Humidity Ratio Calculator
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Calculate
Dry-bulb temperature of the air
Relative humidity of the air (0–100%)
Overview
Humidity ratio (W) — also called moisture content or mixing ratio — is the mass of water vapor per unit mass of dry air. It is the fundamental moisture variable in HVAC psychrometrics because it remains constant through any sensible heating or cooling process and changes only when moisture is added or removed.
Unlike relative humidity, which varies with temperature even when no moisture is added or removed, humidity ratio is an absolute measure of moisture content. Two air streams at different temperatures but the same humidity ratio contain exactly the same amount of water vapor per pound (or kilogram) of dry air. This makes W the correct variable for latent load calculations, mixing calculations, and dehumidification analysis.
This calculator derives humidity ratio from dry-bulb temperature combined with one of four moisture inputs: relative humidity, wet-bulb temperature, dew point temperature, or direct entry. It also computes the corresponding dew point temperature, partial vapor pressure, degree of saturation (μ), and saturation humidity ratio (W_sat) at the given dry-bulb temperature. All calculations use the Magnus approximation for saturation vapor pressure at standard atmospheric pressure, consistent with ASHRAE Handbook — Fundamentals psychrometric formulations.
How to Use This Calculator
Enter dry-bulb temperature — in °C or °F.
Select moisture input type — choose from Relative Humidity, Wet-Bulb Temperature, Dew Point Temperature, or Direct Entry.
Enter relative humidity — in %.
Enter wet-bulb temperature — in °C or °F.
Enter dew point temperature — in °C or °F.
Enter humidity ratio — in g/kg or gr/lb.
Click "Calculate" — get humidity ratio, dew point, vapor pressure, saturation humidity ratio, and degree of saturation.
Use humidity ratio (ΔW) for latent load and dehumidification sizing; for altitude above ~2,000 ft, correct atmospheric pressure before using W.
Inputs & Outputs
Inputs
Outputs
Formula
Calculator Formulas
All calculations assume standard atmospheric pressure:
- Imperial: P_atm = 14.696 psi
- Metric: P_atm = 101.325 kPa
Source: ASHRAE Handbook—Fundamentals (2021), Chapter 1, "Thermodynamic Wet-Bulb and Dew-Point Temperature" — liquid-water and over-ice branches.
Humidity Ratio Is Carried Dimensionless
Humidity ratio is computed as a dimensionless mass ratio — kg of water vapor per kg of dry air, numerically identical to lb/lb — using the exact constant 0.621945 = M_w / M_a = 18.015 / 28.966. Display units are applied only at the end:
g/kg = W × 1000
gr/lb = W × 7000
A single physics path serves both unit systems. Pre-scaled constants such as 621.945 and 4350 are deliberately avoided in the working equations: 4350 is a rounding of 7000 × 0.621945 = 4353.615, and carrying it makes the answer depend on which unit system happened to be selected.
Saturation Vapor Pressure (Magnus Approximation)
The phase is chosen by the temperature being evaluated — not once for the whole air state:
Over liquid water (T ≥ 0°C / 32°F):
Metric: P_sat = 0.61078 × exp(17.625 × T / (243.04 + T)) [kPa]
Imperial: P_sat = 0.08855 × exp(17.625 × Tc / (243.04 + Tc)) [psi]
Over ice (T < 0°C / 32°F):
Metric: P_sat = 0.61078 × exp(22.587 × T / (273.86 + T)) [kPa]
Imperial: P_sat = 0.08855 × exp(22.587 × Tc / (273.86 + Tc)) [psi]
where Tc = (T_°F − 32) / 1.8
Humidity Ratio from Relative Humidity
Vapor pressure:
P_v = (RH / 100) × P_sat(T_db)
Humidity ratio:
W = 0.621945 × P_v / (P_atm − P_v) [dimensionless]
P_sat(T_db) is evaluated on the branch belonging to T_db, so a below-freezing dry bulb uses the over-ice form.
