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Reviewed · Prices checked October 2026 · How we calculate

Lime Calculator: How Much Lime Do I Need?

Enter the area and the lime rate from your soil test. You get the pounds and the bags to buy, and a warning when the dose should be split.

Inputs

Units
Shape
ft
ft
    lb / 1,000 sq ft

    No test? 40 to 50 lb is the extension rule of thumb.

    lb
    $

    Shopping list

    Updates as you type
    2bags

    of 40 lb lime: 80 lb for 2,000 sq ft at 40 lb per 1,000 sq ft

    Type your price per bag for the cost—
    Show the math
    Area: 50 × 40 ft = 2,000 sq ft2,000 sq ft ÷ 1,000 × 40 lb = 80 lb ÷ 40 lb bags = 2.00 → 2 bags

    The price you type is used for this estimate only; it isn't saved.

    How it works

    The formula

    lime = area ÷ 1,000 × rate
    bags = lime ÷ bag weight, rounded up

    Assumptions

    • Rate: soil test reports give lime in lb per 1,000 sq ft. Without a test, UNH Extension suggests 40 to 50 lb per 1,000 sq ft if you haven't limed in several years.
    • Split big doses: more than 50 lb per 1,000 sq ft should go down in parts, the second 3 to 6 months after the first (UNH Extension).
    • Pelletized and ground lime are applied at the same rate by weight; pellets are easier to spread. Some reports give the rate for a lime with a stated neutralizing value; check the label if yours differs.

    Worked example

    A 2,000 sq ft lawn at 40 lb per 1,000 sq ft

    1. 2,000 ÷ 1,000 × 40 = 80 lb
    2. 80 ÷ 40 lb bags = 2 bags

    40 lb bags at 40 lb per 1,000 sq ft

    40 lb bags of lime by lawn size at 40 lb per 1,000 sq ft
    LawnLime40 lb bags
    1,000 sq ft40 lb1
    2,500 sq ft100 lb3
    5,000 sq ft200 lb5
    10,000 sq ft400 lb10

    Questions people ask

    How much lime do I need per 1,000 sq ft?

    Whatever your soil test says. Without one, 40 to 50 lb per 1,000 sq ft is the usual extension rule of thumb for a lawn that hasn't been limed in years (UNH).

    Can I put down too much lime?

    Yes. Lime raises the soil pH, and too high a pH locks up nutrients. Test every few years, and split doses over 50 lb per 1,000 sq ft.

    When should I lime my lawn?

    Fall and early spring are common, since rain and freezing work it into the soil. It takes months to change the pH, so don't expect a quick change.