🧮 常用计算器Everyday Calculators
科学计算器Scientific Calculator
功能齐全的在线科学计算器：三角函数（角度/弧度）、对数、幂、开方、阶乘、括号、记忆和历史，支持键盘输入，安全解析不使用 eval。A full scientific calculator: trig (deg/rad), logs, powers, roots, factorial, parentheses, memory and history, with keyboard support and a safe parser (no eval).
平方英尺面积计算器Square Footage Calculator
按长宽计算房间或地块的平方英尺、平方米和平方码面积，支持矩形、圆形、三角形，可估算总价。Work out square feet, square meters and square yards for rectangles, circles and triangles, with optional cost per square foot.
屋顶材料计算器Roofing Calculator
根据房屋长宽、屋顶坡度和挑檐估算屋顶面积、屋面“方”（100 平方英尺）数和沥青瓦捆数。Estimate roof area, roofing squares (100 sq ft) and shingle bundles from house size, pitch and overhang.
瓷砖用量计算器Tile Calculator
按铺贴面积、瓷砖尺寸、砖缝和损耗率计算需要多少块瓷砖和多少箱。Calculate how many tiles and boxes you need from the area, tile size, grout gap and waste allowance.
混凝土用量计算器Concrete Calculator
计算楼板、地坪或圆柱所需混凝土体积（立方米、立方码），以及 80 磅/60 磅预拌袋数。Work out concrete volume for slabs, footings or round columns in m³ and cubic yards, plus 80 lb / 60 lb premix bags.
覆盖物用量计算器Mulch Calculator
按花坛面积和铺设厚度计算树皮/覆盖物需要多少立方码、立方米和袋数。Find how much mulch you need in cubic yards, cubic meters and bags from bed size and depth.
油漆用量计算器Paint Calculator
根据房间尺寸、门窗面积、涂刷遍数和油漆覆盖率计算需要多少加仑或升油漆。Estimate gallons or liters of paint from room size, doors and windows, number of coats and coverage.
立方码计算器Cubic Yard Calculator
输入长、宽、深度（可用不同单位）计算立方码、立方英尺和立方米，适合土方、碎石和覆盖物。Convert length × width × depth in mixed units to cubic yards, cubic feet and cubic meters for soil, gravel or mulch.
碎石用量计算器Gravel Calculator
按面积和铺设厚度计算碎石体积，并按密度换算成吨数（公吨和美吨）。Calculate gravel volume from area and depth, then its weight in metric tonnes and US tons using material density.
楼梯计算器Stair Calculator
根据总高度、最大踏步高和踏面宽度计算台阶数、实际踢面高、总水平长度、斜梁长度和坡度角。Work out the number of steps, actual riser height, total run, stringer length and angle from the total rise.
板英尺计算器Board Foot Calculator
按厚度、宽度、长度和数量计算木材板英尺（BF）数和总价，并换算为立方米。Calculate lumber board feet from thickness, width, length and quantity, with total cost and cubic meters.
屋顶坡度计算器Roof Pitch Calculator
由升高和水平跨度计算屋顶坡度（x/12）、角度、百分比坡度和坡度系数，也可由角度反算。Find roof pitch (x/12), angle, percent grade and multiplier from rise and run, or from an angle.
地板用量计算器Flooring Calculator
按房间面积、损耗率和每箱覆盖面积计算需要多少箱木地板/复合地板，并估算费用。Work out how many boxes of laminate, vinyl or hardwood flooring you need, with waste and cost.
成绩计算器Grade Calculator
按各项作业/考试的得分与权重计算加权总评成绩，并换算成美式字母等级（A+ 到 F）。Weighted course grade from assignment and exam scores and weights, with the US letter grade (A+ to F).
GPA 绩点计算器GPA Calculator
按课程成绩与学分计算平均学分绩点（GPA），支持美国字母等级、百分制标准 4.0 和北大 4.0 公式。Calculate GPA from course grades and credits using US letter grades, the standard 4.0 percentage scale or the Peking University 4.0 formula.
期末成绩计算器Final Grade Calculator
已知当前成绩和期末考试所占权重，计算想达到目标总评需要期末考多少分。Find the score you need on the final exam to reach a target course grade, given your current grade and the final's weight.