Humidity Ratio from Wet-Bulb Temperature
The calculator solves the ASHRAE psychrometric equation with W and W_sat_wb dimensionless on both sides. Which branch applies is decided by the wet-bulb temperature:
Branch A — T_wb ≥ 0°C (32°F), saturation over liquid water
Imperial: W = [(1093 − 0.556 × T_wb) × W_sat_wb − 0.240 × (T_db − T_wb)]
÷ (1093 + 0.444 × T_db − T_wb) [temperatures in °F]
Metric: W = [(2501 − 2.326 × T_wb) × W_sat_wb − 1.006 × (T_db − T_wb)]
÷ (2501 + 1.86 × T_db − 4.186 × T_wb) [temperatures in °C]
Branch B — T_wb < 0°C (32°F), saturation over ice
Imperial: W = [(1220 − 0.04 × T_wb) × W_sat_wb − 0.240 × (T_db − T_wb)]
÷ (1220 + 0.444 × T_db − 0.48 × T_wb) [temperatures in °F]
Metric: W = [(2830 − 0.24 × T_wb) × W_sat_wb − 1.006 × (T_db − T_wb)]
÷ (2830 + 1.86 × T_db − 2.1 × T_wb) [temperatures in °C]
where in both branches
W_sat_wb = 0.621945 × P_sat(T_wb) / (P_atm − P_sat(T_wb))
with P_sat(T_wb) taken on the branch belonging to T_wb. The result is scaled by 7,000 for gr/lb or by 1,000 for g/kg only when it is displayed.
Each group of constants is a physical property. The numerator's first bracket — (1093 − 0.556 × T_wb) or (2501 − 2.326 × T_wb) — is the latent heat of vaporization evaluated at the wet-bulb temperature; on the ice branch, (1220 − 0.04 × T_wb) and (2830 − 0.24 × T_wb) are the latent heat of sublimation. The 0.240 BTU/lb·°F (1.006 kJ/kg·K) is the specific heat of dry air, so the second term is the sensible heat the air gives up to drive the phase change. The denominator is the enthalpy of the vapor at the dry-bulb temperature minus the enthalpy of the makeup water at the wet-bulb temperature.
The two branches do not join continuously at the freezing point, and they are not meant to: evaporating liquid water and subliming ice are different energy balances. ASHRAE notes increased uncertainty in a humidity ratio determined from a wet-bulb reading taken close to 0°C.
Phase Is Selected Per Temperature, Not Per Air State
Each temperature picks its branch independently. At T_db = +5°C with T_wb = −2°C, the humidity-ratio equation runs on the ice branch — chosen by T_wb — while P_sat(+5°C) in the relative-humidity denominator is still computed over liquid water, because that one is chosen by T_db. Forcing a single phase onto every temperature in the state is a common and avoidable error.
Humidity Ratio from Dew Point Temperature
W = 0.621945 × P_sat(T_dp) / (P_atm − P_sat(T_dp))
The dew point is the temperature at which the air becomes saturated at its current moisture content, so W equals the saturation humidity ratio at the dew point. A dew point entered below freezing is read on the liquid-water branch, matching the dew point this calculator reports — see the note under Derived Properties.
Derived Properties
Partial vapor pressure from W:
P_v = W × P_atm / (0.621945 + W) [W dimensionless]
Dew point from vapor pressure:
α = ln(P_v / 0.61078) [metric]
α = ln(P_v / 0.08855) [imperial]
T_dp = 243.04 × α / (17.625 − α) [°C]
T_dp(°F) = T_dp(°C) × 1.8 + 32
The Imperial inverse runs against the Imperial Magnus constant directly rather than converting to kPa first, which would introduce a small round-trip drift.
Below freezing this returns the dew point over supercooled liquid water, not the frost point. The frost point — the temperature at which ice actually deposits on a surface — is the higher of the two, by roughly 1°F near −5°C, about 2°F near −10°C, and close to 4°F near −20°C. The supercooled-liquid basis is used so the reported value round-trips with the dew point accepted as an input.
Degree of saturation:
μ = W / W_sat(T_db) × 100 [%]
Relative humidity (when not directly entered):
RH = P_v / P_sat(T_db) × 100 [%]
Variable Reference
| Variable | Meaning | Units |
|---|---|---|
| T_db | Dry-bulb temperature | °F / °C |
| T_wb | Wet-bulb temperature | °F / °C |
| T_dp | Dew point temperature | °F / °C |
| RH | Relative humidity | % |
| W | Humidity ratio (dimensionless internally) | gr/lb / g/kg |
| W_sat | Saturation humidity ratio at T_db | gr/lb / g/kg |
| W_sat_wb | Saturation humidity ratio at T_wb | dimensionless |
| P_v | Partial vapor pressure | psi / kPa |
| P_sat | Saturation vapor pressure | psi / kPa |
| μ | Degree of saturation (W / W_sat) | % |
| P_atm | Standard atmospheric pressure | 14.696 psi / 101.325 kPa |
What Is Humidity Ratio?
