How To Calibrate Kitchen Scales | Spot-On Results

Dialed-in grams save recipes. If your food scale drifts, breads proof oddly, espresso shots pull light, and macros miss the mark. The fix isn’t guesswork. With a few checks and a short procedure, you can bring a home scale back to dependable readings and prove it with simple tests.

Calibrating A Home Food Scale Step-By-Step

This walkthrough fits most digital models with a “CAL” or “MODE” sequence. If your unit manual says otherwise, follow it. The goal is the same: set zero, apply known mass, and store that reference in memory.

Prep The Scale

• Place the unit on a firm, level counter away from drafts and vibrations.
• Install fresh batteries or a full charge. Weak power causes jumpy digits.
• Let the device sit for 10 minutes so temperature equalizes.
• Remove bowls and mats. The pan should be clean and dry.

Run The Calibration

1. Turn the scale on and press Zero/Tare to show 0.0.
2. Enter the calibration sequence (often holding UNIT + ZERO while powering on until “CAL” appears). Your model may prompt for a target weight.
3. Place the requested test weight gently in the center. Wait for the stable icon, then confirm per the prompt.
4. Remove the weight when asked, let the display return to zero, and exit the mode.
5. Verify by weighing the same object three times. Readings should match within your scale’s division (e.g., ±1 g).

Early Reference Guide

Use proper calibration masses whenever possible. If you’re just checking sanity, coins and measured water can help, with notes below.

Reference Item	Nominal Mass	Practical Notes
Class F/ASTM Calibration Weight	1 g to 1 kg	Best choice; pick a value near your typical loads.
U.S. Nickel	5.000 g	Mint spec; stack for 10, 20, 50 g checks.
U.S. Quarter	5.670 g	Use sleeves or gloves to avoid residue.
U.S. Dime	2.268 g	Useful for fine checks; combine with nickels.
Tap Water	~1 g per mL	Best at 20–25°C; use a narrow, tared vessel.
Espresso Basket + Water	Varies	Great for repeat checks at a barista station.

When You Don’t Have Lab Weights

Coins are manufactured to tight specs, so they’re handy spot checks. A single nickel is 5.000 g and a dime is 2.268 g; both values come from the U.S. Mint’s public table of coin specifications. Water is a decent stand-in too: near room temperature, 100 mL approaches 100 g. For the most reliable results, calibrate with proper masses and use coins or water only to confirm that readings haven’t wandered.

Safe Workarounds

• Coins: Build stacks that match your readout divisions. Keep them clean and dry.
• Water: Tare an empty cup, pour to a measured volume, and weigh. Aim for 20–25°C to reduce density error.
• Pan Centering: Place the item dead center and avoid touching the counter as you pour.

For background on device classes and tolerances used across weighing devices, see the current edition of NIST Handbook 44. If you want deeper reading, consult your brand’s manual.

Recalibrating Digital Food Scales For Accuracy

Do a full calibration after moving the unit, after a battery change, or anytime you notice a steady offset. Many models lose stored constants when power dips. If your model supports “linear calibration,” run it with a lower weight and a second, higher weight to improve accuracy across the entire range.

Span And Linearity

Choose a test point close to your typical loads. If you bake bread, 500 g is a smart span weight. If you weigh small doses, 20 g is a better anchor. To check linearity, confirm readings at 10%, 50%, and 90% of capacity. Errors should stay inside one or two divisions at each point on a good home unit.

Repeatability Checks

1. Weigh the same nickel stack five times, lifting between readings.
2. Record the values. The spread should be tight (e.g., 100.0, 100.0, 100.1, 100.0, 100.0 g).
3. If the spread widens as mass increases, repeat the calibration with weights closer to your real use.

Fine-Tuning And Proving Accuracy

Corner Load Test

Place a 200 g object in the center and then near each corner, keeping the item entirely on the pan. Differences larger than one division mean the geometry or feet need attention. Level the feet, re-seat the pan, and try again.

Tare Integrity

Tare with your mixing bowl, then add a known 100 g. Remove the bowl and weigh the 100 g alone. Both readings should match. If the tared reading is off while direct weighing is fine, the tare circuit is drifting and a fresh calibration usually fixes it.