油耗计算器Fuel Consumption Calculator
输入行驶里程和加油量计算实际油耗（L/100km、km/L、美制和英制 MPG），可按油价算出每公里成本。Work out real fuel consumption from distance driven and fuel used — L/100 km, km/L, US and UK MPG — and the cost per km with a fuel price.
轮胎尺寸计算器Tire Size Calculator
解析 205/55R16 这类轮胎规格，计算胎壁高度、外直径、周长和每公里转数，并对比两种轮胎的速度表误差。Decode tire sizes like 205/55R16 into sidewall height, overall diameter, circumference and revolutions per km/mile, and compare two sizes for speedometer error.
英尺英寸计算器Feet and Inches Calculator
英尺和英寸的加减乘除（如 5'8" + 3'6"），结果以英尺-英寸（精确到 1/16 英寸）、总英寸和厘米显示。Add, subtract, multiply or divide feet and inches (e.g. 5'8" + 3'6"), with results in feet-inches to 1/16 in, total inches and centimeters.
戒指尺寸计算器Ring Size Calculator
由戒指内径、手指周长或美码换算美国/加拿大、英国/澳洲、欧洲（ISO）戒指尺码。Convert ring inner diameter, finger circumference or US size to US/Canada, UK/Australia and European (ISO) ring sizes.
金属重量计算器Metal Weight Calculator
按形状尺寸和材料密度计算钢板、圆钢、方钢、六角钢、钢管和扁钢的重量，支持碳钢、不锈钢、铝、铜、黄铜、钛等，可输入数量求总重。Calculate the weight of metal plate, round bar, square bar, hex bar, tube and flat bar from its dimensions and density — carbon steel, stainless, aluminium, copper, brass, titanium and more — with a quantity for the total.
自行车尺寸计算器（车架尺寸）Bike Size Calculator (Frame Size)
根据腿内侧长（裆高）计算公路车、山地车、城市/旅行车的推荐车架尺寸和座垫高度，儿童车按腿长推荐轮径；只知道身高时也可估算。Find your road, mountain and city/trekking bike frame size and saddle height from your inseam — or estimate it from height — with a wheel size for kids' bikes.
钢筋用量计算器Rebar Calculator
按板面尺寸、钢筋间距和保护层计算双向钢筋网需要的根数、总长度、按定尺长度折算的支数和总重量，支持美国 #3–#8 和公制 8–25 mm 钢筋。Work out a two-way rebar grid for a slab: bars each way, total length, stock lengths to buy and total weight from the slab size, spacing and edge cover, for US #3–#8 or metric 8–25 mm bars.
砖块用量计算器Brick Calculator
按墙面长度、高度、门窗洞口面积、砖块尺寸和灰缝厚度计算需要多少块砖，内置美国标准砖、英国砖和中国标准砖（240×115×53 mm）尺寸，可加损耗。Find how many bricks a wall needs from its length, height, openings, brick size and mortar joint, with US modular, UK standard and Chinese standard (240×115×53 mm) bricks and a waste allowance.
沥青用量计算器Asphalt Calculator
按铺设面积和压实厚度计算热拌沥青混合料的体积和吨数（默认密度 145 lb/ft³ ≈ 2.32 t/m³），可输入单价估算材料费，适合车道、停车场铺设。Estimate hot-mix asphalt volume and tonnage for a driveway or parking lot from the area and compacted thickness (default density 145 lb/ft³ ≈ 2.32 t/m³), with an optional price per ton.
立方英尺计算器Cubic Feet Calculator
按长、宽、高（可分别选择英寸、英尺、码、厘米、米）计算箱体、房间或圆柱体的体积，结果同时给出立方英尺、立方米、立方码、升和美制加仑，可输入件数求总体积。Calculate volume in cubic feet for a box, room or cylinder from its dimensions in inches, feet, yards, centimetres or metres, with cubic metres, cubic yards, litres and US gallons, and a count for the total.
地毯用量计算器Carpet Calculator
按房间长宽、地毯卷宽（如 12 英尺或 4 米）和损耗计算需要购买的地毯面积和卷长，并估算地毯、衬垫和安装费用。Work out how much carpet to buy from the room size, roll width (such as 12 ft or 4 m) and waste, with the length to cut from the roll and the cost of carpet, pad and installation.
围栏材料计算器Fence Calculator
按围栏总长度、立柱间距和门的数量计算需要的立柱、横杆、栅板数量和立柱混凝土袋数，适合木栅栏和尖桩篱笆。Estimate fence materials — posts, rails, pickets and concrete bags for the posts — from the total length, post spacing and number of gates, for wood privacy and picket fences.