Humidity ratio (W) is the mass of water vapor contained in a given mass of dry air. In Imperial units it is expressed in grains of moisture per pound of dry air (gr/lb), where 7,000 grains equals one pound. In SI units it is expressed in grams of moisture per kilogram of dry air (g/kg). The dimensionless form (lb/lb or kg/kg) is used in psychrometric equations.
Humidity ratio is an absolute moisture measurement — it does not change with temperature unless moisture is physically added or removed. This distinguishes it from relative humidity, which varies with temperature even when the actual moisture content stays constant.
Why Humidity Ratio Matters in HVAC
Humidity ratio is the basis for every latent load calculation in HVAC engineering. The latent cooling load on a coil equals the mass flow rate of air multiplied by the difference in humidity ratio between entering and leaving conditions, multiplied by the latent heat of vaporization:
Q_latent = ṁ × ΔW × h_fg
In Imperial units, the standard latent load formula is:
Q_latent = 0.68 × CFM × ΔW (gr/lb)
where 0.68 = 60 min/hr × 0.075 lb/ft³ × 1076 BTU/lb ÷ 7000 gr/lb.
Without accurate humidity ratio values, latent loads cannot be calculated, coil selections will be wrong, and dehumidification systems will be improperly sized.
Humidity Ratio vs. Relative Humidity
Relative humidity (RH) is the ratio of the actual vapor pressure to the saturation vapor pressure at the same temperature. It tells you how close the air is to saturation, but it does not tell you how much moisture the air actually contains.
For example, air at 75°F and 50% RH contains approximately 65 gr/lb of moisture. If that same air is cooled to 55°F without removing moisture, its relative humidity rises to approximately 100% — but the humidity ratio remains 65 gr/lb. The moisture content did not change; only the air's capacity to hold moisture changed.
This is why HVAC engineers use humidity ratio for load calculations and mixing problems, and use relative humidity primarily for comfort assessment and control setpoints.
Degree of Saturation vs. Relative Humidity
Degree of saturation (μ) is the ratio of the actual humidity ratio to the saturation humidity ratio at the same dry-bulb temperature: μ = W / W_sat. It is numerically close to relative humidity but not identical. The difference arises because RH is based on vapor pressures while μ is based on humidity ratios, and the relationship between vapor pressure and humidity ratio is not perfectly linear due to the (P_atm − P_v) term in the denominator. At typical HVAC conditions the difference is small (usually less than 2%), but at high humidity ratios the divergence becomes significant.
Key Facts
- Humidity ratio remains constant through any sensible heating or cooling process. Only processes that add or remove moisture — such as dehumidification, humidification, or mixing with a different air stream — change the humidity ratio.
- In Imperial units, 7,000 grains equals 1 pound. A humidity ratio of 70 gr/lb means the air contains 0.01 lb of water vapor per pound of dry air.
- The standard Imperial latent load formula Q = 0.68 × CFM × ΔW requires ΔW in gr/lb. Using ΔW in lb/lb without the 7,000 multiplier produces a result that is 7,000 times too small.
- At standard conditions (75°F, 50% RH, sea level), humidity ratio is approximately 65 gr/lb (9.3 g/kg). This is a useful benchmark for quick sanity checks.
- Humidity ratio at saturation increases exponentially with temperature. At 60°F saturation W is about 77 gr/lb; at 90°F it is about 218 gr/lb — nearly three times higher for a 30°F increase.
- The dew point temperature is the temperature at which the air's humidity ratio equals the saturation humidity ratio. Cooling air below its dew point causes condensation.
