Load Cell Output Calculator
Calculate ideal load-cell output using rated capacity, applied load, mV/V sensitivity, excitation voltage and zero offset.
SEN-002 focuses on calibrated load-cell output behavior. Raw strain-gauge resistance change belongs to SEN-001, while arbitrary bridge resistance imbalance belongs to SEN-003.
Engineering tool
Load Cell Output Calculator
Calculate load-cell full-scale output, actual mV signal, load from measured output, sensitivity, excitation and zero balance using the ideal mV/V model.
Calculation mode
Parameter panel
Negative applied load is valid for bipolar tension/compression analysis.
Result console
- Load Fraction
- 0.5
- Load Percent
- 50%
- Full-Scale Signal Output
- 10 mV
- Actual Signal Output
- 5 mV
- Total Output
- 5.2 mV
- Output
- 5.2e+3µV
- Output Ratio
- 1.04mV/V
- Status
- Within Rated Range
- Safe Overload Reference
- 150 kg
- Ultimate Overload Reference
- 300 kg
Safe overload is not the recommended continuous measurement range. Higher excitation increases signal but can also increase self-heating.
Load cell formula audit
| Load Fraction Definition | η = applied load / rated capacity. |
|---|---|
| Quantity Mode | Mass-equivalent units are compared as a ratio; kg, g and lb are not converted to force in the core model. |
| Sensitivity Unit | mV/V means millivolts of full-scale output per volt of excitation. |
| mV/V Conversion | Sratio = sensitivity(mV/V) / 1000. |
| Full-Scale Output | VFS = Sratio × VEX. |
| Partial Load Output | Vsignal = VFS × η. |
| Zero Offset Model | VOUT = Vzero + Vsignal. |
| Inverse Load | η = (Vmeasured - Vzero) / (Sratio × VEX). |
| Sensitivity Solver | Sratio = (Vmeasured - Vzero) / (VEX × η). |
| Excitation Solver | VEX = Vsignal / (Sratio × η). |
| Zero Balance | Zero balance mV/V = Vzero / VEX × 1000. |
| Offset %FS | Offset %FS = Vzero / VFS × 100%. |
| Range Convention | Unipolar mode expects 0 to rated capacity. |
| Safe Overload Boundary | Safe overload is a datasheet reference, not the rated measurement range. |
| Tolerance Model | V1 models sensitivity, excitation and zero-balance range only. |
| Excluded Error Terms | Nonlinearity, hysteresis, creep, temperature drift, amplifier and ADC errors are documented but not solved here. |
Formula reference
Load Cell Output Formulas
The calculator uses the ideal linear mV/V load-cell model and keeps zero offset separate from signal output.
Sratio = S(mV/V) / 1000η = Applied Load / Rated CapacityVFS = Sratio × VEXVsignal = VFS × ηVOUT = Vzero + Vsignalη = (Vmeasured - Vzero) / (Sratio × VEX)Load = η × Rated CapacityS(mV/V) = 1000 × (Vmeasured - Vzero) / (VEX × η)VEX = Vsignal / (Sratio × η)Zero Balance (mV/V) = Vzero / VEX × 1000Variable definitions
- S
- load-cell sensitivity in mV/V
- Sratio
- sensitivity converted to V/V
- VEX
- excitation voltage
- η
- applied load / rated capacity
- Vzero
- zero balance or tare offset
- Vsignal
- load-dependent bridge signal
- VOUT
- total measured output
Load Cell Formula Audit
| Load Fraction Definition | η = applied load / rated capacity. |
|---|---|
| Sensitivity Unit Definition | mV/V means millivolts of full-scale output per volt of excitation. |
| mV/V to V/V Conversion | Sratio = sensitivity(mV/V) / 1000. |
| Full-Scale Output Formula | VFS = Sratio × VEX. |
| Partial-Load Output Formula | Vsignal = VFS × η. |
| Zero Offset Model | VOUT = Vzero + Vsignal. |
| Inverse Load Formula | η = (Vmeasured - Vzero) / (Sratio × VEX). |
| Sensitivity Solver | Sratio = (Vmeasured - Vzero) / (VEX × η). |
| Excitation Solver | VEX = Vsignal / (Sratio × η). |
| Zero Balance Definition | Zero balance mV/V = Vzero / VEX × 1000. |
| Offset %FS Definition | Offset %FS = Vzero / VFS × 100%. |
| Unipolar / Bipolar Convention | Unipolar expects 0 to rated capacity; bipolar allows signed tension/compression load. |
| Rated Capacity Boundary | Rated capacity remains the nominal measurement range. |
| Safe Overload Boundary | Safe overload is not a continuous rated measurement range. |
| Tolerance Model | Sensitivity, excitation and zero-balance range are included. |
| Temperature / Nonlinearity Boundary | Nonlinearity, hysteresis, creep and temperature drift are documented but not solved. |
Worked Examples
100 kg cell at 50 kg
Known: 2.0 mV/V, 5 V excitation
Load fraction = 0.5; FS output = 10 mV; signal = 5 mV.