墙纸用量计算器Wallpaper Calculator
按房间周长、墙高、墙纸卷的宽度和长度以及花纹回位（对花）计算需要几卷墙纸：先算每卷能裁几幅，再算整个房间需要几幅，扣除门窗宽度，比单纯按面积估算更准确。Work out how many rolls of wallpaper a room needs from the wall widths, height, roll width and length and pattern repeat. It counts how many drops each roll gives and how many drops the room needs, less doors and windows — more accurate than dividing areas.
货运等级（NMFC 密度等级）计算器Freight Class Calculator
按货物尺寸和重量计算密度（磅/立方英尺），并按 NMFC 2025 年 7 月起施行的 13 档密度分级表确定 LTL 零担货运等级（50–400），支持英寸/磅和厘米/千克，可输入多件。Calculate shipment density in lb/ft³ from the dimensions and weight, and find the LTL freight class (50–400) on the 13-tier NMFC density scale in effect from July 2025, in inches and pounds or centimetres and kilograms, for several identical pieces.
菜谱用量换算器（按份数缩放）Recipe Scaler
把菜谱按新的份数或倍数等比例放大或缩小：粘贴配料清单（每行一种，如“2 1/2 杯 面粉”“200g butter”），自动换算每种配料的用量，支持分数、带分数、小数和范围（如 2–3）。Scale a recipe up or down to a new number of servings or by any factor: paste the ingredient list, one per line (such as "2 1/2 cups flour" or "200 g butter"), and every amount is recalculated — fractions, mixed numbers, decimals and ranges like 2–3 included.
混凝土方量计算器（板、柱、数量、损耗、袋数）Concrete Volume Calculator (Slab, Column, Quantity, Waste, Bags)
计算浇筑所需混凝土：长方形板/基础（长 × 宽 × 厚）或圆柱（直径 × 高），可填数量和损耗率，结果给出立方米、立方码、立方英尺，以及预拌干混料袋数（25 kg、40 kg、60 lb、80 lb）。本地处理。Concrete needed for a rectangular slab or footing (length × width × thickness) or a round column (diameter × height), with quantity and waste allowance. Results in cubic metres, cubic yards and cubic feet, plus premix bag counts (25 kg, 40 kg, 60 lb, 80 lb). Processed locally.
路基材料体积Road Base Calculator
长*宽*厚 → 体积（m3）。本地处理。可设置「长 m」、「宽 m」、「厚 m」。Length * width * depth → volume (m3). Processed locally. Settings: Length m, Width m, Depth m.
木甲板染色剂用量Deck Stain Calculator
用量 = 面积 × 涂刷遍数 / 每升（或每加仑）覆盖面积，并按容器规格取整。本地处理。可设置「甲板面积 m²」、「遍数」、「每升覆盖 m²」、「每桶升数」。Amount = area × coats / coverage per litre (or gallon), rounded up to whole containers. Processed locally. Settings: Deck area m², Coats, Coverage per litre m², Litres per can.
石膏板用量Drywall Calculator
墙面积（减去门窗）÷ 单张面积 × (1 + 损耗)，向上取整。本地处理。可设置「墙总长 m」、「墙高 m」、「门窗面积 m²」、「板宽 m」、「板高 m」。Wall area (minus openings) ÷ sheet area × (1 + waste), rounded up. Processed locally. Settings: Total wall length m, Wall height m, Openings m², Sheet width m, Sheet height m.
手套尺码Glove Size Calculator
量手掌最宽处（不含拇指）的周长，换算成英寸即手套尺码，并给出 XS-XXL 参考。本地处理。Measure around the widest part of the palm (excluding the thumb); in inches that is the glove size, with an XS-XXL guide. Processed locally.
停车位配比Parking Ratio Calculator
停车配比 = 车位数 ÷ 建筑面积 × 1000（每千平方英尺车位数），或每 100 m² 车位数；也可由目标配比反求所需车位。本地处理。Parking ratio = spaces ÷ floor area × 1,000 (spaces per 1,000 sq ft), or per 100 m²; or work out the spaces needed for a target ratio. Processed locally.