Applications
- Latent cooling load calculation — Q_latent = 0.68 × CFM × ΔW (Imperial) or ṁ × ΔW × h_fg (Metric)
- Dehumidification system sizing — required moisture removal rate in lb/hr or kg/hr from airflow × ΔW
- Air mixing calculations — mixed air W = (W₁ × ṁ₁ + W₂ × ṁ₂) / (ṁ₁ + ṁ₂)
- Cooling coil apparatus dew point estimation — the coil surface temperature at which the supply air humidity ratio is achieved
- Energy recovery ventilation latent effectiveness — η_latent = ΔW_actual / ΔW_max
- Indoor air quality assessment — verifying that indoor humidity ratio stays within ASHRAE 55 comfort limits
- Desiccant wheel sizing — moisture removal capacity depends on the humidity ratio difference across the wheel
- Condensation risk analysis — comparing surface temperature to dew point derived from humidity ratio
Example Calculation
Imperial Example
Given: T_db = 75°F, RH = 50%
Step 1 — Saturation Pressure (75°F is above freezing, liquid-water branch):
Tc = (75 − 32) / 1.8 = 23.89°C
P_sat = 0.08855 × exp(17.625 × 23.89 / (243.04 + 23.89))
P_sat = 0.08855 × exp(1.5774) = 0.08855 × 4.8421 = 0.4288 psi
Step 2 — Vapor Pressure:
P_v = 0.50 × 0.4288 = 0.2144 psi
Step 3 — Humidity Ratio (dimensionless first, display units last):
W = 0.621945 × 0.2144 / (14.696 − 0.2144)
W = 0.133344 / 14.4816 = 0.0092073 lb/lb
W = 0.0092073 × 7000 = 64.45 gr/lb
Step 4 — Dew Point:
α = ln(0.2144 / 0.08855) = ln(2.4213) = 0.8842
T_dp(°C) = 243.04 × 0.8842 / (17.625 − 0.8842) = 214.90 / 16.7408 = 12.84°C
T_dp(°F) = 12.84 × 1.8 + 32 = 55.11°F
Step 5 — Saturation Humidity Ratio at T_db:
W_sat = 0.621945 × 0.4288 / (14.696 − 0.4288) = 0.0186912 lb/lb
W_sat = 0.0186912 × 7000 = 130.84 gr/lb
Step 6 — Degree of Saturation:
μ = 64.45 / 130.84 × 100 = 49.26%
Metric Example
Given: T_db = 24°C, RH = 50%
Step 1 — Saturation Pressure:
P_sat = 0.61078 × exp(17.625 × 24 / (243.04 + 24))
P_sat = 0.61078 × exp(1.5840) = 0.61078 × 4.8746 = 2.9773 kPa
Step 2 — Vapor Pressure:
P_v = 0.50 × 2.9773 = 1.4886 kPa
Step 3 — Humidity Ratio:
W = 0.621945 × 1.4886 / (101.325 − 1.4886)
W = 0.925822 / 99.8364 = 0.0092733 kg/kg
W = 0.0092733 × 1000 = 9.27 g/kg
Step 4 — Dew Point:
α = ln(1.4886 / 0.61078) = ln(2.4372) = 0.8909
T_dp = 243.04 × 0.8909 / (17.625 − 0.8909) = 216.53 / 16.7341 = 12.94°C
Step 5 — Saturation Humidity Ratio at T_db:
W_sat = 0.621945 × 2.9773 / (101.325 − 2.9773) = 0.0188282 kg/kg = 18.83 g/kg
Step 6 — Degree of Saturation:
μ = 9.27 / 18.83 × 100 = 49.25%
Wet-Bulb Example (Imperial)
Given: T_db = 75°F, T_wb = 62.6°F — the same air state as the Imperial example above, measured with a sling psychrometer instead of a hygrometer.
Step 1 — Saturation Humidity Ratio at the Wet-Bulb Temperature. T_wb is above freezing, so Branch A applies and P_sat(T_wb) is taken over liquid water:
Tc = (62.6 − 32) / 1.8 = 17.00°C
P_sat(T_wb) = 0.08855 × exp(17.625 × 17.00 / (243.04 + 17.00))
P_sat(T_wb) = 0.08855 × exp(1.1522) = 0.08855 × 3.1652 = 0.2803 psi
W_sat_wb = 0.621945 × 0.2803 / (14.696 − 0.2803) = 0.012092 lb/lb (84.65 gr/lb)
Step 2 — Wet-Bulb Depression:
T_db − T_wb = 75 − 62.6 = 12.4°F
Step 3 — ASHRAE Psychrometric Equation, Branch A:
Numerator = (1093 − 0.556 × 62.6) × 0.012092 − 0.240 × 12.4
= 1058.19 × 0.012092 − 2.976
= 12.7955 − 2.976 = 9.8195
Denominator = 1093 + 0.444 × 75 − 62.6 = 1093 + 33.3 − 62.6 = 1063.70
W = 9.8195 / 1063.70 = 0.0092319 lb/lb
W = 0.0092319 × 7000 = 64.62 gr/lb
Step 4 — Cross-Check Against the Other Two Routes:
Relative humidity route (75°F, 50% RH): 64.45 gr/lb
Wet-bulb route (75°F db, 62.6°F wb): 64.62 gr/lb
Dew point route (55.1°F dew point): 64.44 gr/lb
All three inputs describe one air state, and all three land within 0.3% of each other. That agreement is the check worth running whenever a wet-bulb result looks suspect: if the routes disagree by more than about 1%, the instrument reading or the entered temperature is the problem, not the calculation.