100 kg full load
Known: 2.0 mV/V, 5 V excitation
Output = 10 mV.
25 kg on same cell
Known: 100 kg rated, 2.0 mV/V, 5 V
Output = 2.5 mV.
Higher excitation
Known: 2.0 mV/V, 10 V excitation
Full-scale output = 20 mV.
Measured signal to load
Known: 5 mV, 2.0 mV/V, 5 V, 100 kg rated
Calculated load = 50 kg.
Zero offset included
Known: Measured total 5.5 mV, zero offset 0.5 mV
Tared signal = 5 mV; load = 50 kg.
3 mV/V at 3.3 V
Known: Full-scale rated output
FS output = 9.9 mV.
Solve sensitivity
Known: 50 kg on 100 kg, 5 V, 5 mV signal
Sensitivity = 2.0 mV/V.
Solve excitation
Known: 2.0 mV/V, 50% load, 5 mV target
Excitation = 5 V.
Zero load sensitivity solve
Known: Applied load = 0
Rejected because sensitivity cannot be solved from zero load response.
Zero load excitation solve
Known: Applied load = 0
Rejected because excitation cannot be solved from zero load response.
Over-rated measured load
Known: Signal corresponds to 120 kg on a 100 kg cell
Shows 120% / over rated capacity; no clamp.
Bipolar compression
Known: Rated ±100 N, applied -50 N
Signal = -50% full-scale by sign convention.
Zero balance
Known: 0.2 mV zero output, 5 V excitation
Zero balance = 0.04 mV/V.
Offset percent
Known: 10 mV full scale, 0.2 mV zero
Offset = 2% FS.
Sensitivity and excitation tolerance
Known: Sensitivity ±1%, excitation ±2%
Minimum and maximum output are calculated from worst-case corners.
mV/V conversion
Known: 2.0 mV/V
Sensitivity ratio = 0.002 V/V.
Voltage conversion
Known: 10 mV
10 mV = 10000 µV.
Mass-unit ratio
Known: 50 kg / 100 kg = 50000 g / 100000 g
Load fraction remains 0.5.
Force-unit ratio
Known: 100 lbf / 200 lbf
Load fraction = 0.5.
Forward/inverse round trip
Known: Load → output → load
Recovered load matches the original input.
Sensitivity round trip
Known: Output → sensitivity → output
Recovered signal output matches measured data.