泳池加盐量（盐水泳池）Pool Salt Calculator
加盐量（磅）= 加仑数 × 8.34 × (目标 ppm - 当前 ppm) ÷ 1,000,000；同时给出千克和 40 磅袋数。本地处理。Salt (lb) = gallons × 8.34 × (target ppm - current ppm) ÷ 1,000,000, also in kilograms and 40-lb bags. Processed locally.
被子包边布用量Quilt Binding Calculator
包边总长 = 被子周长 + 预留（默认 12 英寸），按布幅可用宽度裁成若干条，算出需要的布条数和布料长度。本地处理。Binding length = quilt perimeter + extra (12 in by default); strips cut across the usable fabric width give the strip count and fabric length needed. Processed locally.
再订货点 ROPReorder Point Calculator
再订货点 = 日均用量 × 交货周期（天）+ 安全库存；也可按"最大日用量 × 最长交货期 - 平均日用量 × 平均交货期"估算安全库存。本地处理。Reorder point = average daily usage × lead time (days) + safety stock; safety stock can be estimated as max daily usage × max lead time - average usage × average lead time. Processed locally.
地毯尺寸Rug Size Calculator
按房间尺寸和四周留边（常见 30-60 cm）算出合适的地毯尺寸，并推荐不超过它的最大常见规格。本地处理。From the room size and the floor border to leave (typically 30-60 cm), get the ideal rug size and the largest common size that fits. Processed locally.
洗澡费用（水费 + 热水能耗）Shower Cost Calculator
用水量 = 时长 × 流量；加热能耗 = 用水量 × 4.186 kJ/(kg·°C) × 温升 ÷ 热水器效率。合计每次、每月水费和能源费。本地处理。Water = duration × flow; heating energy = water × 4.186 kJ/(kg·°C) × temperature rise ÷ heater efficiency. Adds up water and energy cost per shower and per month. Processed locally.
电视挂墙高度TV Mounting Height Calculator
让屏幕中心与坐姿视线齐平（默认 107 cm / 42 in）：按尺寸和比例算出屏幕高度，以及屏幕中心、下沿和上沿离地高度，并给出建议观看距离。本地处理。Put the screen centre at seated eye level (107 cm / 42 in by default): from the size and aspect ratio, get the screen height and the centre, bottom and top heights, plus a suggested viewing distance. Processed locally.
LED 灯节电计算LED Savings Calculator
把旧灯泡换成 LED：每年节电 = (旧功率 - LED 功率) × 数量 × 每天小时数 × 365 ÷ 1000，并计算节省电费和回本时间。本地处理。Switching to LED: energy saved per year = (old watts - LED watts) × bulbs × hours per day × 365 ÷ 1,000, with money saved and payback time. Processed locally.
高中 GPA（加权 / 不加权）High School GPA Calculator (Weighted & Unweighted)
每行一门课：等级 学分 类型（regular / honors / AP，类型可省略），按 4.0 制计算不加权 GPA，并按荣誉课 +0.5、AP/IB +1.0 计算加权 GPA。本地处理。One course per line: grade credits type (regular / honors / AP; type optional). Gives the unweighted GPA on the 4.0 scale and the weighted GPA with +0.5 for honors and +1.0 for AP/IB. Processed locally.
PPI / 像素密度计算Pixels Per Inch (PPI) Calculator
PPI = 像素 ÷ 英寸；也可由像素与 PPI 反推印刷尺寸。可设置「计算」、「像素（边长）」、「英寸（边长）」、「PPI」。PPI = pixels ÷ inches; or print size from pixels and PPI. Settings: Calculate, Pixels (edge), Inches (edge), PPI.
克转杯（烹饪）Grams to Cups (Cooking)
按食材密度把克换成美制杯（1 cup ≈ 240 ml）。可设置「克」、「食材」、「自定义 g/杯」。Grams → US cups by ingredient density (1 cup ≈ 240 ml). Settings: Grams, Ingredient, Custom g per cup.
杯转克（烹饪）Cups to Grams (Cooking)
按常见食材密度把美制杯换成克（默认 1 cup ≈ 240 ml 水重）。面粉、糖、黄油等预置密度仅供烹饪估算；品牌与过筛方式会差 10% 以上，可用「自定义 g/杯」。US cups → grams using common cooking densities (default cup ≈ 240 ml of water). Presets for flour, sugar, butter, etc. are kitchen estimates - brands and packing can differ by 10%+, so use Custom g/cup when you care.