Wet-Bulb Example (Metric)
Given: T_db = 24°C, T_wb = 17.1°C
P_sat(T_wb) = 0.61078 × exp(17.625 × 17.1 / (243.04 + 17.1))
P_sat(T_wb) = 0.61078 × exp(1.1586) = 1.9455 kPa
W_sat_wb = 0.621945 × 1.9455 / (101.325 − 1.9455) = 0.012176 kg/kg
Numerator = (2501 − 2.326 × 17.1) × 0.012176 − 1.006 × (24 − 17.1)
= 2461.23 × 0.012176 − 6.9414
= 29.9679 − 6.9414 = 23.0265
Denominator = 2501 + 1.86 × 24 − 4.186 × 17.1 = 2501 + 44.64 − 71.58 = 2474.06
W = 23.0265 / 2474.06 = 0.0093070 kg/kg = 9.31 g/kg
The relative humidity route at 24°C and 50% RH gives 9.27 g/kg and the dew point route at 12.94°C gives 9.27 g/kg, so all three agree within 0.4%.
Sub-Freezing Example — the Ice Branch (Metric)
Given: T_db = −5°C, T_wb = −8°C
Step 1 — Saturation Pressure at the Wet Bulb. T_wb is below freezing, so P_sat(T_wb) is taken over ice:
P_sat(T_wb) = 0.61078 × exp(22.587 × (−8) / (273.86 − 8))
= 0.61078 × exp(−0.67958) = 0.30953 kPa
W_sat_wb = 0.621945 × 0.30953 / (101.325 − 0.30953) = 0.0019058 kg/kg
Step 2 — ASHRAE Psychrometric Equation, Branch B (selected by T_wb, not by T_db):
Numerator = (2830 − 0.24 × (−8)) × 0.0019058 − 1.006 × (−5 − (−8))
= 2831.92 × 0.0019058 − 3.018
= 5.3971 − 3.018 = 2.3791
Denominator = 2830 + 1.86 × (−5) − 2.1 × (−8) = 2830 − 9.30 + 16.80 = 2837.50
W = 2.3791 / 2837.50 = 0.00083845 kg/kg = 0.838 g/kg
Step 3 — Derived Properties. Here the dry bulb is also below freezing, so P_sat(T_db) is taken over ice as well — but note that this is decided by T_db on its own, not inherited from the wet bulb:
P_v = 0.00083845 × 101.325 / (0.621945 + 0.00083845) = 0.1364 kPa
P_sat(T_db) = 0.61078 × exp(22.587 × (−5) / (273.86 − 5)) = 0.40129 kPa
RH = 0.1364 / 0.40129 × 100 = 33.99%
W_sat = 0.621945 × 0.40129 / (101.325 − 0.40129) = 2.473 g/kg
μ = 0.838 / 2.473 × 100 = 33.90%
T_dp = −19.05°C
The reported dew point of −19.05°C is the supercooled-liquid value. For the same air the frost point — where ice actually deposits — is −17.04°C, about 2°C higher. If the question is when frost will form on a surface, the frost point is the number that matters.
Had this state been entered with a dry bulb above freezing and a wet bulb below it, Branch B would still govern the humidity-ratio equation, while P_sat(T_db) would switch to the liquid-water form. The two choices are made separately.
