Liquid Fertilizer Dilution Calculator

Why dilution accuracy matters for plants

Liquid fertilizers deliver nutrients fast, but small measuring errors scale quickly. For a 10 L batch, a 10 mL mistake can shift dose by 1 mL/L. Seedlings, herbs, and container plants often show burn first, while underfeeding slows growth and reduces flowering. This calculator standardizes mixing so every batch matches your intent.

Three methods that match common labels

Use the target concentration method when you know a stock strength and a desired ppm. Use the parts ratio method for directions like 1:100 or 1:200. Use the label-rate method for dosing guidance such as 5 mL per liter or 1 fl oz per gallon. Each method returns concentrate volume, water volume, and a repeatable ratio.

Example check: stock 20 g/L equals 20,000 mg/L. For a 10 L batch at 200 ppm, V1 = (200×10)/20,000 = 0.1 L, or 100 mL. Water becomes 9.9 L, confirming the settings. Repeat the same approach for other targets to catch unit mix-ups before you ever measure anything.

Concentration notes and practical conversions

The calculator treats ppm as mg/L for water-based solutions, which is standard for mixing guidance. When stock is entered as % (w/v), it assumes 1% equals 10 g/L, or 10,000 mg/L. It also converts gallons to liters and fl oz to mL, helping you work from metric labels or household measures without redoing math.

Batch planning and cost awareness

Planning batches prevents waste. If your label rate is 5 mL/L and you mix 12 L, you need 60 mL concentrate. A 1 L bottle provides about 16 similar batches. Tracking these numbers supports purchasing decisions, seasonal schedules, and consistent nutrition during vegetative growth, blooming, or fruit set.

Mixing workflow for reliable results

Measure water first, then add concentrate, then top up to final volume. Stir or shake thoroughly, especially for thick concentrates. Keep a simple log of method, batch size, and date. The built-in CSV and PDF exports make it easy to save a record for troubleshooting and repeatable performance across your garden.

FAQs

1) Is ppm the same as mg/L in this calculator?

Yes, for water-based mixes ppm is treated as mg/L. This matches common fertilizer and irrigation guidance, and it keeps dilution calculations consistent across different batch volumes and units.

2) What if my label gives a dilution like 1:200?

Choose the parts ratio method, enter stock parts as 1 and water parts as 200. The tool scales that ratio to your batch size and returns the exact concentrate and water amounts.

3) How does the % (w/v) option work?

It assumes percent weight-per-volume, where 1% equals 10 g/L. The calculator converts that to mg/L internally, then applies C1×V1 = C2×V2 to compute the concentrate volume.

4) Can I mix in gallons but export metric results?

Yes. You can enter final volume in gallons, and the result shows both liters and gallons. The CSV and PDF exports include both unit systems for easier measurement and record keeping.

5) Why does it warn that a target may be unreachable?

If the requested target concentration is too high compared with the stock strength, the required concentrate would exceed the final batch volume. The tool flags this to prevent impossible or unsafe mixes.

6) Should I always follow the calculator over the label?

No. Use the calculator to interpret label directions accurately, but always respect the product label and plant sensitivity. When unsure, start at a lower dose and observe plant response before increasing.