杯转磅（烹饪）Cup to Pound (Cooking)
按食材密度把美制杯换成磅。可设置「杯」、「食材」、「自定义 g/杯」。US cups → pounds by ingredient density. Settings: Cups, Ingredient, Custom g per cup.
加仑转千克（水）Gal to kg (Water)
美制加仑水的质量（ρ ≈ 0.998 kg/L @20°C，按 1 gal = 3.785411784 L）。可设置「加仑 (US)」、「密度 kg/L」。Mass of US gallons of water (ρ ≈ 0.998 kg/L @20°C; 1 gal = 3.785411784 L). Settings: Gallons (US), Density kg/L.
加仑转磅（水）Gal to lb (Water)
美制加仑水的磅数。可设置「加仑 (US)」、「密度 kg/L」。Pounds of US gallons of water. Settings: Gallons (US), Density kg/L.
千克转加仑（水）Kg to Gal (Water)
水的质量换美制加仑体积。可设置「千克」、「密度 kg/L」。Mass of water → US gallons. Settings: Kilograms, Density kg/L.
磅转杯（烹饪）Pound to Cup (Cooking)
按食材密度把磅换成美制杯。可设置「磅」、「食材」、「自定义 g/杯」。Pounds → US cups by ingredient density. Settings: Pounds, Ingredient, Custom g per cup.
流明转瓦特Lumens to Watts Converter
按光源光效把流明估算为电功率（W ≈ lm ÷ lm/W）。可设置「流明」、「光源」、「自定义 lm/W」。Estimate watts from lumens using luminous efficacy (W ≈ lm ÷ lm/W). Settings: Lumens, Source, Custom lm/W.
加仑转克（水）Gal to g (Water)
美制加仑水的质量（克）。可设置「加仑 (US)」、「密度 kg/L」。Mass in grams of US gallons of water. Settings: Gallons (US), Density kg/L.
加仑转盎司（液）Gal to Oz (Liquid)
美制加仑 ↔ 液盎司（1 gal = 128 fl oz）。可设置「加仑 (US)」。US gallons ↔ fluid ounces (1 gal = 128 fl oz). Settings: Gallons (US).
升转磅（水）Liter to lb (Water)
升水的磅数。可设置「升」、「密度 kg/L」。Pounds of litres of water. Settings: Litres, Density kg/L.
升转液盎司Liter to Oz
升 ↔ 美制液盎司（1 L ≈ 33.814 fl oz）。可设置「升」。Litres ↔ US fluid ounces (1 L ≈ 33.814 fl oz). Settings: Litres.
毫升转克（水）ml to g (Water)
毫升水的克数（ρ 可调）。可设置「毫升」、「密度 g/ml」。Grams of millilitres of water (adjustable ρ). Settings: Millilitres, Density g/ml.
毫升转磅（水）ml to lb (Water)
毫升水的磅数。可设置「毫升」、「密度 g/ml」。Pounds of millilitres of water. Settings: Millilitres, Density g/ml.
茶匙转克（烹饪）Tsp to g (Cooking)
按食材密度把美制茶匙换成克（1 tsp ≈ 4.9289 ml）。可设置「茶匙」、「食材」、「自定义 g/tsp（可选）」。US teaspoons → grams by density (1 tsp ≈ 4.9289 ml). Settings: Teaspoons, Ingredient, Custom g per tsp (optional).
克转升（按密度）Gram to Liter (by Density)
质量 ÷ 密度 → 体积（默认水 1000 g/L）。可设置「克」、「密度 g/L」。Mass ÷ density → volume (default water 1000 g/L). Settings: Grams, Density g/L.
克转毫升（按密度）Gram to Milliliter (by Density)
质量 ÷ 密度 → 毫升（默认水 1 g/ml）。可设置「克」、「密度 g/ml」。Mass ÷ density → ml (default water 1 g/ml). Settings: Grams, Density g/ml.
千克转升（按密度）Kg to Liter (by Density)
质量 ÷ 密度 → 升（默认水 1 kg/L）。可设置「千克」、「密度 kg/L」。Mass ÷ density → litres (default water 1 kg/L). Settings: Kilograms, Density kg/L.
磅转加仑（水）Lb to Gal (Water)
水的磅数 → 美制加仑。可设置「磅」、「密度 kg/L」。Pounds of water → US gallons. Settings: Pounds, Density kg/L.