Standards & References
- ASHRAE Handbook — Fundamentals (2021), Ch. 1 Psychrometrics — Primary reference for psychrometric definitions, humidity ratio formulations, and moist-air property calculations
- ASHRAE Standard 55-2023: Thermal Environmental Conditions for Human Occupancy — Defines acceptable humidity limits for comfort (upper limit approximately 0.012 kg/kg or 84 gr/lb)
- ASHRAE Standard 62.1-2022: Ventilation and Acceptable Indoor Air Quality — Outdoor air humidity ratio affects ventilation latent loads
- Magnus Formula (Alduchov & Eskridge, 1996) — Saturation vapor pressure approximation: P_sat = 0.61078 × exp(17.625T / (243.04 + T))
- ASHRAE Handbook — HVAC Systems and Equipment (2020), Chapter 23 — Dehumidification system sizing based on humidity ratio difference
Limitations
- All calculations assume standard atmospheric pressure: 14.696 psi (101.325 kPa). At 5,000 ft elevation, atmospheric pressure drops to approximately 12.23 psi, increasing humidity ratio by roughly 20% for the same vapor pressure.
- The wet-bulb route solves the full ASHRAE psychrometric equation, in which the effective depression coefficient is not a constant: it depends on the dry-bulb temperature, the wet-bulb temperature, and the saturation humidity ratio at the wet bulb all at once. Fixed gr/lb-per-°F or g/kg-per-°C coefficients quoted from a worked example reproduce that equation only near the conditions they were derived at, and drift at large wet-bulb depressions and at the edges of the temperature range. This calculator evaluates the equation itself rather than any linearization of it.
- Both branches of the wet-bulb equation are implemented. A wet-bulb temperature at or above 32°F (0°C) uses the liquid-water coefficients; below that, where the wick freezes, the calculation switches to the over-ice coefficients and the latent heat of sublimation. The branch is selected by the wet-bulb temperature alone, while the saturation pressure at the dry bulb follows the dry bulb. The two branches are not continuous across the freezing point because they rest on different energy balances, and ASHRAE notes increased uncertainty in a humidity ratio determined from a wet-bulb reading taken close to 0°C.
- The Magnus approximation for saturation vapor pressure is accurate to within ±0.4% over the range −40°C to 50°C. Outside this range, use the more precise Hyland-Wexler or IAPWS-IF97 formulations.
- This calculator does not account for the effect of dissolved salts or contaminants on vapor pressure. For industrial processes involving hygroscopic materials, additional corrections may be needed.
- Degree of saturation (μ) and relative humidity (RH) diverge at high humidity ratios. At W > 100 g/kg, the difference can exceed 5%.
Common Mistakes to Avoid
- Confusing humidity ratio units: gr/lb vs. lb/lb. The ASHRAE enthalpy formula uses lb/lb (W / 7000), while the latent load formula 0.68 × CFM × ΔW uses gr/lb directly. Mixing these up produces errors of 7,000×.
- Using relative humidity instead of humidity ratio for latent load calculations. RH changes with temperature; W does not. Latent load depends on the actual moisture difference (ΔW), not the RH difference.
- Assuming humidity ratio and specific humidity are identical. Specific humidity is the mass of vapor per unit mass of moist air (W / (1 + W)), while humidity ratio is per unit mass of dry air. The difference is small at low moisture levels but grows at high humidity.
- Applying one phase to every temperature in the air state. Below freezing the equation branch and P_sat(T_wb) are selected by the wet bulb, while P_sat(T_db) in the relative-humidity and degree-of-saturation denominators is selected by the dry bulb. At T_db = +5°C with T_wb = −2°C the humidity-ratio equation runs over ice while P_sat(+5°C) is still computed over liquid water. Forcing a single phase onto the whole state shifts relative humidity by several percent.
- Reading a below-freezing dew point as a frost point. This calculator reports the dew point over supercooled liquid water on both sides of 0°C, which is the basis that round-trips with the dew point it accepts as input. Ice deposits on a surface at the frost point, which is higher — by roughly 1°F near −5°C and close to 4°F near −20°C. Sizing a defrost strategy against the dew point understates when frost appears.
- Applying sea-level formulas at high altitude without correction. At 5,000 ft elevation, atmospheric pressure is approximately 12.23 psi instead of 14.696 psi, which increases humidity ratio by roughly 20% for the same vapor pressure.
Frequently Asked Questions
What is the difference between humidity ratio and specific humidity?
How do I convert between gr/lb and g/kg?
Why does humidity ratio stay constant during sensible heating?
What humidity ratio corresponds to comfortable indoor conditions?
How does altitude affect humidity ratio calculations?
Can humidity ratio be negative?
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Calculate
Dry-bulb temperature of the air
Relative humidity of the air (0–100%)