Room Conditions And Handling

• Vibration and airflow nudge readings. Keep the unit a few inches from HVAC vents.
• Heat changes mass readings. Let hot cookware cool before weighing.
• Do not press on the pan while pouring; that transfers load from your hand.

Choosing Reference Weights

For best results, use proper masses that match your scale’s resolution. A common home unit reads to 1 g and tops out near 5 kg. A set of 50 g, 100 g, 200 g, 500 g, and 1 kg covers bread flour, coffee, and meal prep. Keep the weights in a small case, handle them with clean, dry hands, and don’t drop them on the pan. If you need formal classes for lab work, look for ASTM or OIML markings sold as “Class F” or better. Those tolerances are designed for field checks of devices like retail scales. NIST publications explain the metrology behind them, but for kitchen use you mainly need clean, stable masses and a consistent routine.

Why Water Isn’t Perfect

Water density changes with temperature, so 1 mL equals 1 g only near a specific point. At 20 °C, pure water sits near 0.998 g/mL; at 25 °C, the value drops closer to 0.997 g/mL. That small shift adds up across large volumes, which is why water is fine for a check but not the last word for calibration. When precision matters, stick with proper masses and use water only to sanity-check your span across a couple of points.

Verification Routine After Calibration

Run three checks: low (10–20 g), mid (≈500 g), and high (just under capacity). Log the date and readings. A steady bias hints at a stored shift; scatter points to vibration or power.

Units, Readability, And Resolution

Resolution is the smallest step your scale can display. For many models it’s 1 g, while coffee scales and jewelry scales show 0.1 g. Don’t attempt to calibrate at 0.1 g with coins; the tolerance on a single coin is larger than that step. Pick a span weight at least a few hundred divisions for a stable result. If you run dual-point calibration, choose weights that bracket your common loads so both the low end and the high end measure cleanly.

How Often Should You Recalibrate?

Home cooks can set a monthly cadence, or sooner if the unit travels or switches batteries. Baristas and macro-trackers do better with a weekly check because their tolerances are tighter. Any time you notice drift bigger than one division, run the process right away.

If you cook daily, pair the calibration with your trash day or coffee bean refill; a fixed trigger makes the habit stick without thinking and keeps every recipe, pour, and portion aligned week after week.

Manufacturer Nuances You Might See

Buttons and prompts vary. Some models show “CAL 200” to request a 200 g mass; others ask you to cycle through options with the unit key. A few units need you to short a hidden switch on the base. That’s normal—follow your manual. As a reference point, A&D’s SJ series, a common commercial design, enters calibration by holding the re-zero and unit keys while powering on, then asking for a zero point and a span weight. That pattern mirrors what you’ll see on many brands.

Common Mistakes And Easy Fixes

Symptom	Likely Cause	Fix
Numbers creep up or down slowly	Drafts or warm cookware	Move away from vents; let items cool; add a wind shield.
Readings jump around	Low battery or bouncy counter	Swap cells; use a solid surface; avoid overhanging cutting boards.
Always heavy or always light	Calibration stored wrong	Run CAL with the exact requested weight; restart and verify.
Accurate at 50 g but off at 500 g	Poor linearity	Use a two-point routine if available; choose a higher span weight.
Different readings in corners	Pan not seated or feet uneven	Re-seat pan; level the feet; repeat corner test.
Tare drifts during a pour	Finger on the bowl or vibration	Let the scale settle; don’t touch the pan; pour smoothly.

Care, Storage, And Routine

• Wipe with a damp cloth. Avoid soaking the display or buttons.
• Store flat. Heavy items on top can strain the load cell.
• Remove batteries if you’ll store the unit for months.
• Keep calibration masses in a small sealed bag to prevent grime.

When To Replace The Scale

Devices age. If the unit won’t hold zero, fails corner tests badly, or needs constant recalibration, the load cell or electronics may be past their best days. At that point, replacement is cheaper than chasing errors. Newer models add faster filters, better feet, and more stable spans, which means fewer surprises during service.

Quick Checklist You Can Print

• Level surface, fresh power, settled temperature.
• Zero the display.
• Run CAL exactly as prompted.
• Use proper weights; coins and water only for checks.
• Verify repeatability, linearity, and corners.
• Log your results and date; repeat on a schedule.

Enjoy.