Engineering Notes
| Load Cell | A load cell is a calibrated mechanical sensor assembly that usually converts force or mass-equivalent load into a bridge signal. |
|---|---|
| Rated Capacity | Rated capacity is the nominal measurement range, not the overload limit. |
| Rated Output | Rated output is commonly specified as mV/V at full-scale load. |
| Sensitivity | Sensitivity should be taken from the load-cell datasheet or calibration certificate. |
| mV/V | 2 mV/V means 2 mV full-scale output per volt of excitation. |
| Excitation Voltage | Higher excitation increases signal but also bridge power and self-heating. |
| Full-Scale Output | Full-scale output equals mV/V sensitivity multiplied by excitation. |
| Zero Balance | Zero balance is the output offset at no load. |
| Tare | Taring subtracts a measured zero offset electronically. |
| Bridge Sensor | SEN-002 uses rated mV/V behavior and does not solve raw bridge resistors. |
| Overload | Safe overload should not be treated as a continuous measurement range. |
| Nonlinearity | Nonlinearity is separate from sensitivity tolerance. |
| Hysteresis | Hysteresis depends on loading history and is not included in the ideal linear model. |
| Creep | Creep is time-dependent output change under load and is not included here. |
| Temperature Effect | Temperature can affect zero and span. |
| Instrumentation Amplifier | Small millivolt bridge signals often require low-noise amplification or a load-cell ADC. |
Common Mistakes
- Treating 2 mV/V as 2 V/V.
- Forgetting excitation voltage.
- Multiplying sensitivity by load without dividing by rated capacity.
- Mixing applied load and rated capacity units across quantity dimensions.
- Not subtracting zero offset from measured output.
- Treating safe overload as normal range.
- Silently clamping load above rated capacity.
- Assuming higher excitation is always better.
- Confusing sensitivity tolerance with total accuracy.
- Ignoring nonlinearity.
- Ignoring hysteresis.
- Ignoring creep.
- Ignoring temperature zero and span shift.
- Confusing mV/V with mV.
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FAQ
What does mV/V mean for a load cell?
mV/V means millivolts of full-scale bridge output per volt of excitation. A 2 mV/V load cell produces 2 mV at full load for every 1 V of excitation.
How do I calculate load-cell output voltage?
Convert sensitivity from mV/V to V/V, multiply by excitation voltage, then multiply by applied load divided by rated capacity.
How do I calculate full-scale load-cell output?
Full-scale output equals sensitivity ratio multiplied by excitation voltage. For 2 mV/V and 5 V excitation, the full-scale output is 10 mV.
How do I calculate load from measured millivolts?
Subtract the zero offset from measured output, then divide by sensitivity ratio times excitation voltage to get load fraction.
How do I calculate load-cell sensitivity?
Use a known applied load, measured output, zero offset and excitation voltage. Sensitivity is signal output divided by excitation and load fraction.
How does excitation voltage affect output?
Output is proportional to excitation voltage, but excessive excitation can heat the bridge and increase drift.
What is rated capacity?
Rated capacity is the nominal measurement range of the load cell. It is not the same as safe overload or ultimate overload.
What is zero balance?
Zero balance is the electrical output at zero applied load, often specified as an offset in mV/V or percent of full scale.
What is load-cell tare?
Tare subtracts measured zero output from subsequent readings. It does not fix mechanical mounting errors or damaged sensors.
What is the difference between rated capacity and safe overload?
Rated capacity is the measurement range. Safe overload is a short-term datasheet limit and should not be treated as normal operating range.
Can a load cell measure tension and compression?
Some load cells are designed for bipolar tension and compression. This calculator includes bipolar mode for signed output analysis.
Why is load-cell output only a few millivolts?
Most bridge load cells produce only a few mV at full scale, so instrumentation amplifiers or high-resolution ADCs are commonly required.
Do I need an instrumentation amplifier?
Many load-cell systems need a low-noise instrumentation amplifier or dedicated load-cell ADC front end because the bridge signal is small.
How does temperature affect a load cell?
Temperature can shift zero balance, span sensitivity, mechanical behavior and bridge resistance.
What are nonlinearity, hysteresis and creep?
They are real load-cell error terms that are not part of the simple ideal mV/V model. Use datasheet values and calibration for precision systems.
How is a load cell different from a raw strain gauge?
A raw strain gauge changes resistance with strain. A load cell is a calibrated mechanical sensor assembly that usually outputs a rated mV/V signal.
Engineering Disclaimer
This calculator provides ideal mV/V load-cell arithmetic. Critical weighing, force and safety systems require the actual datasheet, mechanical review, calibration, excitation limits, amplifier/ADC design, temperature compensation and measurement validation.