克转茶匙（烹饪）Grams to Teaspoons (Cooking)
按密度把克换成美制茶匙。可设置「克」、「食材」、「自定义 g/tsp（可选）」。Grams → US teaspoons by density. Settings: Grams, Ingredient, Custom g per tsp (optional).
植物间距计算器Plant Spacing Calculator
按苗床长宽、株距和行距算出能种多少棵：方形网格（逐行对齐）给出实际可放下的株数，三角形（交错）排列给出按面积估算的株数（约多 15%）。Work out how many plants fit in a bed from its length, width, plant spacing and row spacing: the exact count for a square grid, and an area-based estimate for a triangular (staggered) layout, which fits about 15% more.
草籽用量计算器Grass Seed Calculator
按草坪面积、草种和播种方式（新建草坪或补播）计算需要多少草籽，以及按包装规格需要几袋；内置常见草种的示例播种量，也可填写种子袋上的推荐用量。Work out how much grass seed you need from the lawn area, grass type and whether you are seeding a new lawn or overseeding, and how many bags to buy — with example rates for common grasses, or the rate printed on your seed bag.
铺路砖用量计算器Paver Calculator
按铺装面积、砖块尺寸、缝宽和损耗率计算需要多少块铺路砖，以及碎石垫层和找平砂的体积（立方码 / 立方米）。Work out how many pavers you need from the patio area, paver size, joint width and waste allowance, plus the volume of gravel base and bedding sand (cubic yards / cubic meters).
甲板地板用量计算器Decking Calculator
按甲板长宽、板宽、板缝和板长计算需要多少块面板、龙骨数量和螺钉数，含损耗；面板沿长度方向铺设，龙骨垂直于面板按间距排布。Work out deck boards, joists and screws from the deck size, board width, gap and board length, with waste: boards run along the length and joists run across them at the chosen spacing.
挡土墙砌块计算器Retaining Wall Calculator
按挡土墙长度、高度和砌块尺寸计算砌块和压顶块数量，可加一层埋入地下的底层，并估算基础碎石和墙后排水碎石的体积。Count retaining wall blocks and cap blocks from the wall length, height and block size, with an optional buried first course, plus the gravel for the base trench and the drainage zone behind the wall.
窗帘尺寸计算器Curtain Size Calculator
按窗户宽高、窗帘杆超出窗框的长度、褶皱倍数和下摆位置，算出窗帘总宽度、每片宽度和长度，并给出最接近的常见成品长度。Work out curtain width per panel and length from the window size, how far the rod extends past the frame, the fullness and where the hem should fall — with the nearest common ready-made length.
土地面积（英亩）计算器Acreage Calculator
计算地块面积并换算成英亩、公顷、平方英尺和平方米：支持矩形、三角形、梯形、圆形，或按依次输入的边界坐标（鞋带公式）计算任意多边形。Find a plot's area in acres, hectares, square feet and square meters: rectangle, triangle, trapezoid, circle, or any polygon from its corner coordinates in order (shoelace formula).
斜接角度计算器Miter Angle Calculator
木工斜接：输入正多边形边数（如相框 4 边、六角形 6 边）或两块板相交的夹角，算出斜切锯的角度设置和每块板的切角。For woodworking miters: enter the number of sides of a regular shape (4 for a picture frame, 6 for a hexagon) or the angle at which two boards meet, and get the miter saw setting and the cut angle on each board.
塔可自助吧食材计算器Taco Bar Calculator
按成人和儿童人数、食量估算塔可派对需要多少饼皮、肉、米饭、豆子、奶酪、生菜、番茄、莎莎酱和酸奶油；按每人示例用量计算，可调整。Estimate taco bar food for a party from the number of adults and children and how hungry they are: shells or tortillas, meat, rice, beans, cheese, lettuce, tomatoes, salsa and sour cream, using example per-person amounts.
比例尺换算计算器Scale Conversion Calculator
按比例尺（如 1:24、1:100、1:50,000）在实物尺寸和模型或图纸尺寸之间换算，也能由一组实物和模型尺寸求出比例；支持不同的长度单位。Convert between real size and model or drawing size at a scale such as 1:24, 1:100 or 1:50,000, or find the scale from a real and a model size, with different length units on each side.
ACT 综合分计算器（新版 / 旧版算法）ACT Score Calculator (Composite & STEM)
按 ACT 官方规则计算综合分（Composite）：新版 ACT（2025 年 9 月起所有考试）取英语、数学、阅读三科平均，科学不计入；旧版取四科平均，0.5 及以上进位。同时给出 STEM 分，以及离下一个综合分还差几分。Work out your ACT Composite by ACT's official rule: on the enhanced ACT (all tests from September 2025) it is the average of English, Math and Reading, with Science left out; on the legacy ACT it is the average of all four, with halves rounded up. You also get the STEM score and how many more points reach the next Composite.
PERT 三点估算计算器（工期与完工概率）PERT Calculator (Three-Point Estimate)
按 PERT 三点估算公式 E = (O + 4M + P) / 6、σ = (P − O) / 6，逐项计算任务的期望工期和标准差，汇总关键路径总工期，并估算在截止日期前完成的概率和 80%/90%/95% 把握的工期。Apply the PERT three-point formulas E = (O + 4M + P) / 6 and σ = (P − O) / 6 to each task, total the critical path, and estimate the chance of finishing by a deadline along with the 80%, 90% and 95% confidence durations.
连衣裙尺码计算器Dress Size Calculator
输入胸围、腰围、臀围，按 Marks & Spencer 女装标准尺码表算出建议的连衣裙尺码，并换算成英国、美国、德国、法国、意大利、俄罗斯等地区尺码和字母码；可选填身高，得到中国服装号型（如 165/84A）。支持厘米和英寸。Enter your bust, waist and hips to get a suggested dress size from the Marks & Spencer standard womenswear chart, converted to UK, US, German, French, Italian and Russian sizes plus a letter size. Add your height (optional) for the Chinese GB/T 1335.2 size code, such as 165/84A. Works in centimetres or inches.
草皮用量计算器Sod Calculator
输入草坪长宽（或直接输入面积）和损耗比例，计算需要多少平方英尺 / 平方米草皮、多少卷和多少托盘，并可按单价估算费用。Enter your lawn's length and width (or its area) and a waste allowance to find how much sod you need in square feet or square metres, how many rolls and pallets, and an optional cost estimate.
外墙挂板用量计算器Siding Calculator
按房屋周长 × 墙高加山墙三角形面积，减去门窗面积并加损耗，计算外墙挂板需要多少平方英尺 / 平方米和多少「方」（square，100 平方英尺），并可估算费用。Work out how much siding you need: perimeter × wall height plus the gable triangles, minus doors and windows, plus waste — in square feet or square metres and in squares (100 sq ft), with an optional cost.
保温层厚度与用量计算器Insulation Calculator
按目标 R 值、现有 R 值和保温材料的每英寸 R 值，计算还需要多厚的保温层、总体积，以及按包装覆盖面积需要几包；材料 R 值取自美国能源部和 PNNL 资料，也可自定义。Work out how thick your insulation needs to be from a target R-value, any existing R-value and the material's R-value per inch, with the total volume and the number of bags or packs from the coverage on the label. Material R-values come from US DOE and PNNL references, or enter your own.
泳池容积计算器Pool Volume Calculator
按矩形、圆形、椭圆形或肾形泳池的尺寸和浅端、深端水深，计算水量（立方英尺 / 立方米、美制加仑、升），并可按水泵流量估算注水时间。Find how much water your pool holds — rectangular, round, oval or kidney-shaped — from its size and shallow and deep-end depths, in cubic feet or metres, US gallons and litres, with an optional fill time from your pump or hose flow rate.
鱼缸容积计算器Aquarium Volume Calculator
计算长方体、圆柱、弧面（弓形前脸）、六角形和转角扇形鱼缸的水量（升、美制加仑、英制加仑）和水重，可扣除玻璃厚度和水面到缸口的距离。Work out how much water an aquarium holds — rectangular, cylindrical, bow-front, hexagonal or corner (quarter-circle) — in litres, US and UK gallons, with the weight of the water, optionally allowing for glass thickness and the gap below the rim.
蛋糕模具换算器Cake Pan Converter
把配方从一种蛋糕模具换到另一种：按圆形、方形或长方形模具的底面积（可多个模具）算出放大或缩小的倍数，并可直接把配料表按倍数换算。Convert a recipe from one cake pan to another: compare the base areas of round, square or rectangular pans (one or several) to get the scaling factor, and scale your ingredient list by it.
