

    
Limitations and Accuracy Notes:

    
    
      
  • Product labels, local extension guidance, species, cultivar, coating, and planting season should override generic planning profiles.
    • 
      
  • Seed coatings can increase bag weight without increasing viable seed count in the same proportion. Read the label before comparing bags by weight alone.
    • 
      
  • The calculator does not decide soil preparation, irrigation schedule, fertilizer need, weed control, or ideal planting date.
    • 
      
  • Cost estimates use the entered bag price and tax only. They do not include starter fertilizer, compost, topdressing, equipment rental, or labor.
    • 
    

  






  

    
Worked Examples:

    
Measured backyard overseed. A 2,500 sq ft existing lawn at 3 lb per 1,000 sq ft needs 7.5 lb before allowance. With a 10 lb bag, the order rounds to one bag and leaves enough seed for thin spots.

    
New fescue area. A 1,200 sq ft bare-soil repair at 8 lb per 1,000 sq ft needs 9.6 lb before allowance. Two smaller bags may reduce leftover compared with one large bag if the unit price is similar.

    
Coverage-label product. A 25 lb bag that covers 5,000 sq ft derives a 5 lb per 1,000 sq ft rate. That rate should still be checked against the label's job type, because the same product may list different coverage for new lawn and overseeding.

  






  

    
FAQ:

    
Should I use the new-lawn or overseeding rate?
Use the label's new-lawn rate for bare soil or full renovation. Use the overseeding rate when seed is being added into an existing stand of grass.

    
Why does pure live seed increase the amount to spread?
Pure live seed represents viable seed. If the viable fraction is below 100%, more product is needed to deliver the same viable amount.

    
Can I spread the leftover seed too?
Do not force leftover seed onto the lawn if it would exceed the intended rate. Save it for touch-ups when storage conditions and label dates allow.

    
Why do bag sizes change the order but not the exact seed need?
The exact need comes from area and rate. Bag size only changes how much you must buy after rounding to whole packages.

  






  

    
Glossary:

    

      
Seedable area
The lawn area that will receive seed after excluding beds, hardscape, and other unseeded sections.

      
Label rate
The product's recommended seed weight per area for a specific job type.

      
Pure live seed
A seed-label quality measure combining purity and germination into the viable seed fraction.

      
Overseeding
Spreading seed into existing turf to improve density, repair thinning, or introduce a different grass blend.

    

  






  

    
References: