Daily device use can be measured in hours or in dollars, and the two screen time calculator and digital device usage cost calculator each cover one side. The screen time calculator adds up device hours, weights nighttime use, and returns an impact score with break and age-group suggestions. The device usage cost calculator turns the same kind of device list into a monthly cost by combining electricity, depreciation, maintenance, and recurring fees. The device-usage-cost article puts it directly: “If your focus is hours and habits, use the screen time calculator.”
What each calculator does
The screen time calculator takes an age group, primary use, computer or laptop hours, smartphone or tablet hours, TV or gaming hours, and a nighttime-use figure for the part of the day within two hours of bedtime. Total screen time is the direct sum of the three device categories, validated so the total is 24 hours or less and nighttime use does not exceed the total. The impact score weights computer hours by 1.0, smartphone hours by 1.2, TV or gaming hours by 0.8, and adds nighttime hours at 1.5; scores at or below 50 are labeled low risk and above 50 moderate. It then suggests device-specific breaks — every 2 hours on computers, every 30 minutes on phones — adds the 20-20-20 rule when the total passes 4 hours, and gives age-based hour prompts. Its worked example: 4 computer + 2 smartphone + 2 TV hours with 1 nighttime hour gives 8 hours and an impact score of 9.5.
The digital device usage cost calculator takes an electricity rate in dollars per kWh plus up to 20 devices, each with hours per day, power in watts, purchase price, lifespan in years, monthly fees, and yearly maintenance. Per device, daily energy is watts × hours ÷ 1,000, monthly power cost is that figure × 30 × the rate, depreciation spreads the purchase price over lifespan in months, and maintenance is the yearly amount divided by 12. The device total is power + depreciation + maintenance + fees, and the page sums all devices. Its worked example totals a 65 W laptop at $35.21 per month and a game console at $23.80 per month, displaying $59.00.
Side-by-side
| Screen time calculator | Digital device usage cost calculator | |
|---|---|---|
| Primary question | How much time and what pattern? | How much does it cost per month? |
| Inputs | Device hours, nighttime hours, age group, primary use | Electricity rate; per-device hours, watts, price, lifespan, fees, maintenance |
| Main output | Total hours, impact score, risk label, break and age suggestions | Total monthly cost in dollars with per-device breakdowns |
| Weighting | Phone 1.2×, TV 0.8×, nighttime +1.5× | Power, depreciation, maintenance, and fees summed per device |
| Validation | Total ≤ 24 hours; nighttime ≤ total | At least one device; positive lifespan; numeric fields required |
| Worked example | 4 + 2 + 2 hours → 8 hours, score 9.5 low risk | Laptop + console → $59.00 per month |
| Other tools it points to | Digital wellbeing, screen time cost, sleep, work-life balance | Electricity cost, screen time cost, budget, digital storage needs |
When to use which
Use the screen time calculator when you want a personal audit: a family discussion, a student schedule, or a work-setup review. Its article distinguishes it from the cost calculators explicitly — it is different from the digital wellbeing calculator’s habit scores and from the screen time cost calculator’s electricity-and-depreciation estimates. The output is a pattern you can act on: reduce the largest device category, cut nighttime scrolling, or protect bedtime.
Use the device usage cost calculator when the question is “what does this device or setup cost me each month?” It is the tool to compare a home office, gaming setup, or always-on router-and-modem list, and its article recommends the electricity cost calculator when only appliance-style power math is needed, and the screen time calculator when hours and habits are the focus. The power row follows the DOE-style wattage-hours-price method, while depreciation and fees capture why a low-watt laptop can still cost more per month than a higher-watt device.
Limits and disclaimer
The screen time calculator is a habit-estimation tool, not a medical assessment: its score is a page-defined heuristic, its high-risk band above 75 is unreachable for valid 24-hour-or-less inputs, and the article warns it does not diagnose eye strain, sleep trouble, or related conditions. Do not double-count the same hour in two device fields or enter weekly hours as daily. The device usage cost calculator is a planning estimate that does not measure standby power separately, seasonal use, time-of-use rates, resale value, or shared family use; the article warns not to enter watts as kW and not to treat purchase price as a monthly fee, since depreciation already spreads it. Both pages recommend professional guidance or measured data (e.g. a plug-in power meter) when consequences are significant.