轮毂 ET 偏距计算器Wheel Offset Calculator
比较新旧两款轮毂的宽度和 ET 偏距，计算后距（backspacing）、前距，以及换装后轮胎内侧离悬挂更近或更远多少、外侧向外凸出或缩进多少毫米。Compare two wheels by width and offset (ET) to get each one's backspacing and front spacing, and how much closer the inside moves to the suspension and how far the outside pokes out or tucks in after the swap, in millimetres.
保龄球平均分计算器Bowling Average Calculator
根据总瓶数和局数计算保龄球平均分：平均分 = 总瓶数 ÷ 局数。给出精确平均分和联赛取整（向下取整）平均分，并可按“基准分 × 百分比”计算让分（handicap）。Work out a bowling average from total pinfall and games: average = total pinfall ÷ games. Shows the exact average and the league (rounded-down) average, and can compute a handicap from a basis score and percentage.
胶合板/板材用量计算器Plywood Sheet Calculator
根据要覆盖的面积和单张板材尺寸，计算需要多少张胶合板（或 OSB、石膏板等板材）：含损耗余量，向上取整为整张。支持英制（ft）和公制（m），并给出总面积和总价。Work out how many sheets of plywood (or OSB, drywall and similar) you need to cover an area — including a waste allowance and rounded up to whole sheets. Works in feet or metres and gives the total area and cost.
百分制转 GPA 计算器Percentage to GPA Converter
把百分制成绩按常见的美国 4.0 分制换算为 GPA 绩点和字母等级（A+/A/A−…F）。另提供简单线性估算 GPA ≈ (百分数 − 60) ÷ 10（不超过 4.0）。各校标准不同，结果仅供参考。Convert a percentage grade to a GPA and letter grade on the common US 4.0 scale (A+/A/A−…F). Also offers a simple linear estimate GPA ≈ (percentage − 60) ÷ 10 (capped at 4.0). Scales vary by school, so treat the result as a guide.
土壤/花园用土量计算器Soil Calculator
计算花坛、菜畦或容器需要多少土壤/堆肥：按长 × 宽 × 深求体积，给出立方英尺、立方码、升和立方米，并按袋装容量换算所需袋数。支持英制（ft/in）和公制（m/cm）。Work out how much soil or compost a garden bed, raised bed or container needs: length × width × depth gives the volume in cubic feet, cubic yards, litres and cubic metres, plus the number of bags for a given bag size. Works in feet/inches or metres/centimetres.
施肥量计算器Fertilizer Calculator
按目标氮肥施用率和肥料养分含量，计算草坪或菜地需要多少肥料；也可反过来，由已知肥料用量算出实际施入的氮量。支持每 1000 平方英尺（lb）或每 100 平方米（kg）两种常用施用率。Work out how much fertiliser a lawn or bed needs from a target nitrogen rate and the product's nutrient content — or, the other way round, the actual nitrogen delivered by a known amount of fertiliser. Supports the two common rates: pounds per 1,000 sq ft and kilograms per 100 m².
经纬度坐标系转换（WGS84/GCJ-02/BD-09）Coordinate Converter (WGS84 / GCJ-02 / BD-09)
在 GPS 使用的 WGS84、高德/腾讯/谷歌中国使用的 GCJ-02（火星坐标）和百度地图使用的 BD-09 之间批量转换经纬度，解决坐标放到地图上偏移几百米的问题。Batch-convert latitude/longitude between WGS84 (GPS), GCJ-02 (used by Amap, Tencent and Google Maps in China) and BD-09 (Baidu Maps), fixing the few-hundred-metre offset when plotting points on Chinese maps.
经纬度度分秒转换Degrees Minutes Seconds Converter
经纬度在十进制度（39.9087°）和度分秒（39°54′31.3″N）、度+十进制分之间互相转换，支持批量和各种写法，自动识别南纬、西经。Convert latitude/longitude between decimal degrees (39.9087°), degrees-minutes-seconds (39°54′31.3″N) and degrees + decimal minutes, in batches and with almost any notation, including S/W hemispheres.
硬盘整数分区计算器Disk Partition Size Calculator
计算 Windows 下分出「整数 GB」分区需要填写的 MB 数（如 100 GB 填 102796 MB），并把硬盘标称容量换算成系统里显示的实际容量，规划分区后还剩多少空间一目了然。Work out the MB value to enter so a Windows partition shows as a whole number of GB (e.g.